AddOhms on Bald Engineer

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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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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Learn Oscilloscope Basics with an Arduino Uno

Mon, 03 Sep 2018 14:10:11 +0000

Learning to use a new oscilloscope can be daunting. In this video, I show 5 measurements you can make using just an Arduino as your DUT. Learn how to offset voltage, setup measurements, enable infinite persistence, save reference waveforms, AND trigger (and decode) serial signals. For this video, Rohde & Schwarz was kind enough to send me an RTM3004. This video is a follow-up from an ealier blog post which featured 6 scope measurements you can make with an Arduino.

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MKR 4000 VIDOR Hands-On Video | AddOhms Live

Tue, 14 Aug 2018 13:47:52 +0000

As promised, the Arduino team shipped the MKR 4000 VIDOR by the end of July. The graphical editor is still missing in action, but you can check out the board now. I received mine. In this AddOhms Live Stream, I turned it on and checked it out. This video is a “working” live stream. Generally, I try to set up some demos and run through some canned actions. Not this time. I used the board once, on another computer. You get to watch how I attack a new board…live! Warts and all.

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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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Programming Adafruit Coin Acceptor on AddOhms Live

Mon, 18 Jun 2018 06:00:26 +0000

This week the bald engineer unboxes swag from electromaker.io, programs the Adafruit Coin Accepter, with a Pyramiduino, and answers questions along the way. Interesting time code jump points: 7:59 - See Programming Bootloader Clip 12:11 - Coin Acceptor Programming 18:00 - Pulses on the R&S RTM3004 Oscilloscope 42:05 - Code working as intended!

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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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Picking Pull-Up Resistor Value | AO #25

Fri, 04 May 2018 21:14:16 +0000

Common question that comes up about pull-up resistors: what value do you pick and why not just use a piece of wire? In this follow-up electronics tutorial, the bald engineer looks at how to pick a pull-up resistor value. Note that while focused on pull-up everything said in this video would apply to pull-down as well. If you’re new to pull-up resistors, check out this longer Pull-Up Resistor Tutorial. Watch the full video

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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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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.

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.

Crazy Circuits Hands-On and Q&A (AddOhms Live!)

Mon, 18 Dec 2017 14:43:39 +0000

In April 2017 I backed a project on Kickstarter called “Crazy Circuits.” It looked like a cool concept that was well developed, so I even included it in the Baldengineer Newsletter. I do not typically promote Kickstarter projects–unless they are exceptional in some way. I liked the concept of circuits that worked with existing LEGO-sized boards and pieces. Their shipping was a couple of months off, but nothing compared to some Kickstarter disasters. I received my Crazy Circuits kit in November, compared to the promised September.

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Voltage Dividers as Regulators?! | AddOhms #22

Mon, 16 Oct 2017 13:00:15 +0000

Can you use voltage dividers as regulators? What if you add a Zener Diode? In this AddOhms episode, I show what happens when you try to power a complex circuit like an ESP8266 with a voltage divider instead of a regulator. (Spoiler: Get a voltage regulator.) This video tutorial is related to a write up I did recently on Zener Diodes. For questions or comments visit the AddOhms Discussion Forum. Behind the scenes A significant change for this AddOhms Episode is that I moved from Final Cut Pro X to Premiere Pro. I also shot the entire video in 4K, even though the output is 1080p. Animations were still done as 1080p compositions. One snag I ran into, the color corrections I applied in PPro, didn’t seem to get exported. You might notice when the breadboard is on screen, it has a very slight yellow tint to it.

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Brushless DC Motor Introduction | AddOhms #21

Wed, 26 Jul 2017 13:20:18 +0000

The first part of the tutorial looks inside of a Brushless DC Motor, or, BLDC. Then I show a discrete transistor circuit that can drive one. Of course, you’ll need a Microcontroller like an Arduino to drive it! Lastly, I briefly talk about an ESC. Overall, a BLDC is better than a Brushed DC Motor (talked about those on #20) because: There are no brushes to wear out No sparks when the motor spins You can get way faster RPMs out of a BLDC. Check out the AddOhms #21: Brushless DC (BLDC) Motors. Show notes are available here.

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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.)

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’!)

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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.

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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.

AddOhms #15: Pull-Up Resistors (and buttons)

Mon, 10 Aug 2015 13:00:05 +0000

The latest AddOhms looks at why you need a pull-up resistor when using push-buttons. This video goes into what happens when you leave a pin floating, what a floating pin means, and how the pull-up works. You can get more information about the video on the AddOhms Episode page. Pull-Up Resistors can be a difficult topic to understand. That’s why I made this video. This tutorial is the 2nd time I’ve made a video on pull-ups. Despite being a single resistor, it can be a difficult topic for new hardware designers to understand. The pull-up video was the first video tutorial I ever made. In fact, the YouTube version uses YouTube’s “stabilization” algorithm, which gives the video a very warped feel.

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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".

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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.

AddOhms Electronics Tutorials DVD Now Available

Wed, 25 Feb 2015 15:12:56 +0000

When I was in elementary school, I remember Ms. Coker telling us we needed to memorize our multiplication tables because we wouldn’t always have a calculator. Years later in college I was told, “learn to use the library, it’s not like you can carry the internet in your pocket.” Buy On Tindie Seems strange that I always carry 3 devices on me that do both. Today a generation of people are growing up with the mass of all human knowledge available to them from birth. No formal education is necessary. And the only need is a modern device with WiFi.

Behind the scenes of AddOhms #11 (MOSFETs)

Thu, 24 Jul 2014 14:00:40 +0000

The 11th AddOhms Video is live and the subject is What is a MOSFET, and how to use them. This turned out to be the longest video I’ve made so far. In fact, I probably should have broken off the power dissipation part, but felt it needed to be addressed. I think many non-engineers look at a MOSFET (or regulator) datasheet and see a huge power value or current rating, but not realize you need a heatsink to achieve them.

"Post your code" to the style of "Let it Be"

Mon, 09 Jun 2014 15:00:06 +0000

A friendly reminder video to everyone asking for help in a programming forum. Lately I’ve been looking for ways to expand on the content in the AddOhms YouTube channel. One of the thoughts I had were taking some of the hard engineering lessons and turning them into a “Public Service Announcement”. You know, like those short films that would run on TV after school or NBC’s famous " The More You Know." Not something so dry, but something at least a little entertaining.

AddOhms #10: BJTs as Transistors

Fri, 09 May 2014 11:30:15 +0000

Every Addohms project follows the same pattern. About 80% of my original idea makes it into the video while the remaining 20% I make up on the fly. Of course, when I do that, I spend 80% of my time on that 20%. AddOhms #10 on BJTs is no different.

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…

AddOhms #8: LEDs and Current Limiting Resistors

Mon, 10 Feb 2014 12:00:49 +0000

The idea for AddOhms #8 has been around for quite some time. I’m always trying to find ways to explain why current limiting resistors are necessary. So while working in the shop one day, I decided to play with some LEDs and a bench-power supply. Then I decided to record what happens.

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.