Blog on Bald Engineer

Replacing Electrolytic Capacitors | VCF Midwest 2025 Talk

Sun, 14 Sep 2025 02:17:41 +0000

Slides PDF: Electrolytics are Ticking Time Bombs Bit Preserve: GitHub Repo with Vintage Computer Schematics in KiCad Bald Engineer’s Capacitor Video Playlist TRS 80 Model 100 Cap Replacement Spreadsheet (add a pitch column!) Talk for Vintage Computer Festival Midwest #20 (2025).

Can Polymer Capacitors Replace MLCCs?

Wed, 16 Apr 2025 16:45:32 +0000

Multi-layer ceramic capacitors (MLCCs) are so ubiquitous that you see them on almost every printed circuit board. Engineers and supply chain managers often ask whether polymer electrolytic capacitors can replace MLCCs. The replacement could be because of availability, or an application cannot tolerate the extreme capacitance loss with MLCC’s DC Bias Effect. This video demonstrates what happens when you replace MLCCs with Polymer Tantalum (KO-CAP) capacitors.

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Exploring DIY PCB Assembly versus Turnkey Services with MacroFab and Bald SENSE

Tue, 27 Aug 2024 14:56:59 +0000

Experience comparing DIY and Turnkey PCB assembly with the Bald SENSE project. This journey started almost four years ago. Thanks to a collaboration with MacroFab, I am finally collecting valuable environmental data with my custom Feather Wing. A big thank you to MacroFab for manufacturing the boards and sponsoring the video. I also want to thank Unexpected Maker for their noteworthy contribution to the FeatherS3 microcontroller boards, which played an essential role in the video.

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STOP! Using the Wrong Capacitors | Teardown 2024

Thu, 20 Jun 2024 02:04:11 +0000

Learn more about Teardown 2024 Google Slides Download Slides (PDF) Links Circuit Break Podcast #434: The Other VCC Circuit Break Podcast #141: It Depends MLCCs with James Lewis YouTube: Bald Engineer’s Capacitor Videos Hioki USA: Unlocking the Secrets of Capacitor Impedance Plots Murata: SimSurfing Yageo Group / KEMET: K-SIM

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B&K Precision DAS60 Hands-On

Wed, 05 Jun 2024 16:42:26 +0000

The B&K Precision DAS60 is a data recorder. It features 6 wide-range voltage inputs, 16 digital channels, and RTD thermal sensor inputs and comes in a small compact form factor. In this video, I show what it can do. The DAS60 is designed for lab and fieldwork. Its built-in battery means you can deploy it in a facility and let it log data. It has built-in ethernet and support for generic Wi-Fi dongles. The computer runs Windows CE and has RealVNC pre-installed. This combination lets you connect remotely to configure the instrument, check its status, or review recorded data.

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Retro Repairs RoundUp Appearance

Mon, 03 Jun 2024 23:35:11 +0000

The Retro Repairs RoundUp crew invited me to be a guest on episode 56 of their livestream. As their name implies, they discuss retro computers and, in many streams, how to repair them. We mostly discussed the Mega IIe project. Sean was another guest who talked about KansasFest 2024. KansasFest is an Apple II conference. This year, it moved its venue to Springfield, Illinois. The name and the location might seem confusing; however, it was long held in Missouri. So, it is a case of the name sticking for historical reasons.

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Mega IIe Supercon 2023 Talk is now Live!

Wed, 15 May 2024 13:06:13 +0000

I must extend a big “Thank You!” to Lewin Day at Hackaday for this excellent Mega IIe write-up. Accompanying the post is an archived recording of my Supercon 2023 talk. That talk is where I gave a complete overview of the Mega IIe project and showed off the final case design for the first time! This project is where I took the Mega-II chip out of an Apple IIGS and built a fully compatible Apple IIe around it—something that not even Apple ever did!

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NXP's MCX FRDM Board Hands-On

Wed, 01 May 2024 16:59:43 +0000

Check out NXP’s latest microcontroller boards. These boards of their new MCX-A and MCX-N microcontrollers. The form factor is what NXP calls Freedom (FRDM.) The MCX line of microcontrollers, each with its unique set of features, caters to a wide range of projects. The MCX-A, a general-purpose microcontroller, is ideal for entry-level projects, while the high-performance MCX-N is designed for advanced AI/machine learning tasks. NXP recently started shipping the MCX-N, adding to its versatility and appeal.

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WiFi-Enabled LED detector tells me when my Dehumidifier is Full!

Fri, 12 Apr 2024 23:40:13 +0000

I created a Wi-Fi-enabled LED Detector using Nordic’s nRF7002 Design Kit (DK). Using this box, I can detect when LEDs on appliances, like my lab’s dehumidifier, are on. In other words, my non-IoT tool can send me messages over the Internet now! And, because the nRF7002 has a dual-band Wi-Fi antenna, it does so on my 5 GHz network. I ran into a number of issues with this project, and I expected that. Except for the RF part of the design, which works fine! Links to the design files are available on the post on the element14 Community.

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From MLCC to Polymer: Unlocking Capacitor Impedance Plot Secrets

Tue, 02 Apr 2024 16:41:10 +0000

April 17, 2024, at 1:00 pm CDT Register Now Capacitors are deceptively complex devices. It is why I love talking about them so much! Hioki USA loaned me an LCR Meter that works as an Impedance Analyzer to try out some measurements. As a result, I noted a few things that might catch someone off guard if they have never attempted to characterize capacitors. For example, many of us know about the MLCC DC Voltage Coefficient. However, do you know how to evaluate whether your parts lose 20 or 80% of their capacitance? Or, what considerations do you need to make when measuring a polymer electrolytic versus a film capacitor?

Measuring Apple II CPU's Glitchy Clock

Wed, 20 Mar 2024 17:58:51 +0000

The Apple II’s CPU clock has jitter or a glitch. This issue is not new—it has been present since its original design in 1977! Bald Engineer uses an oscilloscope to show how often the glitch occurs and how to correlate that jitter to its source—which is useful when you are not testing 40-year-old devices. The device under test (DUT) in this video is the Mega IIe project. It’s a fully compatible Apple IIe built around the Mega II chip.

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Picking I2C Pull-Up Resistors (Correctly)

Thu, 07 Mar 2024 13:22:00 +0000

A long time ago, I made a video suggesting math was unnecessary to determine proper pull-up resistor values. Like most generalized statements, that suggestion is not always true. For example, in data buses like I2C, speeds like 400 kHz and 1 MHz are common. At those speeds, the pull-up resistor and the bus capacitance form an RC filter that fundamentally limits the data transmission speed. Or. It limits the range of pull-up resistor values. In this Workbench Wednesdays video, I show how to estimate I2C bus capacitance, measure that capacitance, and pick pull-up resistor values.

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A Vintage Computing Adventure (Mega IIe)

Wed, 06 Mar 2024 04:35:16 +0000

Your browser does not support the video element. Parker and Stephen invited me back to discuss the Mega IIe project on the MacroFab Circuit Break podcast. This discussion was far more casual than my past appearances. It was the first time I didn’t feel the need to do any prep work for their excellent questions! We talked through the overall experience of rev 1, rev 2, and rev 3. I appreciated the chance to talk about my motivations behind the Mega IIe project, why I like the Apple II platform so much, and getting to nerd out with Parker on analog video signal concepts.

Eight KiCad 8 features I like

Mon, 26 Feb 2024 16:23:38 +0000

KiCad 8 just dropped. Here’s an AddOhms video covering eight must-try features! The February 2024 release brings a whole host of new stuff to the Schematic editor. However, the PCB editor, CLI, and Simulation tools also received attention. (There are something like 900 closed issues for the 8.0.0 Milestone!) Which of these is your favorite? In the video, I cover: Property Manager Panel (is now everywhere) A fix for Symbol pin or wire end off connection grid! Easily access alternate pin functions (on symbols with them) Pin Helpers save time Edit Power Symbols (instead of creating new library parts) Net Navigator and Search panels help with large schematics Improved custom polygon tools in PCB (Combined) Teardrop support and Length-Tuning improvements This AddOhms post covers my top 8 in more detail. Or, you could just watch the video!

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Accessing USB instruments with pyvisa on Linux

Tue, 13 Feb 2024 21:27:23 +0000

USB-Based instruments that do not appear to the host as a virtual com port (VCP) usually use libusb for communication. The pyvisa-py driver for pyvisa can communicate with these instruments. However, you must first create a udev rule (and possibly a user group.) If you see the device in lsusb, but not the pyvisa ResourceManager, you need to add (or modify a udev rule): # backup 99-com.rules (if it exists) cp /etc/udev/rules.d/99-com.rules /etc/udev/rules.d/99-com.rules.BAK # (create and) edit the file nano /etc/udev/rules.d/99-com.rules # Add the following line SUBSYSTEM=="usb", MODE="0666", GROUP="usbusers" # create a usbusers group sudo groupadd usbusers # add your account to the new group sudo usermod -a -G usbusers USERNAME # restart udev /etc/init.d/udev restart (Although, you are probably better off rebooting.)

nRF7002 DK vs EK vs EB Hands-On

Thu, 01 Feb 2024 13:53:00 +0000

In August 2022, Nordic Semiconductor announced its first Wi-Fi product. The nRF7002 is a dual-band (2.4 and 5 GHz) Wi-Fi 6 compatible companion IC. It does not have a general-purpose microcontroller built-in. Instead, Nordic intends for you to combine it with another microcontroller, like one of their nRF52 or nRF53-series system on chip (SoC). Nordic and the element14 Community sent me an nRF7002 Development Kit (DK), Evaluation Kit (EK), and some nRF7002 QFNs. I reviewed the nRF70 variants in this video and looked at the various boards. As the thumbnail suggests, I connected the Wi-FI transceiver to a FPC1500 spectrum analyzer.

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RP2040 Debug and Turn-On Tips

Wed, 31 Jan 2024 17:35:18 +0000

During the component shortage, I got to know Raspberry Pi’s RP2040 microcontroller. It is a dual-core Arm Cortex-M0+ with about 262 kilobytes of RAM. The feature I like most is the programmable IO pins. These are small state machines that run independently of the Arm cores. They allow for some clever tricks. For example, I used them extensively on the Mega IIe project. This video was supposed to be a project I thought of during the Mega IIe. I call it a state-mode logic analyzer. However, it took me several days to turn on and debug four boards. Time ran out, so I focused the video on debugging custom RP2040-based boards. These are all lessons I have learned from this project, plus about another dozen RP2040 boards I have built over the past couple of years.

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Mega IIe Picture Album

Wed, 20 Dec 2023 13:36:00 +0000

Most of these pictures from the Mega IIe project did not make it into a video or talk. There were many “behind the scenes” style shots. Some of the pictures have titles and descriptions. I work on them when I have free time. Let me know your favorite! https://www.flickr.com/photos/cmiyc/albums/72177720312911955/ Mega IIe Album on Flickr Navigate one picture at a time with the left/right arrows, or follow the link below to see the full album.

Mega IIe Supercon Links

Sat, 04 Nov 2023 20:56:28 +0000

These links accompany the Mega IIe presentation at Supercon 2023. Mega IIe Github Repo World’s first single-chip Apple II boots Twitch Mega IIe Livestream Archive Bit Preserve Project David Schmidt’s Tiger Learning Computer Project Pico VGA Library Social Media Links Mastodon YouTube (https://x.com/baldengineer) Facebook Bluesky Workbench Wednesdays HacksterIO Articles Live Streaming Slides PDF of the Slides (23mb) Thank You

Hamvention 2023 Pick Ups

Fri, 26 May 2023 18:49:52 +0000

The Dayton Amateur Radio Association (DARA) hosted Hamvention 2023 in Xenia, Ohio, on the weekend of May 19th. This annual event is the largest gathering of amateur radio operators. Sprawled across the Greene County Fairgrounds and Expo Center are commercial vendors selling gear or services, educational talks, license exams, and a massive flea market. Of the various activities, my favorite is to wander around the dozens of rows of people selling items in the flea market. For some people, this is the only reason even to attend! Here are a few of the things I picked up and plan to do some work on.

Difference between flux (for soldering)

Wed, 17 Aug 2022 13:17:00 +0000

Often I hear this question: “how can I get better solder joints?” Without looking at anything they are doing, I already know that they could be using more flux. Or, as I point out in this video, perhaps the correct type of flux! Flux removes oxide layers, gets contaminants out of the way, and makes for better solder joints. But there are so many different types of flux and even more ways to apply it.

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Oscilloscope Trigger Primer

Thu, 04 Aug 2022 17:54:34 +0000

A powerful, but an underused feature of digital oscilloscopes is the trigger circuit. Learn from James how to use an oscilloscope’s trigger to find glitches, measure pulse widths, see transients, and stabilize a scope’s screen. This video explains the difference between Auto and Normal sweep modes, shows how to use a Pulse Width trigger, and explains how to use Hold-Off.

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How to Profile Battery Usage for IoT Devices

Sat, 25 Jun 2022 13:08:00 +0000

When running on a battery, it is important to know what parts of your circuit draw the most current. Profiling is a process where you look at sections of code or interactions with hardware to see how much power each requires. In this video, James shows four tools (and their tradeoffs) when profiling IoT or Edge Machine Learning devices. See if it makes more sense for you to use a Digital Multimeter (DMM), Power Supply with history graphs, an oscilloscope

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Do ALL Scope Probes Need Ground?

Fri, 24 Jun 2022 13:05:00 +0000

When connecting multiple oscilloscope probes to a circuit, does each probe need to connect to ground? The short answer is yes! Why? The long answer is kind because of the ground loop. Remember, a circuit needs a closed path. And while on DC circuits we may rarely think about the distance of that path, it absolutely matters when there is an AC or frequency component. When you do not connect each probe’s ground, the signal path because enormous since it must connect to the circuit’s ground through another probe. (See the animation in the video above.)

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How Oscilloscope Acquisition Modes Work

Thu, 23 Jun 2022 13:38:00 +0000

Every digital oscilloscope I have ever used has a menu or dialog for “acquisition modes.” And depending on the current settings, changing that acquisition mode does not seem to have an effect on the signal. Or sometimes, changing to something like Average mode can completely destroy your measurements. It turns out, that the analog-to-digital converters in digital oscilloscopes can do more than just “sample” the data. Well, the ADCs just samples. The controller behind the ADC offers modes like Peak Detect and Average and High-Resolution.

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Hands-On with B&K Precision 9140 Power Supply | Workbench Wednesdays #53

Wed, 22 Jun 2022 15:36:22 +0000

Bench power supplies are an essential piece of test equipment gear. And like most test gear, they have a wide range of capabilities. For example, the B&K Precision 9140 is a triple output supply that can output up to 300 watts. But, the basic capability isn’t what interested me about the supply. Instead, it was advanced features like rear panel triggers, adjustable slew rate, and built-in sequencing. The element14 Community arranged for a B&K Precision 9140 power supply to be sent to me for a hands-on overview of those features.

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KiCad: Connect Polygon Lines

Thu, 09 Jun 2022 16:55:58 +0000

fix broken polygons in kicad In KiCad 6, using the Polygon tool makes square boards easy. Just select the Edge.Cuts layer, then the polygon tool, and draw a square. However, if you want custom shapes, then you need to connect multiple line segments together. If you are not careful, the segments will not connect and you might get one of two errors. The first comes when you run DRC.

Three Tips to Improve Your Soldering | Workbench Wednesdays #52

Fri, 11 Mar 2022 00:25:00 +0000

Using a Metcal GT120, we look at three ways to improve your soldering skills. Using flux, setting a correct temperature, and selecting the proper tip all result in better solder joints. See how well the GT120 works while learning (or reviewing) some basics to improve your soldering skills. This episode was sponsored by Metcal.

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How to Measure Ripple Voltage on a Switch-Mode Power Supply | Workbench Wednesdays #51

Tue, 01 Mar 2022 00:23:00 +0000

Measuring a switch-mode power supply (SMPS) with a DMM might show a stable voltage. But the same DC rail on an oscilloscope can show a completely different story! In this video, learn how to correctly set up an oscilloscope to characterize the noise an SMPS creates in a circuit.

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DIY Solder-In Oscilloscope Probes | Workbench Wednesdays #50

Thu, 03 Feb 2022 00:19:00 +0000

When you cannot get an oscilloscope probe into a tight spot, can you just use a piece of wire? Sometimes. When signal integrity matters, you CAN use a low-cost DIY solder-in probe. These probes attenuate the signal and use an oscilloscope’s high-bandwidth 50-ohm input. James shows how to build some solder-in probes when they work and when they do not work in this video. Special thanks to Shabaz on the element14 community for the guide used here.

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Instrument Basics: Vector Network Analyzer (VNA) with PicoVNA | Workbench Wednesdays #49

Wed, 19 Jan 2022 00:15:00 +0000

Vector network analyzers (VNAs) measure how a “network” of components changes the amplitude and phase of signals. By measuring across a wide frequency range, VNAs can create S-Parameters that fully describe the behavior of a circuit. This video uses a PicoVNA 106 to show the basics of what a VNA measures, how they work, and a brief overview of how to use one. I made a mistake on the explainer graphic for S-parameters. The annoying thing is that I think it was a really good explanation!

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Exploring the Digilent Analog Discovery 3000 Pro Series | Workbench Wednesdays #48

Wed, 15 Dec 2021 00:11:00 +0000

Analog Discovery Pro from Digilent comes in a 2-channel (ADP3250) or 4-channel (ADP3450) version. These all-in-one instruments work with a PC over USB or can run entirely standalone. On the PC the excellent Waveforms software provides virtual instruments like an Oscilloscope, Logic Analyzer, Power Supply, Spectrum Analyzer, Curve Tracer, Network Analyzer, and Impedance Analyzer. Just to name a few. See what this new instrument offers in this hands-on review. This episode was sponsored by Digilent.

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What does Bandwidth mean for Oscilloscopes? | Workbench Wednesdays #47:

Fri, 12 Nov 2021 00:08:00 +0000

Using the Rohde and Schwarz RTH1004 ScopeRider, James talks about oscilloscope bandwidth. In this video, learn what oscilloscope bandwidth is, and what it is not, and see two measurements that help you tell if you are being band-limited by an oscilloscope. The episode was sponsored by Rohde & Schwarz.

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Pros and Cons of Low-Temp Solder Paste | Workbench Wednesdays #46

Mon, 25 Oct 2021 23:03:00 +0000

Low-temperature solder paste makes it easier to reflow-solder and re-work surface mount circuit boards. MG Chemicals offers a Bismuth-based paste that works great from larger passive components to fine pitched packages, like QFN. In this video, learn what solder paste is, what it means for a paste to be “low temperature,” and some things to watch out for when using it. This episode was sponsored by MG Chemicals.

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160 MHz Arbitrary Waveform Generator Review | Workbench Wednesdays #44:

Mon, 20 Sep 2021 22:59:00 +0000

Arbitrary waveform generators can generate almost any waveshape. In this video, see how the MP750290 from Multicomp Pro performs. Its key specs are 160 MHz, 14-bit 1.25 Gigasample per second digital-to-analog converter, 1 million point memory, and over 150 built-in waveforms. The episode was Sponsored by Multicomp Pro.

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The Origins of Delayed Timings on Oscilloscopes | Workbench Wednesdays #43

Tue, 31 Aug 2021 22:57:00 +0000

Almost everyone uses a digital oscilloscope’s zoom features. However, did you know that 40-year-old analog oscilloscopes can do something similar? Delayed time bases on analog scopes sweep twice so that the user can see a slow and fast sweep. In this video, see where “zoom” came from and how engineers accomplished the same measurement back in the day.

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Compare Ideal vs. Real Filter with an LCR Meter | Workbench Wednesdays #42

Thu, 05 Aug 2021 22:51:00 +0000

Compare the ideal and measured cut-off frequency for a filter with a handheld LCR meter. Unlike a DMM, these meters apply an AC signal (from 100 Hz to 100 kHz) to determine the reactive component of an inductor, capacitor, or resistor. A simple example here is a low-pass filter. See how the ideal and measured cut-off frequency varies. And THEN, see how it compares between a PCB and a Breadboard.

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How Eaton's Power Defense Circuit Breakers Work | Workbench Wednesdays #41

Thu, 15 Jul 2021 22:45:00 +0000

Circuit breakers make electricity safe in everyday life. The miniature breakers found in your home are relatively simple devices. Commercial units like the Eaton Power Defense with PXR Trip units are found everywhere, even if we do not see them. Learn how a basic circuit breaker works and get some insight into these advanced electronic controlled Circuit Breakers. In this video, I got to interview Andy at Eaton. He was an interesting person and very knowledgeable about circuit breakers. I had no idea how much technology went into them.

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Measurements with an SMU | Workbench Wednesdays #40

Tue, 22 Jun 2021 22:43:00 +0000

Source Measurement Units, or SMUs, combine an accurate power supply, high-power electronic load, and precise digital voltmeter into a signal unit. They are a four-quadrant source. That means they can provide power to a circuit or consume it. With an SMU you can characterize semiconductor devices (like Diodes), monitor the power consumption of a circuit, or simulate a battery. In this video, see the difference between an SMU and a Power Supply.

Op Amps Without Op Amps | Workbench Wednesdays #39

Tue, 08 Jun 2021 22:35:00 +0000

Okay, technically, this circuit *does* use Op-Amps. However, the ones shown here are integrated into an ATmega128DB microcontroller from Microchip. The DIP package breaks out two operational amplifiers that are controllable entirely by software. Even better, you can program them like they are an Arduino!

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Which Oscilloscope Form Factor Is Best For Me? | Workbench Wednesdays #38

Fri, 21 May 2021 22:30:00 +0000

Oscilloscopes are available in many shapes and sizes. After figuring out how much bandwidth you need (or want), the next step is to choose the form factor. Do you go with the traditional bench style? When does it make sense to use a USB-based scope with your PC? And what about these newer tablets or battery-powered oscilloscopes? Learn the difference between them and see which one is best for you.

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Desoldering Wick Tips and Tricks with Superwick | Workbench Wednesdays #37

Mon, 12 Apr 2021 22:14:00 +0000

Desoldering braid removes surface solder from a circuit board. It makes reworking PCBs easy and quick. With a few tips and tricks, products like MG Chemical’s Superwick can work like magic. You can remove solder from surface mount parts, wick away excess solder blobs, and repair boards using it. In this video, James shares tips and tricks from the element14 community for using desoldering braid. (Please note: the makers of Superwick, MG Chemicals, sponsored this video)

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Essential Logic Families | Workbench Wednesdays #35

Tue, 02 Mar 2021 23:07:00 +0000

Did you know that TTL chips do not output 5 volts? 74LS, 74HC, and 74HCT all have different input and output thresholds. Switching between logic families can be difficult if you are not careful. In this video, learn how different 7400-series logic families compare with input threshold, output voltage, frequency, rise time, and propagation delay. Check out this TI Application Guide for a great resource on logic families.

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Triggering And Decoding Serial Protocols On An Oscilloscope | Workbench Wednesdays #34

Tue, 02 Feb 2021 23:03:00 +0000

Everything with a microcontroller has serial buses in it. Busses like UART, I2C, and SPI are very popular choices. When you have a problem with a sensor that uses one or the bus itself, you can use an oscilloscope or logic analyzer to “decode” the traffic. These decoders convert the 1s and 0s into readable HEX or ASCII characters. I am not sure how I thought of the “multiple” James idea for the thumbnail. The concept had something to do with “serial,” but I am not sure what.

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Measuring A 555 On An Oscilloscope | Workbench Wednesdays #33

Fri, 01 Jan 2021 23:00:00 +0000

The 555 is a very popular chip, and for good reason. It is such a versatile timer. Learn about 555 measurements like how to measure the voltage divider inside the chip and what is going on with the signals in an astable multivibrator (clock) circuit. The key to a 555 circuit is connecting the threshold and trigger pins together. But, until you see the schematic and waveforms it may not be obvious why.

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UPS ESR Battery Measurements | Workbench Wednesdays #32:

Tue, 15 Dec 2020 22:57:00 +0000

As batteries age, their ESR goes up. Eventually, they will no longer be serviceable. A battery measurement tool like the Hioki BT3554 lets field service technicians monitor the help of batteries over time. In this video, see how it can be used to measure a live UPS battery. This episode was sponsored by Hioki.

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Essential Consumables for Building Circuits | Workbench Wednesdays #31:

Wed, 18 Nov 2020 22:48:00 +0000

Obviously, you need solder to build most circuits. However, before and after soldering a circuit, there is a bunch of other stuff. In this Workbench Wednesdays episode, James looks at the solder, flux, wick, and cleaning supplies needed when working with electronics. Make sure your lab is stocked with these must-have consumables.

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Ceramic Capacitor Voltage Effect | Workbench Wednesdays #30

Wed, 28 Oct 2020 21:46:00 +0000

Ceramic capacitors change capacitance with applied voltage, temperature, and age. They are the most popular electronic component, yet many do not understand what causes this capacitance to change. In this video, James teams up with Murata to see what happens to a simple timer circuit when changing a capacitor from a 1206 case size to a much smaller 0201.

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What Active Components Do You Need? | Workbench Wednesday #29

Thu, 08 Oct 2020 21:43:00 +0000

Active components like transistors, BJTs, MOSFETs, and integrated circuits (ICs) make it possible to control circuits. This video explains the must-have NPN and PNP BJTs. For MOSFETs there are a couple of N-Channels and P-Channels to consider. Basic ICs include some digital logic stuff from the 7400-family as well as the venerable 555-timer to have on-hand. We did not forget Op-Amps either. Spoiler: We do not recommend the ua741!

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What Passive Components Do You Need? | Workbench Wednesdays #28

Wed, 09 Sep 2020 21:41:00 +0000

Whether you are just getting started in electronics or you have boxes of parts, it is good to know what are the most critical parts to have in your kit. James asked the element 14 community for what they considered to be essential passive components like resistors, capacitors, switches, wires, and even diodes. In this video, he consolidated their puts and explains what to think about when buying these parts for your kit.

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Instrument Basics: Logic Probe | Workbench Wednesdays #27

Thu, 13 Aug 2020 21:36:00 +0000

Logic probes are great for debugging 7400 series logic chips and digital circuits. In this video, James makes a counter circuit and debugs each stage as he builds, with a Logic Probe. If you are wondering, “do I need a logic probe” this video shows how one can be used and even answers when you should consider buying one.

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How to Measure Sound with a Handheld Meter | Workbench Wednesday #26

Tue, 07 Jul 2020 21:31:00 +0000

One of the loudest pieces of equipment on Bald Engineer’s electronics workbench is the Electronic DC Load. James has finally had it with its noise and decided to swap the fan out. To see (and not just hear) an improvement, he uses a Tenma 72-942 handheld sound meter to compare before and after. Full notes on element14 community

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Measuring a MOSFET's Miller Plateau | Workbench Wednesdays #25

Tue, 07 Jul 2020 21:28:00 +0000

Turning on a MOSFET takes more than knowing the threshold voltage. A special event occurs when a FET turns on, which is called the Miller Plateau. The gate voltage sticks to the threshold voltage while the drain opens up. In this video, James shows how to measure the Miller Capacitance, using an oscilloscope and custom MOSFET test board. This video came from some measurements I did on a live stream. I had intended to demonstrate something else, but the board I created was such a great demo board for the Miller Effect.

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No-Contact Current Measurements | Workbench Wednesday #24

Tue, 05 May 2020 21:25:00 +0000

One of the safest ways to measure current is with a clamp. Clamps do not require you to break the circuit and they safely measure wires with thousands of amps. In this video, we measure DC current in the lab, AC current of a reflow oven controller, and the DC current in a car using a Tenma 72-7226 True RMS Clamp Meter. This video was the last one I did before moving to a new house / lab.

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What that DMM Beep Means - A Continuity Mode Tutorial | Workbench Wednesdays #23

Tue, 28 Apr 2020 21:23:00 +0000

Chances are, you have used the continuity mode of your digital multimeter. But how much do you understand about how it works? In this video, we break down how the mode works, what the beep means, and show examples of how to use it (correctly.) It might seem silly to spend so much time on such a simple mode. However, I have run across a few posts on the Internet, including the element14 Community where people do not understand continuity mode. Sometimes it is just a lack of experience and sometimes it is a total lack of understanding of what is happening. The biggest mistake, of course, is trying to measure continuity on a powered circuit. That is just a no-go. So in this video, I wanted to show what the meter is actually doing, how it sees different components, and give a couple of real-life examples of how to use it.

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Instrument Basics: LCR Meter | Workbench Wednesdays #22

Wed, 01 Apr 2020 23:31:00 +0000

Learn how to use an LCR meter, such as the Tenma 72-10465, to measure reactive components. An LCR meter uses an AC signal at different frequencies to characterize capacitors, inductors, and even resistors. They can also provide impedance measurements. These include phase angle, ESR, quality factor, and dissipation factor. You can even use the 72-10465 to sort components by their tolerance range.

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DMM Half-Digits Explained | Workbench Wednesdays #21

Thu, 05 Mar 2020 22:20:00 +0000

What does it mean for a DMM to have 3.5 digits? How much more accurate is a 5.5 digit multimeter versus a 4.75 digit meter? Many people assume that more digits mean more accuracy. However, these numbers express the precision of the meter, not its accuracy! In this video, learn about a DMM’s accuracy, and what does “half a digit” mean. As I often do, I messed up the decimals in this one.

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Thermal Tools for Circuit Measurements | Workbench Wednesdays

Sun, 23 Feb 2020 17:48:14 +0000

Measuring the effectiveness of a heatsink or the thermal load of a CPU requires thermal test tools. In this episode, learn how an IR Thermometer and a Thermocouple could be used on an electronics workbench. Many multimeters (DMMs) include the ability to measure temperature with a K-type thermocouple. See examples of when each measurement could be used. Behind the scenes of Thermal Tools Tutorial Originally intended to use the episode to show how hot the Pi 4 would get. However, by the time I got around to producing it, a new version of Raspbian came out, resolving the temperature issues. To heat up the Pi, I used this toolset from GitHub: XXXXX.

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DMM Basics Video Tutorial | Workbench Wednesdays

Sun, 23 Feb 2020 16:47:49 +0000

A multimeter is the go-to-tool for electronics measurements. Knowing how to use it to measure voltage, current, diodes, and transistors can save time (and frustration) while troubleshooting. In this video, James explains how the multimeter works, so that you can understand them better. After watching, you will gain a solid DMM basics understanding. Behind the scenes of wbw’s DMM Basics The first Workbench Wednesdays episode covered a pen-style DMM. Back when we were first developing the show, the intent was to be more of a review show and less of a tutorial show. That episode became a mix of both. So we decided to do a straight-up tutorial on DMM basics. Measuring voltage usually has not tripped up too many people, especially on an auto-ranging meter. The main thing to remember with current is to move the red lead back to the voltage input immediately after making a measurement. I touched on continuity briefly but hope to come back and cover that more in the future.

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4-Wire Resistance Tutorial | Workbench Wednesdays

Sun, 23 Feb 2020 16:31:31 +0000

Bench DMMs have an extra set of banana jacks called “sense.” Known as a Kelvin or 4-wire resistance measurements, these inputs accurately measure small resistors. Like, milliohms small. This video shows how to make a 4-wire measurement, prove when it is accurate, and alternatives to 4-wire. See below for an explanation of the alternative method shown. Behind the scenes Doing yet another DMM episode was a tough call for me. However, I am working on a project that requires me to characterize both a 1 ohm and a 100 milliohm resistor. The element14 community was kind enough to send me an MP720028 bench DMM. As shown in the picture, it has an extra set of banana jacks called “4-wire sense.” These connections make 4-wire resistance measurements. In this video, I show the same resistor measured with the traditional 2-wire and advanced 4-wire configuration. (Spoiler Alert! The 2-wire measurement was almost twice as big as the 4-wire!)

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Digilent Analog Discovery 2 Review | Workbench Wednesdays

Sun, 29 Dec 2019 18:44:50 +0000

The Analog Discovery 2 combines all the equipment found on a typical electronics workbench into one small package. It packs an oscilloscope, logic analyzer, power supplies, spectrum analyzer, and so much more. As impressive as the hardware is, the Analog Discovery 2’s software, called Waveforms, is fantastic as well. You can configure it for any measurement situation, and it has extensive scripting capability. See if you should be considering adding the Analog Discovery 2 to your electronics workbench.

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Function Generator Basics | Workbench Wednesdays

Sun, 29 Dec 2019 18:32:19 +0000

Generating signals with a waveform, function, or arbitrary generator lets you test all kinds of circuits. Learn how to get a function generator to output a signal, the 3 types of waveforms you can create, and which controls matter. James, the Bald Engineer, explains the difference between analog and digital generators. The video introduction is my first attempt at doing an LGR style “Tech Tales” story. It is short with only a few images. However, it is something I would like to do more of in the future. My professional career started at Agilent right when they split off from Hewlett Packard. Most of my co-workers had been there while Bill and Dave still worked at the company. Even though the computer division took the name, Agilent was HP’s core: test and measurement.

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Logic Analyzer Basics | Workbench Wednesdays

Sun, 29 Dec 2019 18:28:48 +0000

Logic analyzers capture digital signals and then display a waveform or list. Serial busses like I2C, SPI, or UART (Serial) can be decoded or triggered on when there are problems in your circuit. In this video, learn the basic controls you need to use (almost) any logic analyzer. You’ll learn how to set up a simple trigger, make measurements, and set things like sample rate or memory depth. When I first graduated from college, I started as an Application Engineer for Agilent Technologies. Based in Austin, I supported computer companies like Dell, Compaq, HP, IBM, and Tandem. I helped their engineers set up million-dollar logic analyzer configurations to measure various PC busses.

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Spectrum Analyzer Basics | Workbench Wednesdays

Thu, 17 Oct 2019 02:06:58 +0000

A spectrum analyzer displays signals in the frequency domain. To use one, you only need to know about four controls: reference level, center frequency, and resolution bandwidth. In this episode, see how to use a spectrum analyzer and determine the transmitting frequency of a device. The example device is my microphone transmitter. It operates around 500 MHz with FM modulation. You’ll see how I step through the spectrum analyzer controls to find the exact frequency. At the end of the episode, I show some advanced measurements you can do with a modern spectrum analyzer. My favorite one is the demodulation.

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DCA Pro Transistor Tester Review | Workbench Wednesdays

Wed, 07 Aug 2019 14:19:09 +0000

When it comes to transistors, there are only so many things a multimeter can measure. The DCA Pro from PEAK Electronics makes short work of testing parts like a transistor. This small device can determine pinout, component type, and essential parameters in a matter of seconds. Not only that but it can be connected to a (Windows) PC and draw parameter curves. Check out the video review to see how the device and software work. Then head over to the element14 page where you can download a zip file full of example parts I measured for you. Use the free DCA Pro software to open them.

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7+ Python Engineering Modules for Electronics Engineers

Thu, 11 Jul 2019 12:50:23 +0000

Python is everywhere. Its capabilities continue to grow. Not only can you create simple scripts, but you can create full-blown applications with it. The core has been scaled down to run on 32-bit microcontrollers like the ESP32 and Adafruit Feather M0. You can even use Python engineer modules to design stuff like circuits. There are electronics Python modules that create schematics, simulate circuits, and make solving math a cinch. Here are some of the modules I found that make Python usable for (electronics) engineering.

Hakko FX-888D Review

Wed, 03 Jul 2019 12:49:50 +0000

My friend Pablo recently upgraded his firestarter iron to a Hakko FX-888D. Because of its popularity and his relative newness to the iron, I asked if he’d like to write up a review for it. You can follow him on twitter. Just based on the color, the Hakko FX-888D seemed, at first, like it was a toy compared to other electronic tools and equipment. The color does make it easy to spot even if you are buried in a project. You can quickly find it because it stands out. The outside seems like plastic, but it is made from or encased in metal. Knowing that it was only a plastic enclosure made me feel like this will be with me for a long time.

Raspberry Pi 4 Armchair Datasheet Evaluation

Mon, 24 Jun 2019 18:45:38 +0000

With the introduction of the Raspberry Pi 4, I dug into the announcement and datasheet while waiting for mine to arrive. Well, “datasheet” might be an exaggeration, but there is a list of the Raspberry Pi 4 tech specs available. That link gives a bullet item list of the main specs. In this post, I focus on these four: Broadcom BCM2711, Quad core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz Up to 4GB LPDDR4-2400 SDRAM (depending on model) Gigabit Ethernet 2 USB 3.0 ports; 2 USB 2.0 ports. There is a lot of very cool stuff on this $35 board. (Amazing they have kept that price point!) Or even the 4 GB $55 board. Adding Bluetooth 5, H.265 AND H.264 decoding, USB-C connector (Power), and changing the SoC to a 28 nm process are all significant improvements.

Introducing Bit Preserve

Wed, 12 Jun 2019 18:13:01 +0000

A project I work on in my spare time is creating a portable Apple II. Like many of my projects, one leads into another. I started out wanting to make a mobile Apple II, and now I’m working on a project called Bit Preserve. How did I get from one project to the next? Well, as I looked into how to make a portable Apple II, I realized a significant issue. The original Apple II logic board has almost 80 ICs. Being a design from 1975, they are all through-hole packages. The good news is that except for the ROM chips, they are all off-the-shelf components. But such a size means it might be impossible to turn it into something handheld. I almost abandoned the project. Then, I learned about a chip included in the Apple IIgs. The name of the ASIC is “MEGA II.” (Nothing to do with Arduino.) It is a chip that integrates all of those off-the-shelf chips into an 84 pin package.

New Arduino Nano board from Maker Faire 2019

Wed, 22 May 2019 13:42:05 +0000

I had the chance to spend some time with the Arduino team before and during Maker Faire Bay Area 2019. I also attended Massimo’s “State of Arduino” talk. In short, there are new Arduino Nano boards coming, a certification available today, updates on the Vidor, interesting education kits, and one more special announcement. It rained most of the weekend, which I am sure caused attendance to take a hit. Normally this would not be a big deal, but there was some talk it may be the last year for the Bay Area’s show. As usual, I walked the show on Friday and did take note there were several new exhibitors throughout. For that reason, I hope it is not the last one.

6 things I learned about KiCad at KiCon 2019

Fri, 17 May 2019 18:26:00 +0000

In April 2019, hardware hackers, hobbyist, and engineers joined together for the first KiCon. A couple of people asked me, “why is there a conference for KiCad?” Some questioned if KiCad was significant enough software to warrant a conference. That question is valid. But KiCon is larger than the KiCad software. Even in its first iteration, KiCon evolved more into a meeting for people building electronics hardware from small scale hobbyist to professionally designed systems, than just a conference on a single piece of software. Some might call it a maker conference. I call it a hardware developer conference. The key that tied everyone together is the open source software behind our printed circuit boards.

Tenma 72-2660 Portable Hand Held Supply | Workbench Wednesdays

Mon, 13 May 2019 13:25:12 +0000

The TENMA 72-2660 portable power supply offers bench supply capability in a backpack-friendly package. The single output is capable of 45 watts with up to 30 volts and 3.75 amps out. The built-in USB ports offer an easy way to power 5 Volts Arduino or Raspberry Pi projects while limiting their current. See how this portable supply performs, the things the Bald Engineer likes about it, and the points to consider before buying

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Health and Solder Fumes | Workbench Wednesdays

Thu, 09 May 2019 13:18:20 +0000

An overlooked danger of electronics soldering is the fumes. While the smell and smoke may not be pleasant, the chemicals in the fumes can be harmful. Is solder made with lead(Pb) your only concern? Learn about where lead-free solder came from, what different flux types mean, and two ways to keep your air (and your lungs clean.) In the video, I show a cheap “smoke eater” and a professional fume extractor. There is a cost difference of $50 and $700 between the two. However, either is better than having nothing.

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7 MOSFET Myths and Misconceptions Addressed

Wed, 08 May 2019 13:03:24 +0000

The most popular AddOhms video is my short tutorial on MOSFET basics. In the years since I posted the video, people have sent me many questions. While answering those questions I’ve learned quite a bit as well. For example, in that video, I say that Vgs is the threshold to turn on the MOSFET. Well, it turns out, that is not entirely true. It is the threshold to turn it off! Oops. A minor point with a subtle difference, but a common MOSFET misconception.

Low side vs. High side transistor switch

Wed, 10 Apr 2019 13:45:02 +0000

A common task for a transistor is switching a device on and off. There are two configurations for a transistor switch: low side and high side. The location of the transistor determines the type of circuit and its name. Either transistor configuration can use a BJT or MOSFET. In this post, I draw the configuration for both transistor types, discuss which requires a driver, and explain why you would use either. If you are new to transistors, check out the resource links at the bottom. I have a few videos I made and some from element14’s The Learning Circuit, which do a great job introducing transistors.

Surface Mount Rework Tools | Workbench Wednesdays

Thu, 28 Mar 2019 03:21:42 +0000

In this element14 Workbench Wednesdays episode, I review tools provided by Weller which are suitable for surface mount soldering. Throughout the soldering series, I have been using mini-projects to see how the gear works. Making this particular video was special to me. The subject was a TI-85. Back when I was a kid, one of my first soldering projects was to replace a capacitor in the TI-85. At the time, all I knew is that the change would make it run faster. I didn’t know why I just knew it worked.

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Soldering Tool Upgrade Paths | Workbench Wednesdays

Sat, 09 Feb 2019 01:45:15 +0000

Right after the digital multimeter, or DMM, a soldering iron is a must-have tool for electronics work. Like most tools, there is a vast variety of options available. In this episode of element14’s Workbench Wednesdays, I look at a range of instruments from Weller. They offer everything from a cheap $10 “fire starter” (sorry, it is what we call them!) all the way up to a full-blown surface mount rework station. Whether you don’t have a soldering iron or you have a $100 station, this video will show you options to consider when thinking about an upgrade.

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Answering BJT questions with Karen on element14's The Learning Circuit

Wed, 02 Jan 2019 17:29:28 +0000

Over on element14, Karen hosts The Learning Circuit. It is a tutorial show geared towards learning STEM basics. So far she has covered subjects like soldering, diodes, and how to make a DIY electromagnet. She did a great job on introducing BJTs and how they work. While I thought she provided a clear explanation of the internal workings, some members of the element14 community still had questions. She invited me on to revisit BJTs and transistors to (hopefully) clarify the connection between how transistors physically work and how to use them.

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Connect pins with KiCad Bus, Labels, and Global Labels

Wed, 21 Nov 2018 14:18:20 +0000

2020-04-04: This tutorial is based on KiCad 5. With KiCad 6, the bus feature works a little different (so I’m told.) When your schematic has a large number of related signals, it is helpful to group them. In its schematic editor, KiCad has a few tools to help. Your end-goal helps determine which tools to use. For example, do you need a KiCad bus or a label? In this post, I explore how you can define signals, group them, and reference them across schematic sheets.

What is the Apple IIgs? - AddOhms Live Clip

Mon, 19 Nov 2018 14:04:01 +0000

During a live stream, I was asked: “What is the Apple IIgs?” In this AddOhms Live Twitch Clip, I answer the question. The Apple IIgs was the last of the highly successful Apple II line of computers. The “GS” stood for “graphics” and “sound.” Compared to previous Apple II computers, the IIgs was a fully 16-bit machine. When connected to its proprietary RGB monitor, it rendered a gorgeous display. Sadly, not much software took advantage of the improved graphics and sound capabilities. The IIgs was fully backward compatible with the older 8-bit line of Apple II computers. Its compatibility was so good that most IIgs users only used it in the compatibility mode.

Creating Custom KiCad Schematic Symbol in 5 Steps

Wed, 14 Nov 2018 14:21:23 +0000

A new project I have started working on involves the Apple IIgs. It was Apple’s last 16-bit (and 8-bit) computer. Inside are many application specific integrated circuits, or ASICs, that make the IIgs an extraordinary member of the Apple II family. One chip, in particular, is called the “MEGA-II.” This chip takes all of the individual logic chips from the original Apple II design and incorporates them into a single 84-pin PLCC.

Arduino millis() plus addition does not add up

Wed, 10 Oct 2018 13:00:23 +0000

In the past, I’ve covered how to reset Arduino millis() and have provided a growing list of examples using millis(). While reviewing the code for the elegoo Penguin Bot, I was reminded of a millis() mistake I see often: addition. The only way to properly handle millis() rollover is with subtraction. Let’s look at why (and how.) What is Arduino millis() The Arduino library has a function called millis() which returns the number of milliseconds the processor has been running. On other platforms, you might see references to a “tick counter.” It is the same idea. A hardware timer keeps incrementing a counter at a known rate. In this case, that rate is milliseconds.

Arduino MKR Vidor 4000 Hands-On

Wed, 15 Aug 2018 13:27:52 +0000

Earlier this week, I looked at the Arduino MKR Vidor 4000 during an AddOhms live stream. My goal was to understand the Vidor better. It is the new FPGA-based Arduino which started shipping this month. It runs about $60. You can learn more at the Vidor Product Page on the Arduino website. In this post, I briefly touch on the difference between an FPGA and a microcontroller. Then I walk you around the MKR Vidor 4000’s board. Using one of the examples, I talk a bit about how the various chips communicate with each other. This section also highlights what makes the Arduino FPGA board different from other development boards. Lastly, I answer “should you buy an Arduino MKR Vidor 4000?”

Standalone Arduino Turn-On and Debug

Mon, 09 Jul 2018 13:00:54 +0000

This AddOhms episode is part 3 of the “design your own Arduino” series. In this one I populate a bare PCB, reflow solder it, debug a few issues, and load the Uno bootloader. Originally, I designed 2 versions of the board. One version contained an error that I planned to fix in the episode. Well, turns out, the “correct” board had two issues which were more interesting. Check out the #27 show notes for links to a bunch of stuff in the episode, including the design files.

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Five Arduino math fixes for when it is wrong

Wed, 04 Jul 2018 13:16:52 +0000

While the Arduino library does an excellent job of hiding some of C/C++’s warts, at the end of the day, it is still just C/C++. This fact causes a few non-intuitive issues for inexperienced programmers. When it looks like Arduino math is wrong, it is probably one of these reasons. When people ask me for help with their programming, I check each of these Arduino math mistakes. If your code seems to be hitting a bug, check to make sure it is not how the compiler handles math.

Arduino EEPROM stores any datatype

Wed, 20 Jun 2018 13:00:46 +0000

Funny how a simple idea can spider out into multiple paths. Arduino EEPROM seemed like a straightforward concept. A few a years ago it was as easy as having either 512 or 1024 bytes of flash memory. The Arduino IDE offered an EEPROM library which let you read and write a single byte. Today, however, with many different processor architectures saving data to EEPROM varies. It is now possible to save any datatype to EEPROM but not on all boards and not all using the same method.

Learn Six Oscilloscope Measurements with an Arduino DUT

Wed, 13 Jun 2018 18:44:22 +0000

One of the best ways to learn how to use a new piece of test equipment is to use it. Sounds easy, right? The problem is, sometimes when you are in the middle of troubleshooting your circuit, figuring out what the knobs on your scope do is an immense frustration. Use these 6 oscilloscope measurements, and just an Arduino Uno, to learn how to use a new or unfamiliar digital scope.

5 LDO Regulator Considerations other than voltage and current

Wed, 30 May 2018 13:03:28 +0000

For an AddOhms series, I created a DIY Arduino I am calling the “Pyramiduino.” It is an ATmega328p based board in the shape of a triangle. Other than being cute, the shape does not offer any other benefit. The design features a 3.3 volt LDO Regulator, which is also the subject of this post. I forgot a fundamental aspect of design: read the freaking datasheet. The board’s LDO regulator was not turning on. Adding a passive scope probe to the circuit suddenly fixed the problem. The regulator turned on. When touching the enable pin, it measured about 1.25 volts. While I am sure Rohde & Schwarz would like me to ship scope probe with each board, that was not an option. With the impractical fix in place, I got to thinking about that voltage level. I remembered that the datasheet mentioned about 1.2 volts was needed for the “HIGH” threshold. Which meant, 1.25 volts applied to the pin enabled an active low input. Not only that, I remember the datasheet clearly said it had a pull-down resistor built-in. What was going on?

Creating an AddOhms Animations - Behind The Scenes

Mon, 28 May 2018 13:00:05 +0000

Pretty often I am asked about how I create the AddOhms animations. Currently, I’m working on the final part of the DIY Arduino Series. In the first part, I showed the elements of an Arduino schematic. The second part showed an overview of the PCB design. Finally, I will take the finished board and explain how to turn it on the for the first time. Lucky for me, there was a “mistake” on the board. This error gives some context for the episode.

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Maker Faire 2018, Bald Engineer's Highlights

Wed, 23 May 2018 18:54:34 +0000

The Bay Area’s Maker Faire 2018 encompasses an impressive scope of activities. Pedal-powered live music, fire-breathing machines, kids building stuff, corn dogs, fresh honey, LEDs, soldering, roaming robots, and so much more. The last couple of days I made a few posts on the things I saw at Maker Faire. In this post, I’ll summarize many things that don’t fit together, but I wanted to mention that I enjoyed seeing.

Bay Area Maker Faire 2018 Photo Gallery

Wed, 23 May 2018 17:57:41 +0000

With the Bay Area Maker Faire over, I’m wrapping up my coverage with a photo gallery of my favorites. Some of these have been covered in my other Maker Faire 2018 posts. So check those out for details. FYI. Some of the products in this gallery will be covered in future posts. Maker Faire 2018

5 Unexpected Brands at Maker Faire 2018

Tue, 22 May 2018 19:51:28 +0000

Maker Faire, like any festival, is a combination of passion products, startups, and larger companies generating awareness. As I walked around, I noticed many logos and brands. An obvious one to see is Make Magazine. Another I saw that made sense is Digi-Key’s maker.io. They had a strong showing, along with the Arduino booth. But that one is expected since so many projects, not just electronics, have an Arduino in them. That said, there were five brands that I did not expect to see at Maker Faire (and most had something interesting to show.)

Arduino Uno WiFi Rev 2 Features I noticed

Tue, 22 May 2018 02:10:34 +0000

Arduino announced several new products at the 2018 Bay Area Maker Faire. One of those products is the Uno WiFi Rev 2. (Check out this post for an introduction to the MKR Vidor 4000, an FPGA-based board. You can read their official announcement here. This new Uno board represents a significant upgrade for the 8-bit family of Arduino boards. However, I do have a few reservations. Arduino Uno WiFi Rev 2 Starting off, I am not happy with the name. It is too long. For that reason, I am going to keep using the full name in this post to demonstrate why I don’t like it. Another reason I’m grumpy it that new microprocessor makes it incompatible with 328p code. That said,sketches (and libraries) using only the Arduino library will (likely) work fine. Anything that uses registers, like direct port manipulation, will have issues. Just like moving to any other architecture supported by the IDE. However, because it has the name “Uno,” many users will be tripped up by incompatibilities.

MKR Vidor 4000 brings FPGA to Makers

Mon, 21 May 2018 21:44:26 +0000

Arduino announced several new products at the 2018 Bay Area Maker Faire. One of those products is the MKR Vidor 4000, an FPGA-based board. You can read their official announcement here. (Over here is a write-up on the new Uno WiFi Rev 2.) The goal of the MKR Vidor is to make FPGA accessible to makers and innovators. It represents a new shift in hardware focus for the Arduino team. An FPGA is a Field Programmable Gate Array. In other words, it is reconfigurable hardware. Unlike a microcontroller, an FPGA is not running software. Instead, its gate array changes configurations for a specific task.

Oscilloscope Probes Primer - Why so many types?

Wed, 02 May 2018 22:06:58 +0000

Unless you have a BNC or SMA connector your board, you will need a probe to get signals into an oscilloscope. Understanding what kind of oscilloscope probes are out there, which ones should you have for your scope and which ones to use for different measurements can be daunting. In this post, I look at some common scope probe types and offer some suggested measurements for each. Special thanks to Rohde and Schwarz for providing the equipment used in this post. You can learn more about their scopes and probes at rohde-schwarz.com . This post is not a comprehensive guide of oscilloscope probes. I am covering the types I have used. I do think this information should be enough to least form questions to ask your vendor before purchasing. Asking questions is important. If you have never bought specialized oscilloscope probes, you might not realize they can cost more than the scope itself. Maybe not an individual probe, but get one for each channel, and the cost rises. So picking the correct probe type is essential.

EAGLE 9 First Look - Couple of things I noticed

Wed, 25 Apr 2018 13:00:21 +0000

Autodesk released EAGLE 9. This new version continues the improvement that Autodesk has been providing since acquiring the infamous ECAD tool. There are three areas I look at in this AddOhms Livestream. How I looked at EAGLE 9 In the beginning, I use an old training class I wrote about five years ago when I was using EAGLE daily. It shows how to design a 555 flashing circuit from schematic to PCB. A follow-on class taught how to mill the PCB on a Shopbot. I might update the course and release it if I have time. The exercise class helps me find some surprises with EAGLE’s incremental improvements.

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FPC1500 Review, a Rohde & Schwarz Spectrum Analyzer

Wed, 04 Apr 2018 13:00:15 +0000

Everyone’s first piece of test equipment should be a multimeter. Next is probably a power supply with current limiting. For many engineers, the next step is an oscilloscope. At least those working on digital electronics. Even if you are not working with RF, do not overlook a spectrum analyzer. The Rohde & Schwarz FPC1500 is three instruments in one: a Spectrum Analyzer, RF Signal Source, and a Vector Network Analyzer. In this post, I combine an FPC1500 review with an introduction to these frequency domain tools.

IoT: Intelligent Outsourcing

Wed, 28 Mar 2018 20:37:14 +0000

Whether you are developing a WiFi-enabled coffee maker, a sensor to detect rainfall, or a livestock tracking drone, an IoT device will follow the same product development cycle. A common mistake that engineers will make is trying to own the development at each stage, at least up until “deliver.” Who can blame us? The idea of delegating any part of our new product introduction can be daunting. Delegating, or outsourcing can be a powerful tool. It allows you to focus on the elements of your process that only you can do. Let others handle the rest. If your core contribution is the machine learning algorithm, then focus your effort there. Spending time designing the enclosure, or negotiating with suppliers, or even laying out the printed circuit board is a waste. Let the people who excel in each of those areas apply their expertise to your product.

DIY Arduino PCB Pryamiduino (Video)

Wed, 28 Feb 2018 14:00:03 +0000

Continuing the DIY Arduino tutorial series, this AddOhms episode shows how to create a PCB in KiCad. I make a joke that the original design was a rectangle, which I found boring and pointless. So instead, I designed a triangle to give the board 3 points. Get it? Puns! I am calling it the Pryamiduino. To be honest, I found not having a constraint to be a problem. By forcing a specific board size and shape, many decisions were more manageable.

Debug SONOFF AC Relay with a Thermal Camera

Thu, 22 Feb 2018 03:43:36 +0000

My recent SONOFF WiFi Switch experience reminded me of something from high school. I attended an off-site electronics class with my best friend. As teenage boys, we were prone to doing stupid things. One of our favorite games was to see who could handle the highest voltage. Our bench had a variable AC supply that went from 0 to 120 volts. So we would grab the alligator clips while the other person slowly turned the knob up. John once made it to 50 volts. I seem to recall my tolerance around 30 volts. First, DO NOT do this. It was stupid. Second, I think this game is why handling AC makes me so uncomfortable.

Circuit Python adds Python to Microcontrollers

Wed, 14 Feb 2018 14:57:09 +0000

Back in 2013, a Kickstarter ran for a project to put a python interpreter on a microcontroller. At the time I could not see the benefit. Cool project, but I asked myself: “why?” On my last Adafruit order, I received a free Circuit Playground Express. The board comes with CircuitPython pre-installed. After playing with Circuit Python, or CP, I finally “get it.” For Valentine’s Day, I made an animated LED heart for a new love in my life, Circuit Python. Well, love is a bit of a strong word. The past couple of weeks I have been l earning Circuit Python, and I am excited by what it offers.

Hologram.io connects Adafruit FONA

Thu, 08 Feb 2018 03:00:18 +0000

While the buzzword “IoT “is relatively new, there has been a long time “internet of things” in operation. Those devices are called the far less sexy term “M2M” or machine-to-machine. These devices, around since the 90s, contain a microprocessor, some sensors, sometimes electromechanical hardware, and a cellular radio. These M2M devices were (and still are!) the early “Internet of Things.” Thanks to Hologram.io, you can join this new/old trend for free.

Signetics Write Only Memory 25120 Datasheet

Tue, 06 Feb 2018 20:18:37 +0000

Signetics started as an IC manufacturer. In 1975 they were bought by Philips Semiconductors, which is now NXP. Interestingly the address in the datasheet, I think, was the original site. Today, it’s home to a Lowe’s Home Improvement Store. According to this Wikipedia article, it was created by John “Jack” Curtis. Apparently, it was included in a real Signetics catalog as a joke! Imagine that happening today. Additional information about the joke is available on sigwom.com. (Which may be written by Jack himself, not entirely sure.)

Adafruit Feather Review and Selection Guide

Wed, 24 Jan 2018 14:04:17 +0000

Four days ago, I found out I needed to make a piece of a costume. The idea was to combine a TFT LCD with a microcontroller and Bluetooth Low Energy. I checked my microcontroller bin and found some Adafruit Feather Boards. In this post, I will introduce the feather family and provide a decision chart for choosing the right one for your project. adafruit-feather-layout The Feather board have a standard footprint and pinout. Most(All?) have a USB connector, a microcontroller, two rows of pins, and a battery charger. They measure 50.80 by 22.86 mm, which is 2.0 by 0.9 inches.

DIY Arduino Schematic board and Checklist

Wed, 17 Jan 2018 14:00:18 +0000

One of the last significant steps in a project is designing the custom PCB. This stage means creating a DIY Arduino board that is custom to the application. Two examples of my past projects are BinBoo, a Binary Clock, and Open Vapors, my reflow oven controller. While working on a project for a friend, I got to thinking; it would be nice to have a checklist for circuit elements to include on a DIY Arduino board. In the early days, I forgot to add a filter cap to AREF, for example.

What is the Bald Engineer doing?

Wed, 10 Jan 2018 19:37:46 +0000

The next AddOhms Tutorial is how to design a DIY Arduino board. What are the elements you need to include in your own circuit design? While editing the video, I ended up on this frame. It looked to me like I was praying. (At one point I was having serious technical issues with my equipment. But it is unrelated to that frame!) On Twitter, my friend Philip had a different take.

2017's Best Bald Engineer Tutorials, Articles, and Reviews

Wed, 27 Dec 2017 17:45:25 +0000

As 2017 comes to a close, I looked back to see what readers made the most popular. It was an exciting year. The Arduino family came back together, Adafruit trolled the internet with rumors of a RadioShack buy out, and for me, I changed jobs. Project wise I got my RetroPie SNES build completed, using an old Super Famicom case. This case is one I bought in Japan for 500 yen (about $5.) This work also led me to discuss voltage divider circuits. And I looked at a couple of scopes.

7 Arduino LCD display tips and tricks

Thu, 21 Dec 2017 17:30:03 +0000

When I started working on Open Vapors, I thought the stumbling point would be the PID algorithm or safe AC line control. However, it turned out; I spent a significant amount of time understanding how to print to the Arduino LCD display correctly. If you need an easy to use RGB LCD, check out the Grove LCD from SeeedStudio. They sent me one to check out. The LCD comes with Seeed’s “grove connector system” which can connect to a variety of their Arduino-compatible boards. You can also pick up the Grove Base Shield which adds a variety of Grove connectors to an Arduino Uno. The Grove LCD makes it super easy to connect up a character LCD. It is very plug-and-play.

Arduino Keyboard Matrix Code and Hardware Tutorial

Fri, 15 Dec 2017 14:00:26 +0000

As a kid, I got the book " Upgrading and Repairing PCs." (Now in its 22nd edition.) It was the first book to explain to me the PC architecture. I considered, how were there so few pins on an AT-style keyboard connector when there were 101 keys on the keyboard? That is when I first learned about the keyboard matrix. Intel_P8049_AH_controller The keyboard matrix itself did not amaze me, but instead the idea there was an entirely separate 8-bit microcontroller inside of the keyboard. Early keyboards may have used the P8049AH, which, there is still some stock available to purchase. I was fascinated with the idea an entire computer was necessary to run the keyboard, to use my “real” computer. Why did it take something as complicated as a microcontroller?

Open Source Hardware Summit 2017 Recap

Wed, 01 Nov 2017 13:41:04 +0000

This year Denver hosted the 2017 Open Source Hardware Summit. It’s a one-day seminar with talks, demos, and a couple of drinks. The day after the official show Sparkfun and Aleph Objects hosted tours of their facilities. The combination of events made for a fantastic immersion into open source hardware. There were many talks and demos setup during the summit. Here are three that caught my attention. Please note, this is not to rate or judge the quality of anyone’s work. Simply, a couple of weeks later these are the three talks that stuck with me.

Aluminum Polymer Capacitors on EE Journal's Chalk Talk

Mon, 30 Oct 2017 22:38:05 +0000

What are aluminum polymer capacitors? These are a solid type of capacitor that replaces the liquid electrolyte with a solid polymer material. Sometimes you might hear these capacitors called “organic aluminum.” Technically, they are still “electrolytic” capacitors. However, the colloquial term of “aluminum electrolytic” refers to the traditional wet electrolyte-based capacitors. In this video, I meet with Amelia Dalton of EE Journal, and we discuss these capacitor types. Mouser and EE Journal developed the video in joint with KEMET. (Previously I talked on Amelia’s Chalk Talk about SSD Capacitors.)

Watch this video on YouTube

FleaFPGA Ohm is a crowdsource project worth considering

Wed, 04 Oct 2017 13:31:38 +0000

Previously, I wrote a FleaFPGA Introduction. This board was about the size of an Arduino Uno with some GPIO pins, a VGA, USB, SD Card, PS2 Style Port, and a USB Host connector. At the time, the Lattice Mach XO2 provided the base logic. It found some success in the emulation community (*cough* x86 *cough*.) Unlike software emulators, the FPGA emulates the actual digital logic of classic computer ICs. Also known as ASICs.

Op Amp Circuits by Bob Pease

Wed, 27 Sep 2017 17:45:07 +0000

Op amps are one of the most versatile ICs in electronics. A purely analog device, they can be used for amplification, summing, integration, and a whole host of other circuits. AN-31 from Texas Instruments is 32 pages of op amp circuits. (Note: this document was created before TI acquired National Semiconductor.) Even more amazing is that the author is Bob Pease. If you never heard of Mr. Pease, please spend a few minutes right now reading this TI page dedicated to him. His contributions to electronics are nearly immeasurable. (Sadly, he was involved in a car accident after attending the funeral of his equally famous engineering friend, Jim Williams.)

Zener diode makes for a lousy regulator

Wed, 20 Sep 2017 12:57:08 +0000

The Zener diode is often used to create a reference voltage. In tutorials and even college texts, there are mentions of creating a Zener diode based regulator. The idea is that the Zener maintains a known voltage drop. The problem is that current matters. This post looks a quick Zener diode overview and shows what happened when I tried to power a microcontroller using a “Zener diode regulator.” Zener diodes overview Just a brief overview if you are not familiar with Zener diodes. Like typical diodes, Zeners have low forward voltages. Typically you voltages are around 0.7. However, different material sets can offer different forward voltages.

PicoScope 2204 Review and Hands-On

Wed, 13 Sep 2017 12:21:32 +0000

If you need a reason to be an Element 14 member, let me suggest their Road Test program. Companies partner with Element14 to get people to try out their gear. A couple of years ago I got a new microcontroller board. This week I received a new test instrument. Here’s my hands-on Picoscope 2204 review. The scope is bus powered. With the BNCs and type-B USB connector, it is slightly larger than an external USB hard drive. There is not much weight to the device. It does not feel cheap, just lighter than I expected.

5 Voltage divider circuits that go beyond dividing

Wed, 23 Aug 2017 13:19:15 +0000

Hey Newsletter Readers: Looking for Best Resistor Sorting Method? My Bad! Here are some ideas of what you can do with the humble voltage divider. This elementary circuit has a few inventive uses. To be upfront, one of these uses is NOT as a voltage regulator. If you need a voltage regulated, get a voltage regulator! At some point or another, I’ve built all five of these voltage divider circuits. For me, the voltage level shifter is the most common.

Pi Cap Hands On Review

Wed, 16 Aug 2017 13:05:52 +0000

The Pi Cap adds capacitive touch buttons to your Raspberry Pi. Bare Conductive was kind enough to send me one. I do not have a project in mind right now, so here are my first impressions. What is the Pi Cap? Arduino tends to call daughter cards shields, while the Raspberry Pi community calls them hats. The Pi Cap is a hat. It plugs into the GPIO header of a Raspberry Pi and provides 13 capacitive touch pads. There is a traditional push button, an LED, and a prototyping area. While the Pi Cap does consume all of the GPIO pins, several are broken out near the GPIO header.

Aeroscope Review

Wed, 19 Jul 2017 13:11:36 +0000

Previously, I reviewed the smartphone DMM, Mooshimeter. It is a great meter. One feature I didn’t spend much time on in my review was the ability to graph. Some see it as an “oscilloscope alternative.” The past couple of weeks, I’ve been using Aeroscope. It is a Bluetooth-based oscilloscope about the size of an older active probe. The Aeroscope runs $199 direct from Aeroscope Labs. The question I address in this Aeroscope review: is it better to buy this, a USB-based, or standalone scope for about the same money. How does it measure up?

PWM a 3-pin PC fan with an Arduino

Wed, 05 Jul 2017 13:13:53 +0000

A question came up on IRC regarding how to PWM a 3-pin PC fan with an Arduino using analogWrite(). Controlling the fan was seemingly straightforward. The problem was that the hall effect sensor, or TACH signal, was incredibly noisy. The noise made it impossible to measure the fan’s rotation. Working through the question, I found three issues to tackle: You need to use a PNP transistor Filter capacitors help Create a non-blocking RPM measurement (with millis()) This post addresses all three issues regarding how to PWM a 3-pin PC fan with an Arduino.

Raspberry Pi Startup Script Tutorial

Wed, 28 Jun 2017 13:03:46 +0000

The last couple of weeks I have been making progress and posts on my RetroPie build. I’m putting a Raspberry Pi inside of an actual SNES (well Super Famicom). Part 1 covered the schematic for a Soft Power Controller. In Part 2 I broke down the RPSPC state machine. This 3rd and final post of the series is a Raspberry Pi startup script tutorial. It covers how to make scripts run at startup and shutdown.

Soft Power Controller State Machine

Wed, 21 Jun 2017 13:00:43 +0000

Previously I looked at the hardware needed to build a Raspberry Pi soft power supply. This week I’m looking the state machine for the microcontroller. Why is such a complicated circuit necessary? I am replacing a Super Famicom (SNES) motherboard with the Pi. The trick is, I want to use the original power switch to turn the Pi on and off. This requirement presents a problem. When the switch goes into the “OFF” position, power needs to stay on long enough for the Pi to properly shutdown. So the switch itself can’t provide power to the Pi directly. With minor changes, the code in this state machine could be made to work with push buttons as well. If I add that feature in the future, I’ll update the code on the RPSPC GitHub project.

Raspberry Pi Soft Power Controller - The Circuit

Wed, 03 May 2017 23:18:56 +0000

The RetroPie project enables retro-gaming with a Raspberry Pi. All of the Pi models have enough computing power to emulate the major 8-bit and 16-bit computers of the 80s and 90s. With the Pi 3 I have even been able to play PS1 games with no problem. My current project is to put my Raspberry Pi running RetroPie into an old Super Famicom (SFC), or SNES, case. The catch? I want the original SPST power switch to work. And by work, I mean allow the Raspberry Pi to shutdown properly when the switch goes into the off position. To accomplish this task, I am building a Raspberry Pi soft power controller.

Share projects on one of these 4 platforms

Wed, 26 Apr 2017 13:00:54 +0000

Sharing is the maker community’s foundation. When you share projects with others, you contribute to the community. In the past, you might just post your project on a personal website. Today there are many options to share projects. This weekend I “finished” my reflow oven controller, Open Vapors. Believe it or not, five years ago there were not a bajillion similar projects. In fact, I based my design on the only completely open source project I found. It is a reflow oven controller Arduino shield from Rocket Scream.

Detect short and long button press using millis

Wed, 19 Apr 2017 12:00:48 +0000

To detect a short and long button press using millis can give your project more functionality without adding more buttons. In this line-by-line example, I show how to react to a user pressing a button for a short period (100ms) or a long period (over 500ms). My example changes the blink rate of an LED on short presses. A long button press turns off the LED. In the code, I make use of a struct so that a single variable can be used to track multiple parameters. The benefit of this method is that adding multiple buttons is easy. You could create an array of these tyepdef’d variables.

7805 is at the heart of a Super Famicom / Super NES

Sun, 16 Apr 2017 00:37:01 +0000

When I made the AddOhms Tutorial on Linear Regulators, I made a comment about the 7805. I said it may be one of the most important Integrated Circuits (ICs) ever made. That’s a bold statement. The 555, 805, or 7400 might all qualify for such a distinction. My feeling about the 7805’s importance is because it is a chip that is still popular today. It is used, or at least was used, in so many applications. And it is the heart of many 5V digital systems.

Best Sorting Resistors Method

Wed, 12 Apr 2017 13:00:51 +0000

When you buy a grab bag of components, you might need to tackle sorting resistors. Here’s how I sorted some bags of random resistor assortments last week. Objectives Then method I use for sorting resistors achieves these objectives: Fewer Bins. It doesn’t take long to create a large matrix of resistor values. My resistor sorting method is relatively compact. Quick to find. When I’m building up a circuit, I don’t want to spend time sorting through a pile. Once I know the value I need, I find a single package and then look for a single color band. Works with 4-band and 5-band resistors. Let me be upfront: I *hate* 5-band resistor color codes. While the 5th ring is supposed to be slightly offset, or wider, or a different type of color; it doesn’t matter. It’s nearly impossible to tell read a 5-band resistor color code when they are in a pile. However, using my method for sorting resistors, it doesn’t matter if I’m looking at a 4-band or 5-band resistor. I can immediately identify the resistor value. Based on #3 alone, you might be wondering what is the fantastic method (and how much will it cost to get it!) Here’s the basics of my method for sorting resistors. (For FREE!)

Arduino Data Logger: Serial Monitor Alternatives

Wed, 05 Apr 2017 13:00:56 +0000

The Arduino serial monitor is usable when you want to watch data from an Arduino. However, it does not have a built-in method for saving the data. Here are some ideas if you want to build an Arduino data logger with or without a PC. Important note on Arduino Data Logger examples With all of these examples, please remember that whenever you open the Arduino’s serial port, the board will reset. So if your log file shows “Initializing SD card…” with a few data lines in between, it is because there is a reset happening.

Sending simple serial commands to an Arduino

Wed, 01 Mar 2017 15:00:16 +0000

Sending simple serial commands to an Arduino is the easiest way to communicate between an Arduino and a computer. The computer could be a PC, a Raspberry Pi, or any device that communicates with serial. By sending and “decoding” a single character it is easy to add a simple debug menu or even serial menu. Plus, it is easy to extend. Single Character vs. Full Words The mistake I see many people make is that they try to send full-text strings as serial commands. For example, to turn on a LED, I have seen (silly) commands like “RED LED ON” or “RED LED OFF.” While you could use something like strcmp(), as I showed on the Multiple MQTT Topics example, that tends to be overkill for most serial commands.

Multiple MQTT Topics with Arduino PubSubClient

Wed, 01 Feb 2017 13:00:22 +0000

In my Arduino MQTT Examples, I kept things simple by only subscribing to a single topic. One of the strengths of MQTT is that a device can subscribe (or publish) to multiple topics. The broker will sort things out. Even though my first example only showed one, it is straight forward to get the Arduino PubSubClient library to subscribe to Multiple MQTT topics. The quick answer is that you need to look at the MQTT response to find out which topic sent the payload.

2016 Great Year for Enginerds

Wed, 04 Jan 2017 14:01:49 +0000

While many want to call 2016 the worst year ever, I feel that is an entirely undeserved title. It certainly could have been a better year, but it wasn’t the worst that I can remember. For the engineering community, both professional and hobbyist, it seems to have been a fantastic year. My gauge for this feeling is the activity on baldengineer.com. In 2016, I saw almost half a million sessions contributing over 1.2 million page views. (That’s 98% more people looking at 313% more tutorials compared to 2015.)

Ripping apart soda cans with an Electromagnet

Fri, 23 Dec 2016 15:31:09 +0000

ArcAttack is a band that performs at the Bay Area Maker Fare, among other places. They feature massive signing Telsa coils. (Here’s a video I show when I saw ArcAttack in 2013.) Singing Telsa coils are awesome. Everyone knows that. Which is why I found when Dianna Cowern, the Physics Girl, visited the band ArcAttack, electromagnets are just as cool. In addition to talking about their music, ArcAttack’s Joe does something amazing. He splits an aluminum soda can with just an electromagnet.

Watch this video on YouTube

Wolfenstein 3D on Gameboy Color

Tue, 20 Dec 2016 15:00:41 +0000

Wolfenstein 3D defined the FPS genre in a way no one could have predicted. Just like the Gameboy defined portable gaming in a way no one could have predicted. Cartridge based computing and gaming offered something that disk (or disc?) based media never could: additional hardware.

If the Moon Were Only 1 Pixel

Mon, 19 Dec 2016 17:41:43 +0000

A tediously accurate scale model of the solar system When I was growing up, I watched a lot of Star Trek. Over time I’ve looked into other Sci-Fi series. The occasional hit, like the reimaged Battlestar Galactica, caught my attention. But, for me, the voyages of the Enterprise defined “space” to me. Or the stories on Deep Space Nine. (There are no other Star Treks.)

Mooshimeter Review - Smartphone Multimeter

Wed, 07 Dec 2016 17:23:41 +0000

For fifteen years I used my Radio Shack 22-168A digital multimeter as my go-to meter. A couple of years ago I bought a Fluke 115. Not because the RS meter lacked a measurement, but because I wanted a backlit screen. Here’s the crazy thing though in 20 years of multimeter development, there hasn’t been much innovation. Well outside of maybe auto-ranging. All three meters I have, plus the Virtual Bench I reviewed about a year ago all continue to have the same limitation: they can only perform one measurement at a time. That’s one feature that makes my latest meter, the Mooshimeter, unique. It can measure both voltage and current at the same time. Oh, and it doesn’t have a screen.

Fading LED: analogWrite millis() Example

Wed, 23 Nov 2016 14:34:21 +0000

It’s a well-known fact of engineering: LEDs make everything look better. And that means a Fading LED is even better. Using Arduino’s analogWrite(), fading a LED is just a matter of a loop. If you use delay(), you can’t easily add other actions. What can you do? Well, Fading a LED with millis() is pretty simple. Here’s the code to do it and a quick explanation. //pwm-fade-with-millis.ino // Example Fading LED with analogWrite and millis() // See baldengineer.com/fading-led-analogwrite-millis-example.html for more information // Created by James Lewis const byte pwmLED = 5; // define directions for LED fade #define UP 0 #define DOWN 1 // constants for min and max PWM const int minPWM = 0; const int maxPWM = 255; // State Variable for Fade Direction byte fadeDirection = UP; // Global Fade Value // but be bigger than byte and signed, for rollover int fadeValue = 0; // How smooth to fade? byte fadeIncrement = 5; // millis() timing Variable, just for fading unsigned long previousFadeMillis; // How fast to increment? int fadeInterval = 50; void setup() { // put pwmLED into known state (off) analogWrite(pwmLED, fadeValue); } void doTheFade(unsigned long thisMillis) { // is it time to update yet? // if not, nothing happens if (thisMillis - previousFadeMillis >= fadeInterval) { // yup, it's time! if (fadeDirection == UP) { fadeValue = fadeValue + fadeIncrement; if (fadeValue >= maxPWM) { // At max, limit and change direction fadeValue = maxPWM; fadeDirection = DOWN; } } else { //if we aren't going up, we're going down fadeValue = fadeValue - fadeIncrement; if (fadeValue <= minPWM) { // At min, limit and change direction fadeValue = minPWM; fadeDirection = UP; } } // Only need to update when it changes analogWrite(pwmLED, fadeValue); // reset millis for the next iteration (fade timer only) previousFadeMillis = thisMillis; } } void loop() { // get the current time, for this time around loop // all millis() timer checks will use this time stamp unsigned long currentMillis = millis(); doTheFade(currentMillis); } Global Variables for Fading LED Constants The constant “pwmLED” is the pin that gets faded. (Make that pin supports analogWrite().) The two #define statements, UP and DOWN, are simple states for the LED. They make the code easier to read. The “maxPWM” value is set to 255 for 8-bit AVR boards like the Uno. If you’re using the ESP8266, set this value to 1023. (You can also use the constant “PWMRANGE.”)

Insert Caption Here

Tue, 22 Nov 2016 17:38:12 +0000

Took this screenshot while I waited for the AddOhms Q&A #02 Video to finish rendering. What could I be pondering? (If this site still had comments, I would say leave it here…)

Electron Microscope Analyzing Vinyl Records (and other Spinning Media)

Mon, 17 Oct 2016 13:57:56 +0000

Ben Krasnow from Applied Science on YouTube uses his Electron Microscope to compare spinning media. The part of the video that caught my attention is the Vinyl Record. Not only does he show the groove and needle, but he puts it in motion! It’s a great look at how this technology works. Additionally, I loved how he went into detail about how to prep the record for use in the electron microscope. (Spoiler: he had to make the record and needle conductive.) After the vinyl, he also compares a CD and DVD. The twist is that he also shows how a Capacitance Electronic Disc (CED) compares to the vinyl. You never heard of a CED?

Watch this video on YouTube

Neil deGrasse Tyson's 4th Nerdist Interview

Thu, 29 Sep 2016 13:17:49 +0000

You are probably familiar with Neil deGrasse Tyson. He is as brilliant as he is entertaining. That fact is why I was so excited when I saw his name pop-up on my queue for the Nerdist Podcast. Nerdist Podcast In the past, I suggested some electrical engineering podcasts. The Nerdist isn’t like those. Hosted by Chris Hardwick, each episode includes an interview. As the podcast’s name suggests, most of the guests have some roots in today’s nerd or geek culture. So while not an engineering podcast, there may be the occasional guest that interest you.

Measure PWM Current with a Modified Moving Average

Wed, 28 Sep 2016 13:00:16 +0000

Pulse Width Modulation (PWM) makes it possible to dim lights, control the speed of motors, and (with the help of filters) generate analog reference voltages. When measuring the voltage or current of a PWM signal, there are unique challenges. You can use this tutorial to measure PWM current with a modified moving average (MMA). As I’ve mentioned in a few posts, I’m working on an RGB LED IoT controller. Soon I’ll post some detailed information on that. In the meantime, one choice I made was to include an INA219 current sensor on the LED power supply. For prototyping, I’m using the Adafruit Breakout Board, but my final design uses the same parts integrated into a custom PCB.

Brushed DC Motor Video Tutorial

Sat, 17 Sep 2016 16:36:39 +0000

How a Brushed DC Motor works and how to use them This Addohms Electronics Motor Tutorial goes into the third dimension. Using a 3D model, we show what makes a brushed DC motor, well, a “brushed motor.” (Hint: It’s the brushes!) Then, as usual, we break down two simple ways to control them with a microcontroller like the Arduino. You can use a single BJT Transistor (remember those from #10?), build a discrete H-Bridge to go in both directions, or use a popular H-Bridge chip like the L293D or L298D. (Notice the ‘D’!)

Watch this video on YouTube

Social Media Guide for Engineers, a How-To

Wed, 14 Sep 2016 13:48:45 +0000

Bloomicon / Shutterstock.com Engineers are notorious introverts. An untrue generalization is that introverts hate being social. Like all humans, introverts are social creatures. We just prefer only to discuss the topics which are of interest to us. We will listen to anything. This social media guide for engineers explains why and how you can participate in social media, without being social. Let’s address something head-on. Gone are the days of just “here’s what I ate” or “I’m in the bathroom” social posts. Social media channels are mature platforms for communication. Sure, junk still exists. However. You can filter out the signal from the noise when you following my social media guide for engineers.

3D Printer Tips I wish I knew 3 years ago

Wed, 31 Aug 2016 13:00:48 +0000

While I bought my 3D printer a couple of years ago, in March of this year, it only had 75 hours of use. Since March, my counter is over 300 hours. Why? After spending some time doing the right tweaks my printer is printing crazy good. Here are some of my 3D printer tips. Maybe you’re in the market for a printer, use one at school, get access to one through a maker space, or (like me) used to use yours for a desk ornament, these 3D printer tips are likely to help.

5 Common Arduino Programming Mistakes

Wed, 17 Aug 2016 13:39:41 +0000

Whenever someone sends me some code that doesn’t work, there are a few common Arduino programming mistakes that I check. Some of these mistakes I make myself. In most cases my code will compile just fine. Sometimes, these mistakes won’t generate any compiler error. When my Arduino code is acting up, these are the first things I check. Here are my 5 common Arduino programming mistakes, I use to debug non-working code.

3 Way Camera Shoe

Thu, 04 Aug 2016 13:29:19 +0000

When recording videos for either baldengineer.com or, more often, AddOhms, I need at least two things attached to my camera. I used a Canon T5i. The two devices I need to have connected are a shotgun microphone and a wireless receiver. In the past, I just let the remote’s wireless receiver dangle. That really bothered me. I’m still surprised this DSLR shoe adapter didn’t already exist on Thingiverse. Anyway, I created one. Head over to Thingiverse to download it.

Test Equipment Alternatives (Suggested By You!)

Wed, 03 Aug 2016 13:17:55 +0000

A couple of weeks ago, I asked my subscribers for their favorite test equipment alternatives. The reason I asked, was because I recently picked up a Mooshimeter. It is a modern take on the multimeter. However, I will cover that in more detail soon. While I am fortunate that my bench has the usual equipment like an adjustable power supply, oscilloscope, multimeter, and function generator, I know that not everyone else does. I also had to think back to before I had this equipment, what did I use to troubleshoot my circuits.

Adafruit Temperature Sensor Comparison

Wed, 27 Jul 2016 15:00:32 +0000

Getting back to my IoT projects, I decided to pick up a temperature sensor. While looking through the Adafruit breakout boards, I found they offered nine different digital temperature sensors! This list is in addition to the analog TMP36 temperature sensor, so that’s ten. I needed an Adafruit Temperature Sensor comparison. With so many options, I quickly found myself getting lost between the various modules. The 10 I found all measured temperature and provided an I2C interface. Except for the MCP9808 board, they all made at least one other type of measurement. The MCP9808 is the cheapest digital temperature sensor breakout that Adafruit offers, and also the most accurate.

Arduboy Review and Hands-On

Wed, 06 Jul 2016 13:00:37 +0000

When it comes to Kickstarters, I have been relatively lucky. Most of the projects I back have shipped, even if years after I forgot. However, few Kickstarters are something I use on a regular basis. The Arduboy has been a pleasant surprise. This Kickstarter-backed project packages the ease of programming an Arduino into a game playing friendly form factor. Here’s my first Arduboy review, impressions and hands-on experience. Looking back at when I was a kid, there were two gifts I received that made an impact in my life. I have them both to this day: my RadioShack Multimeter and my Nintendo Gameboy. No wonder that my two geek passions have always been electronics and (retro) video games. The Arduboy is a fun little device that combines both! The hardware has the limitations of early 8-bit game machines but the accessibility of an Arduino.

Current Flow Direction

Wed, 22 Jun 2016 13:00:15 +0000

A couple of weeks ago I wrote about four current flow direction myths. As a follow up to that popular post, I decided to dedicate this month’s AddOhms electronics tutorial video to Current Flow. In episode #19, I tackle the question of which way does current flow. You might have heard about “conventional flow” and “electron flow.” In conventional flow, we assume that current flows from the positive voltage towards the negative voltage. In digital, the “negative voltage” is usually called ground. However, that’s not how the electrons move nor is it how they carry the charge around a circuit path.

Watch this video on YouTube

Arduino Bootloader, What is it?

Wed, 15 Jun 2016 13:00:14 +0000

Almost all microcontroller (and microprocessor) development systems use some form of a bootloader. Often called firmware, mistakenly, the Arduino bootloader is one example. Since it is a rather popular platform, let’s use it as an example. Let’s talk about what a bootloader does and how it works. When a microcontroller turns on, it only knows how to do one thing. Typically, that one thing is to run an instruction found at a specific memory location. Often this location address 0x0000, but not always. Usually, this memory location will contain a jump instruction to another place in memory, which is the start of the user program. The bootloader, however, exists in a slightly separate memory space from the user program.

KiCad BOM: Don't Bomb your BOM!

Wed, 08 Jun 2016 13:00:27 +0000

A KiCad BOM is a list of all the parts your design is using. The term BOM, or bill-of-materials, is standard for supply chain management and does not just apply to electronics. KiCad’s eeschema has a BOM export feature. Unfortunately as of Version 4.0, this feature is still somewhat lacking. Given the limitations, here are some tips to take your KiCad BOM from Schematic to Mouser. Spending a few extra minutes while capturing (drawing) your schematic thinking about your KiCad BOM can save you a ton of time later on. Moreover, as you build up a database of parts, these extra minutes turn into seconds. Here are a couple of ways to describe your parts, especially passive components, better while drawing schematics in KiCad.

They're JUST Capacitors?

Wed, 08 Jun 2016 00:20:22 +0000

I was invited to speak at the 11th Hardware Developers Didactic Galactic group at the Supplyframe office in San Francisco. I talked about the misconception that capacitors are a simple device. Chris Gammell recorded the discussion and posted it via PHY Media. This video is about 50 minutes. In this talk, I break down a few things to know about Ceramic, Aluminum, Tantalum, and Supercapacitors. You can see the full video via PHY Media’s YouTube Channel: They’re JUST Capacitors. For links and the slides, check out this post.

Watch this video on YouTube

6 Electronic Safety Tips I learned while Mountain Climbing

Wed, 18 May 2016 13:00:55 +0000

Electronic safety tips from mountain climbing? Yes! After spending two weeks in Europe for work, I had the chance to spend a weekend with friends in Germany. We hiked up Kampenwand in Bavaria. While working my way through the snow and rocks, I realized mountain climbing safety tips were the same as electronic safety tips. Really! Here’s how. Grabbing a soldering iron and throwing polarized components around a circuit board is something I often do. So often, I don’t even realize I’m using some of these electronic safety tips. However, a new activity gives you a chance to exercise the safety portion of your brain. Especially when there are no guard rails.

Four Current Flow Myths Addressed

Wed, 27 Apr 2016 14:00:29 +0000

Current flow (direction) is the topic I’m planning for my next AddOhms tutorial. While preparing the script, I started to realize there are some myths or misunderstandings about electricity and current flow. Ben Franklin Father of Current Flow Everyone probably knows Ben Franklin. He discovered electricity, of course! Yet, he didn’t. Franklin was the first to prove that lightning was composed of electricity with his famous kite experiment. He was also the first to provide electricity’s well-known labels: positive and negative. And somewhere in there Franklin became famous for “inventing” conventional current flow.

Why do engineers (love to) hate Arduino?

Wed, 20 Apr 2016 13:00:02 +0000

A couple of months ago podcast I listen to interviewed an embedded engineer. Eventually, the topic of Arduino came up, and all three people on the show let of sighs of disgust. This lead to me to start thinking about why do engineers hate Arduino? On this particular show, they said Arduino had too many abstraction layers to be useful. All three members of the panel agreed that direct hardware access was critical to success in embedded designs.

Top 25 Websites, Tools and Resources for Hardware Startups

Mon, 18 Apr 2016 13:00:45 +0000

Check out John Teel’s Top 25 Websites, Tools and Resources for Hardware Startups. Hardware startups have the unique challenge of having to spend real money, to physical products, with the end product being something … real. You need all of the help you can get to succeed, which is why John’s list is worth a few minutes. I am familiar with many of the entries but did catch a few new ones. Personally, #9 is my favorite, but I am probably biased.

Switching Voltage Regulator Tutorial

Wed, 13 Apr 2016 13:00:04 +0000

A switching voltage regulator is one of my favorite circuits. In school, they were the first circuits I built where I understood how transistors worked. In fact, they were the first circuit I saw an inductor being useful! Switching regulators are incredibly efficient when designed properly. Of course, this detail about design is important. They are not as simple as a linear regulator, which is basically an IC and two caps.

Hands-on with Arduino Create and Arduino IoT

Wed, 06 Apr 2016 13:00:00 +0000

This past weekend Arduino fans celebrated Arduino and Genuino Day 2016. In classrooms, maker spaces, and impromptu meet-ups around the world enginerds got together to learn and create with Arduino. At the Jacobs Institute for Design Innovation on Berkeley’s Campus, I first heard that Arduino Create had been launched. In addition to hands-on learning workshops, there was a display of Arduino/Genuino projects by students. In the afternoon, three Arduino co-founders gave a short talk. David Mellis spoke on Machine Learning. Tom Igoe did his first talk on Technology and Humanities. Lastly, Massimo Banzi talked about IoT.

How to Turn Your Arduino Prototype Into a Manufacturable Product

Wed, 30 Mar 2016 14:00:33 +0000

This week’s post is from my friend John Teel. I asked him to help answer a common question I receive: " How do you make an Arduino project into a product?" His experience as an electronics design engineer and serial entrepreneur is ideal to talk about going from prototype to product. He has developed tech products that sell in the millions of units. John now helps entrepreneurs, startups, makers, and small companies bring new electronic products to market. Check out the company he founded, Predictable Designs, and his free cheat sheet - 18 Steps to Market for Your New Electronic Product after reading his excellent post below. Dreaming of bringing a new hardware product to market? Perhaps you think your product will make the world a better place, or maybe you just dream of making millions of dollars.

Energy Density of 9V battery vs. AA batteries

Wed, 23 Mar 2016 13:00:53 +0000

Previously I wrote up why the 9V battery sucks. As I thought more about that post, I realized, I never explained how much energy is in a 9 V battery versus say a couple of AA batteries. For this post, I am going to break down the energy stored in a 9 V battery, the small rectangular kind and compare it to what you get with 6 AA batteries. Yes, it takes up a little more space, but you might be surprised by the difference.

Chuck Norris On Pull-Up Resistors

Fri, 11 Mar 2016 06:51:18 +0000

Think you can do without Pull-Up Resistors? Only Chuck Norris doesn’t need them.

Logic Analyzer Tutorial and Introduction

Wed, 09 Mar 2016 16:00:17 +0000

A DMM, or multimeter, is the go-to instrument for debugging most circuits. You probably already have at least one DMM on your bench for this reason. Me? I have three. But that’s a different story. Let’s talk about a Logic Analyzer. Digital signals represent two states: on (usually “1”) and off (usually “0”). A multimeter (DMM) may be of limited value for these signals. When using the DC voltage measurement, you can see “something” is happening, but not exactly what that “something” is. For example on a PWM pin, you’ll see the RMS Voltage change as you modify the duty cycle. However, you can not see if the signal is “ringing” when turning on and off.

Arduino to ESP8266, 5 reasons to switch

Wed, 02 Mar 2016 16:00:04 +0000

A couple of weeks ago I posted four things to know about the ESP8266 before using one. The biggest surprise from that post is people seem to think I do not like the ESP8266! This idea is not the case; the ESP8266 is awesome. I like them so much that my Adafruit Feather HUZZAH with ESP8266 has become my go-to Arduino board. Wait what? James uses something other than Arduino? Yes, I do! I have many different boards and have used most of them for one task or another.

MQTT Tutorial for Raspberry Pi, Arduino, and ESP8266

Wed, 24 Feb 2016 16:00:45 +0000

This week’s MQTT Tutorial connects a Raspberry Pi, ESP8266 (or Arduino), and a PC together. Remember last week’s post provided an overview of message brokers and MQTT. We learned that MQTT is a hub and spoke protocol for sending messages between IoT devices. Clients can subscribe or publish messages to a central server, called a broker. Now it’s time to connect our IoT devices together! For this MQTT tutorial, I have three main elements: • My Computer, which will act as the broker. • Raspberry Pi running Python • ESP8266 controlling an LED

MQTT Introduction and Tutorial Part One

Wed, 17 Feb 2016 16:00:25 +0000

MQTT is an easy way for Internet of Things (IoT) devices to communicate with each other. This light-weight protocol can be used with a simple 8-bit Arduino to a Raspberry Pi to a multi-core PC to Amazon Web Services. It is that versatile. This MQTT Tutorial is broken into two parts. Part one is an MQTT Introduction. You’ll understand how publish/subscribe message brokering works. Next week, Part two will be a tutorial on using MQTT to communicate between a PC, Raspberry Pi, and ESP8266.

Raspberry Pi GUI Tutorial

Wed, 03 Feb 2016 17:58:53 +0000

My favorite Raspberry Pi add-on is the PiTFT from Adafruit. With it, you easily get a Raspberry Pi GUI interface and touch screen. The PiTFT software install is just a few things and it is good to go. Adafruit PiTFT - Click for more info This screen is what I needed for my IoT project. The Pi+Screen will act as the primary controller for all of my things. The problem is I didn’t know much about writing GUI applications in Linux. So what could I do to create a Raspberry Pi GUI?

Full Size LEGO BB-8 time lapse build by Bright Bricks

Tue, 02 Feb 2016 19:00:23 +0000

Quick timelapse video of Bright Bricks building a life-size BB-8 unit. Surprising to me was that I always imagined these builds solid with LEGO pieces. Turns out, they are built an internal structure, which makes more sense really. Either way, watching this short LEGO BB-8 build is fun.

Watch this video on YouTube

Use Arduino millis() with buttons to delay events

Wed, 27 Jan 2016 16:00:16 +0000

One of the common questions related to using the millis() function in Arduino, is around timed events. After an event occurs, you want the code to wait for some time before doing the next step. But you don’t want to stop the program with delay(). In this example, we will use millis() to wait a few seconds after a pushbutton press to turn on an LED. Then a few seconds later, we will turn it off. All without using delay().

Bald Engineer's Top 2015 Stuff

Wed, 30 Dec 2015 16:00:33 +0000

As 2015 wraps up, I took a look at baldengineer.com’s traffic for the past year. Here’s some of the most popular stuff from my blog, in case you missed it. Everyone with a blog looks at their traffic numbers. For me, traffic data provides feedback on what tutorials or posts are helping people most. Each year, the traffic to my blog grows at ridiculous numbers. As someone with both an engineering and marketing background, I find the numbers impossible to believe.

Four ESP8266 Gotchas and a tip for a first time users

Wed, 02 Dec 2015 16:00:13 +0000

Adding WiFi to any project can be difficult. There are a few off the shelf options that make it easier. One option is the official Arduino WiFi shield. This full-featured shield uses its integrated microcontroller to handle the WiFi protocol, security, and the TCP/IP stack for you. From “plug it in and go” perspective, this is an awesome option for Arduino-based projects. Plenty of example code supports the nicely designed hardware. The main downside to some people is the price.

2015 Holiday Gift Guide

Wed, 25 Nov 2015 16:00:49 +0000

This week marks the start of the 2015 Holiday Shopping Season. Being a short week for me, I thought I’d offer up some gift suggestions for engineers. Being the only engineer in my immediate family, gift giving time is always interesting. Many times I wished I could give them a list of unusual items, without saying “here buy these.” Whether you want to gift something to a fellow electronics enginerd or you to offer your family some suggestions, there is something on this list.

Difference between Programming and Native Ports

Wed, 11 Nov 2015 16:00:04 +0000

When you hear the name “Arduino,” does a picture of the Uno come to mind? While the most popular, this 8-bit based board isn’t the only Arduino available today. There are some other boards available like the Due and recently introduced Zero, which are far more advanced than the humble Uno. These are 32-bit microcontroller boards that have a very different architecture compared to the relatively straightforward Uno. In fact, one of the most striking differences is that the Due and Zero have two USB ports.

Build a proper R-2R DAC

Fri, 06 Nov 2015 16:10:58 +0000

Creating real analog outputs from a digital pin is possible when you use an R-2R DAC. What is a DAC? The letters stand for D igital to A nalog C onverter. This simple DAC is built using resistor. The principle works on voltage dividers. By enabling different combinations of resistors, it is possible to get various voltage levels. Obviously, such a simple design will have some trade-offs.

FleaFPGA Introduction

Wed, 04 Nov 2015 17:00:09 +0000

Can’t find the digital chip you need on Mouser or just wish you could make it yourself? With the FleaFPGA board, you can! As a college freshman, we heard rumors of a custom Integrated Circuit (IC) class. Surely what had to be a senior level class, I couldn’t wait until I understood electrical engineering enough that I got to make my own IC! Two years passed, I was learning Verilog and VHDL in a class titled “Complex Programmable Logic Devices.” In short, CPLD. Those devices were the precursors to today’s modern FPGA devices.

A Whole New Engineer

Mon, 02 Nov 2015 18:38:30 +0000

A couple of weeks ago I was invited to join The Engineering Commons podcast to talk about capacitors on episode 93. I had been a listener of the podcast because I heard about it in this book. A Whole New Engineer looks at the changes are needed in engineering education. My personal interest was to see if there were elements I could apply to the AddOhms Electronics Tutorials I create. Like all aspects of our lives, evoluation is occuring and educaiton is no different. On top of that, traditional education techniques rarely prepare students for live after school.

EngineerDog explains why stressed plastic turns white

Thu, 01 Oct 2015 13:00:51 +0000

Polymer Crazing via engineerdog.com Ever notice when you over-stress plastic, the stress points tend to turn white? The color or type of plastic doesn’t seem to matter, does it? So what is going on? This awesome post from EngineerDog explains why stressed plastic turns white. If you’re starting to work with ABS on your 3d printer, it will help to understand what is happening to the polymer chains. It’s a process called crazing.

My Modular Soldering Station for the Space Limited

Wed, 30 Sep 2015 13:00:06 +0000

Solder is the glue of electronic circuits. In addition to a permanent mechanical connection, solder provides an electrical connection. Not too much unlike glue solder combines two separate metal pieces with a bonding material. In this case, the bonding material is a metal or allow with a relatively low melting point. When soldering together a circuit, the quality of the solder joint is crucial. Most people probably recognize the need for a high-quality soldering iron, like the FX-888D from Hakko, but about the other tools?

Corner Case: 90-deg turns for WS2812

Tue, 29 Sep 2015 13:00:34 +0000

NeoCorner from josh.com If you’re working with the WS2812B and need to turn corners, you’ll want to check out this NeoPixel Corner adapter PCB from josh.com. It’s a pretty simple board. I came across it as a solution for an upcoming lighting project. In josh’s example, he used a CNC to mill the PCBs. If you’re using one-sided FR4, that might work well. You’ll want to double-check thicknesses if you want to use OSHPark or similar.

Makers keep your eyes out for these 8 "Trash" Types

Mon, 28 Sep 2015 13:00:48 +0000

Dumpster diving can be a rewarding experience for a maker. You never know what components you might be able to recover from electronics otherwise discarded. What can be hidden inside of an “obsolete” box? Motors? Sensors? Capacitors? Older technologies like VCRs and Scanners can be a treasure trove of stepper and servo motors. Under-powered, by today’s standards, computers probably have cables that can be re-purposed into your current project.

Benchmarking Arduino's digitalWrite() with a Logic Analyzer

Wed, 22 Jul 2015 13:00:55 +0000

Recently I picked up a device called Logic from Saleae. It’s a 4-channel USB-based logic analyzer. While learning how the simple, but effective, UI works I ran some timing benchmarks on my Arduino Uno. The subject? digitalWrite(). I wanted to know how fastdigitalWrite() could turn on two (or more) pins. Almost all Arduino users start out with the simple “blink” sketch. Turn pin 13 ON, delay, turn it OFF, and delay again. The heart of this version of “Hello World!” is the digitalWrite() function. Many Arduino users never even think about all of the stuff this single function call hides.

Flag variables are not evil (for Microcontrollers)

Wed, 15 Jul 2015 13:00:13 +0000

Getting programming questions answered on the internet can be problematic. Programmers love to have opinions, stick to those ideas, and express them to you even when their opinion has nothing to do with your question(s). Not only am I going to explain how to use flag variables in your code, I am going to encourage their use—which most programmers avoid. However, this advice comes with two caveats. This information only applies to limited resource environments like an Arduino, LaunchPad or PIC. Use flag variables very carefully when you do use them. The following flag variable usage examples are Arduino-centric but apply to any microcontroller platform, including the Energia project for TI Launchpads.> Flag variables are a Good Thing(tm) – when used properly

Which Arduino Starter Kit is the Best?

Wed, 01 Jul 2015 13:00:33 +0000

The other day my friend called me up. He told me how much he missed building circuits and wanted to start again with the Arduino. So he asked me “which Arduino starter kit is the best to buy?” At which point, I drew a long breath. Easy question, not always an easy answer. Picking out an electronics kit depends on a number of factors. You should consider: Your budget What you already have What you want to do #1 and #2 are probably pretty easy to figure out. For many beginners, it’s “not much” and “nothing.” When you don’t know #3, what you want to do, then it gets trickier. Coming back to my friend, what did I do? Well, I went out and bought each one of the kits in this post. I put myself in his shoes and maybe these are your shoes as well.

How to find parts for your electronics projects and designs

Wed, 24 Jun 2015 13:00:58 +0000

What part is the most important part in building a project? All of them! Okay, bad joke. Selecting the right parts or components for a design is an area where both new hobbyist and veteran engineers struggle. The wide variety of devices make it almost impossible to know if you are selecting the right one. Looking at a curated List, using component search engines and browsing DIY shops are how I tend to find parts for my projects.

X-Carve CNC Review and Hands-On with PCB Milling

Wed, 10 Jun 2015 14:00:07 +0000

There are two methods to making a prototype PCB: 1) Etch Your Own or 2) Send to a Prototyping Service. While there are many prototyping service options, most cause you to wait anywhere between 24 hours and 30 days before you get your boards back. If you need a PCB done today, etching at home is a great option. Chemical etching involves all kinds of steps with all kinds of weird chemicals. If you don’t want your neighbors to think you’re the next Walter White, then mechanical etching is a better option. Which is why I bought an X-Carve from Inventables. It’s a CNC Milling Kit you build yourself.

How do you remove Jitter from a signal?

Fri, 05 Jun 2015 14:00:00 +0000

Use de-caffeinated Silicon, of course!

Get electronics help with the right question

Wed, 03 Jun 2015 14:00:03 +0000

4 keys to getting electronics help for your project When describing a person, do you ever use the phrase “their strength is their weakness?” That’s how I feel about Internet forums. The strength of forums is the collective knowledge of like-minded people, some with more experience than others. Sadly, that is also the weakness of Internet forums… Whether it is a topic-specific site like the EEVBlog Forum or an almost anything site like Reddit the strength/weakness holds true.

Add wireless with one of these five wireless modules

Wed, 20 May 2015 14:00:07 +0000

Your IoT project needs one of these wireless modules Getting your project connected to the internet is relatively easy these days. Here are five off the shelf modules that will easily add wireless to your project. Back when I was in school, I remember spending an entire semester making a RF amplifier board. In fact, I had to use a pencil eraser to remove oxidation on the copper traces to remove an unwanted oscillation, caused by the impedance mismatch of the oxidation on the copper traces. Talk about tough.

An Open Letter to Arduino LLC and Arduino SRL #OneArduino

Fri, 10 Apr 2015 13:00:31 +0000

Most of the major electronic blogs have covered the controversy between Arduino LLC and Arduino SRL. My first deep look into it was from Hackaday’s Arduino v. Arduino. Since it has been covered so well by others, I won’t re-hash the already known facts. If you want to join in giving feedback to these companies, please tag your posts, tweets, and content with " #OneArduino".

Watch this video on YouTube

Don't be afraid of learning a new tool

Wed, 08 Apr 2015 14:07:13 +0000

Behind-The-Scenes of AddOhms #14 After moving from learning a new tool to mastery, the resistance for me to switch becomes very high. This can apply to hardware tools like a drill, saw or CNC milling machine. It can also apply to software tools like EAGLE, Programming Languages or video editing software. In AddOhms #14, I gave an overview of the VirtualBench from National Instruments which I’ve covered on this blog as a hands-on, written review and video review.

Come See The Baldengineer's Presentation at APEC 2015

Wed, 11 Mar 2015 14:01:44 +0000

Supercapacitors in Transportation Applications at APEC 2015 The Applied Power Electronics Conference 2015 (APEC 2015) celebrates its 25th year in Charlotte, NC. The conference opens on March 15, 2015 and is focused on power electronics. The schedule of technical sessions range from industry experts to students presenting research papers. APEC’s exhibit floor is usually packed with every vendor in the power electronics supply chain. This is one of the largest electrical engineering shows in North America—and I’m excited to announce I will be presenting in one of the industry sessions!

PCB Checklist - What to check before you submit

Wed, 04 Mar 2015 15:22:50 +0000

Recently I’ve been expanding my retro game collection to include game cartridges imported from Japan. The problem is that I don’t have Japanese game systems (yet). So I’m creating an open source adapter to convert Famicom carts to the NES. Before I submit the PCB to OSH Park, I’m going to run through this PCB Checklist to make sure I don’t forget something silly. This PCB checklist is something I’ve built over my years of creating boards. If you’ve got tips from your own list, don’t forget to leave a comment letting us know.

Captain Picard on Decoupling Caps

Mon, 19 Jan 2015 14:56:25 +0000

Fun with the meme generating. When it comes to adding decoupling caps, Make It So.

[TIP] Fixing Garbage Serial / UART Communication

Tue, 06 Jan 2015 15:02:43 +0000

If you’re using serial (or UART) communication between two devices and seeing data corruption, there could be a simple fix. For example you might be trying to communicate between two Arduino boards, using one Arduino Uno as a Serial-to-USB adapter for another board, or have an Arduino connected to a Raspberry PI. If you’re getting corrupted transmissions that get worse at lower speeds, double-check you have common grounds between the boards. Inductive coupling is probably letting the communication work. Without the common ground though, your transmission is going to be susceptible to all kinds of noise.

My Top 10 Posts from 2014

Wed, 31 Dec 2014 14:07:30 +0000

From Jan 1 2014 until today, baldengineer.com’s traffic has increased 150%. With so many new readers, I thought about how to make better posts for you. That lead me to look at the top posts in 2014. Below are the most viewed posts from the past year, plus some honorable mentions. 5 Myths Everyone Believes about Arduino (that aren’t true) millis() Tutorial: Arduino Multitasking Arduino: How do you reset millis() ? MSGEQ7 Simple Spectrum Analyzer When do you use the Arduino’s Serial.flush()? Arduino: Sending and Receiving Multi-Digit Integers Arduino Internal Pull-Up LED Basics Open Vapors – Open Source Toaster Reflow Oven – Overview Alternatives to Arduino’s Serial Monitor Learnings You know what is interesting? There is only one post for 2014 and it’s #1 on the list. Guess that one resonated with some people. Also, except for #8, the top posts all relate to Arduino in some way.

How does a transistor work by Veritasium

Fri, 26 Dec 2014 16:05:17 +0000

One of the best ways to describe a transistor is as an “electronic switch.” They are solid state devices that make up almost everything in our world. This video by Veritasium, which is a bit older, covers how n and p-type transistors actually work. This complements the Addohms videos on BJTs and MOSFETs, which are more about how to use them.

Watch this video on YouTube

Happy Holidays and Merry Christmas

Thu, 25 Dec 2014 11:00:19 +0000

Minecraft animation from PoetPlays. Happy Holidays Everyone.

Watch this video on YouTube

Software Defined Radios are Awesome

Wed, 10 Sep 2014 12:00:27 +0000

Early in my engineering career, I worked for an oscilloscope company in the high performance product line. The last project I worked on was defining the features and requirements of a 33GHz (that’s giga-, not mega-) scope. This experience gave me a strong appreciation for processing digitized signals, especially those in the RF range. So when I picked up my first Software Defined Radio (SDR), you can imagine how much fun it was to use… with the help of some open source hardware.

Please take my 2014 Reader Survey

Mon, 23 Jun 2014 15:00:49 +0000

I want to make my blog a better for your interests. That means, I need to know about YOU! Would you please take a few minutes and answer a few questions? By doing so, you’ll actually be helping yourself. How? Because I’ll be able to make better content and more posts that are relevant to you. Survey link: https://www.surveymonkey.com/s/VLHQSZJ To keep all of the responses anonymous, I am using SurveyMonkey. The reader survey is only 2 pages and 10 questions, so it should takes you less than 5 minutes.

Are you an engineer?

Wed, 11 Jun 2014 20:48:26 +0000

One of the recent changes in pop-culture is that “nerds are cool.” Most people who claim to be a nerd like to wear 1950s (non-corrective) glasses and download Apps on their iPhone. Some go farther and say they’re engineers. Here’s how you can sort out the posers. The original author for this test is unknown. A quick Google search comes up with a number of duplicates, but no one claiming to be the author. So, republished with my own comments (and slight edits) is, the “Engineer Identification Test.”

The 4 best transistors to keep in your parts kit

Mon, 21 Apr 2014 15:00:38 +0000

When your project needs a transistor, there are tons of choices. Which makes answering the question “Which transistor should I use or buy?” a daunting task. Fear not, before wading through spec sheet after spec sheet, consider one of these four general purpose transistors. Every electronics enginerd’s toolbox should have a few of each. Transistors are one of the most versatile discrete components in electronics. In digital circuits, they switch on and off while in analog circuits they are used to amplify signals. For most projects, they are used to turn on a load that would kill the I/O pin of a microcontroller or microprocessor. For most circuits either a BJT or MOSFET can be used, depending on the load current you need to switch.

Teach your Arduino to listen with µSpeech

Tue, 08 Apr 2014 15:00:11 +0000

When most people say “Arduino” they mean an ATmega328 based board like the Uno. This means a simple 8-bit microcontroller with only 2K of RAM. That’s 2,048 bytes of memory to work with. So when someone asked me if the Arduino could do speech recognition, to be honest, I laughed. Then my jaw dropped when I saw µSpeech. A speech recognition library for the Arduino Uno’s ATmega328. The algorithm used is sophisticated and results will vary based on the types of words used as well as the hardware. It uses only 160 bytes of RAM.

April Fools' 2014 Jokes for Enginerds

Tue, 01 Apr 2014 16:35:12 +0000

Each year it is fun to see who gets “got”. With Twitter fever getter hotter each day, people can’t help but spread juicy news details. Here’s a running list of the April Fool’s Gags I ran across in 2014 (updated links at top of list) OSHPark is going to switch to Green PCBs https://twitter.com/oshpark/status/451084822317113344 Instructables going to sell all their Instrustables in a single book http://www.instructables.com/community/Coming-Soon-EVERY-Instructable-one-massive-book/ Waze Introduces WazeDates (Video) https://www.youtube.com/watch?v=XfCS9CN91RU Make Magazine’s list of reader’s pranks http://makezine.com/2014/04/01/prank-call-and-answer/ Sphero Introduces “Selfibot” (Video) https://www.youtube.com/watch?v=ZaR4X2iJo6M Raspberry Pi Shows off new retro design Click here for a Cached Screenshot of the Pi Joke Page Kickstarter is changing it’s name (less vowels) https://www.kickstarter.com/blog/the-new-kickstartr Single Person Tool Shop, Boldport, Acquired by Apple http://boldport.blogspot.com/2014/04/apple-acquires-boldport.html Octopart Now supporting Snapchat http://octopart.com/blog/archives/2014/4/now-send-rfqs-using-snapchat%2521 iFixIt Acquired by Apple http://www.ifixit.com/apple_press_release Complete with red herring as shown in their new Smartphone Replaceability Indexes Think Geek’s Flux Capacitor Charger Seriously hope this one becomes real: http://www.thinkgeek.com/product/1ba1/ Sparkfun ran a sporting contest https://www.sparkfun.com/news/1443 Bored Elon Musk’s Tweet on if you should do an April Fool’s Joke https://twitter.com/BoredElonMusk/status/450765914875518976 I can’t help but think that Apple is going to not like repeatedly being used in these yearly jokes. What jokes have I missed or what were your favorites? Leave them in the comments.

AddOhms: Questions and Answers #1

Fri, 14 Mar 2014 02:00:31 +0000

In the past couple of months, AddOhms has caught a little bit of a following. Nearly every day I have new questions coming my way. I decided to it was time to address a couple of really good questions in a video response. Ironically, in the video I mentioned giving “behind the scenes” info with each video. However, for this one, I don’t really have any. I can say that the next video is going to be on transistors…

9V Batteries Suck -- And why you shouldn't use them.

Fri, 14 Feb 2014 12:00:37 +0000

Smoke detectors beep when their backup battery dies, which always seems to occur in the middle of the night (at least for me.) These backup batteries are usually a small rectangular 9V. They have become popular choices for electronics projects. If you need your Arduino project to last longer than a day, this isn’t the battery you want to use. Here’s why. What is a 9V Battery The 9v battery comes in a standard package about 25mm wide, 16mm tall, and 47mm long. On top there are standard snap-style connectors. The design of these connectors prevents you from attaching the battery backwards.

3 Options for Keeping Track of your Parts

Wed, 12 Feb 2014 12:00:45 +0000

As your electronics hobby grows, so does your parts collection. Eventually the growing number of Mouser boxes with crudely written labels just won’t cut it. Also, you’re tired of re-ordering parts you had but forgot about. Here’s a couple of ways to keep track of your parts like a pro. Text File (aka Evernote) The most basic option is a text list stored as a text file or in your favorite note taking app. Eventually I moved my text file over to Evernote. It had the benefit of being mobile so I could update it as I found those parts hiding in plain site. The limitation though is that it’s just a flat text file. No sorting, limited searching, and nothing to prevent duplicate entries.

A week of Arduino Millis()

Mon, 09 Dec 2013 13:25:24 +0000

By far one of the most powerful functions of the Arduino library is the millis() counter. It is also one of the most misunderstood functions. Mastering millis() can unlock incredible amounts of potential with an Arduino. That’s why I’m spending an entire week on millis(). Each day this week I’m posting a new example of how to use millis() in your code. Each will be cataloged on this newly created Arduino Millis() Cookbook Page. If you have ideas for other examples, leave comments below.

AddOhms #6: Analog and Digital

Wed, 13 Nov 2013 12:52:09 +0000

It isn’t always clear what is meant by calling a device or a signal “analog” and “digital”. This AddOhms tutorial explains the difference between analog and digital by using an analogy to clocks. Old-school clocks with hands are a great example of “analog” while alarm clocks with digits as their display are an excellent example of “digital”.

Understand the difference between DC and AC

Wed, 25 Sep 2013 14:10:17 +0000

The fifth episode of AddOhms tackled the difference between AC and DC. One of the things I wanted to stress in this tutorial is that even though the acronyms stand for “current”, they get used to describe voltages as well. Which, after a video on the difference between voltage and current, seemed like something that needed to be stated.

Ouch. The Arduino GSM shield has a pretty serious design flaw, with its capacitors.

Sat, 14 Sep 2013 02:44:39 +0000

Tantalum is a really misunderstood capacitor. Well, all capacitors are misunderstood, but that’s a subject for another post. I ran across this post on the Arduino forums on the Arduino GSM shield. In the post, ddewaele, reports that the shield blew up, catching fire. At first some might think it was due to abuse by the user. While it is possible that reversing the polarity or applying over-voltage could cause a catastrophic failure, it is also possible that the user doing nothing wrong could result in the same failure mode!

A new series on AddOhms, Electronics basics, starting with: Voltage, Current, and Power Explained.

Sat, 13 Jul 2013 00:53:31 +0000

Starting with this new AddOhms TutorialCast series, we are taking a look at Electronics Basics. The first topic is on the differences between Voltage, Current, and Power. The twist on this explanation is that we are not using the usual “electricity is like water” analogy engineers seem to love. Instead, we just use plain language to explain the difference between these concepts. From a production point of view, I am really having fun with these videos. Using some green card stock, imagination, and easy to use tools, I am able to achieve some pretty cool effects. Well, I think they are pretty cool. Check out this screen shot from Final Cut Pro X.

Introducing the AddOhms TutorialCast

Sun, 05 May 2013 20:53:51 +0000

Over the past several months I have been kicking around a new way to teach non-engineers about electronics. My idea is to use simple language to explain complex engineering subjects. Each video will be in the range of 3-5 minutes. While putting together the first couple of topics I started to realize I wanted this to be something to stand on its own. So I have created a separate webpage, twitter account, and YouTube Channel for this TutorialCast called “AddOhms.”

Prototyping quadrotor arm mounts with MakerBot Replicator 2

Sat, 27 Apr 2013 22:45:27 +0000

While practicing the Quadrotor’s motor mounts on a Shopbot gave me experience in how to register two sides for milling, I didn’t want to invest the time required for the arm mounts. So I decided to make use of the MakerBot Replicator 2 to print physical samples in PLA. Time per piece went from about an hour to about 15 minutes. This is the first time I used the Makerware software, which looks to be a much prettier version of ReplicatorG. The workflow for using the software is a little bit more straight forward than ReplicatorG. For example, a single “Make” button generates the Gcode and Scd Files

The world's thinnest watch, the CST-01

Wed, 09 Jan 2013 02:23:15 +0000

Update 03/24/2015: I (finally) got mine after a couple of years. In fact, I completely forgot about it. The watch is crap. I threw it away before ever wearing it out of the house. There’s a Kickstarter project that Andrew Plumb (@clothbot) backed and caught my attention. It is a wrist-band watched based on an e-ink display. The battery cell looks like it can provide about a month worth of charge. A very unique looking watch and for an (apparently) limited time, there is a $100 reward level. As Andrew said, it might be worth it to just take the watch apart!

Laser Cutting Christmas

Tue, 01 Jan 2013 00:34:22 +0000

For Christmas this year, I decided to do something different for my immediate family. Instead of trading gift cards like we usually do, I decided to put to use the Laser Cutter at my Local TechShop. When done, I decided to use iMovie on my iPhone to make a mini trailer…

Making a 3D print with the MakerBot Replicator

Sat, 24 Nov 2012 00:21:33 +0000

Recently TechShop opened up one of their shops in Round Rock which is just a few minutes from Austin, where I live. TechShop is an awesome membership based workshop with a huge variety of tools useful for making things. On this holiday Friday I decided to spend some time with the MakerBot Replicator. For some time I have been looking at a mini-tripod for my camera/iPhone so I could get pictures of projects while working on them. While browsing Thingiverse, I came across design files for such a thing.

First impressions of the Arduino Due

Fri, 23 Nov 2012 04:49:45 +0000

I’ve been working with Arduino boards for a number of years, as shown by the dates on some of my older blog posts. In that time I’ve only used boards based on the ATmega8 (like the Duemilanove or Uno). The Due is the first Arduino board I have used in what I would call the Mega form factor. Physical Differences I’m surprised by the size difference. I’ve always thought the original Arduino form factor was small, the Due is larger but still feels small.

Long Overdue LaunchPad Review

Sun, 30 Sep 2012 14:13:26 +0000

Recently I realized most of my projects were all Arduino-based. There are lots of other prototyping platforms available in the market, and the TI LaunchPad, based on the MSP430 is one of them. In fact, I have had one of these boards sitting in my box of stuff ever since they came out. At $5, they because an impulse purchase when I was buying some other stuff.

Raspberry coming to a Hackerspace near you

Mon, 20 Aug 2012 09:58:51 +0000

One of the Raspberry Pi Foundation’s developers, Rob Bishop, is heading out on a Hackerspace tour in the US. Looks like he’ll be visiting a couple of spaces on the west coast, east coast, and my home town: Austin, TX. [Via raspberrypi.org Raspberry Pi Foundation US Hackspace Tour | Raspberry Pi]

Renesas Promotion Board for RL78/G13 | Renesas Electronics America

Wed, 15 Aug 2012 10:42:23 +0000

Renesas is offering a promotion version of their RL78 microcontroller. This offer is only available to their Sample Component account holders, but the process for signing up for a sample account is pretty straightforward. (There may be EAR restrictions with this board.) If you are looking for a powerful processor that is an alternative to PIC or AVR processors, this board might be worth a look. Note: It appears samplecomponents.com might have been compromised at some point in the past. Google throws a warning page up. Proceed at your own discretion.

OSX: Cathode, Best Terminal Ever!

Thu, 19 Jul 2012 13:26:26 +0000

Cathode from Secret Geometry is, hands down, my favorite Terminal Emulator for OSX. It is, in my opinion, (near?) perfect emulation of classic computer terminals from the 1980s. When using it, it reminds me of how far computers really have come. It is also one of the funnest ways to ssh into a remote host to edit a CSS file real quick. I like keeping mine set to 14.4k baud emulation. The screen blur, when running Full Screen in Lion, almost makes me forget I’m using an LCD!

Why You Suck At Changing The World; Try Hardware - Upverter

Tue, 14 Feb 2012 02:05:28 +0000

T he iconic picture of a homemade case for the Apple I, the computer that changed the world, is a great image for Upverter’s post about… changing the world. While most of today’s attention grabbing innovation comes from clever software apps, most forget that the hardware the apps run on require significant investments in engineering time. Making the next “multi core processor” is not a simple copy and paste function. Nor are there any “Getting started with complex digital design books” you can breeze through in a weekend.

The next step in wearable fabrics: fabric batteries

Wed, 08 Feb 2012 02:22:38 +0000

Researchers at the Polytechnic School of Montreal have figured out a way to turn a battery into a flexible material. Each strand of the “battery” is 0.6V. While exciting, it has one major drawback before commercialization: it isn’t waterproof yet. How to: Weave a flexible battery into fabric material - Electronic Products.

Spotting Arduino Clones

Mon, 26 Dec 2011 23:40:20 +0000

Open Source Hardware (OSH) means not only releasing devices, but all of the documentation associated with them. For some projects, this may include the actual CAD files used to produce the device. For example, the Arduino team produces not only schematics but the Eagle PCB CAD files for each of their boards. The great thing about such disclosure is that one can easily tweak the existing design for their own purposes. The downside is that nearly anyone can submit the exact same files to their own production house and have immediate clones.

Arduino UNO SMD Amnesia

Thu, 20 Jan 2011 16:10:22 +0000

On the Janurary 15, 2011 edition of Adafruit’s “Ask An Engineer” live video chat, I heard LadyAda mention something about “Arduino Amnesia.” After investing the situation a little further, it turns out there are some Issues with the new Arduino UNO Smd edition. A bug in the new bootloader can be triggered on power-cycle causing the SMD version of the board to not load the previously stored sketch. The good news is there is already a fix for the bug. Either return the board to your Official Distributor or use a ISP to program the new bootloader.

Why are you spamming me?

Wed, 10 Jan 2007 03:01:56 +0000

Nobody at “cmiyc.com” or “cmiyc.org” will send you email. In fact, I don’t even have an outgoing mail server setup. So if you receive emails from me, a spammer is forging my domain name in the email headers. There is little that can prevent this, since it is something that happens in between you and I. All I can say, it is perfectly safe to drop any emails that appear to come from “cmiyc.com”.