Four Current Flow Myths Addressed

Just what is "electric current flow?"

what is current flow?

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

via Wikipedia

Everyone probably knows Ben Franklin. He discovered electricity, of course! Yet, he didn’t. Franklin was the first to prove that lighting 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.

This convention creates a lot of confusion around conventional and electron current flow. It’s a concept that has been covered by many others and may even be covered by an Electronics Tutorial Video Series in the future.

Instead, I want to explore some common current flow myths even I believed at some point.

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Switching Voltage Regulator Tutorial

AddOhms #18 covers the basics of switching voltage regulators

Switching Voltage Regulator - AddOhms Banner

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.

To understand the basics of a switching regulator, I released AddOhms #18 this week. This is video tutorial dedicated the Switching Voltage Regulator. If video tutorials aren’t your thing, then keep reading for my written tutorial.

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How to Turn Your Arduino Prototype Into a Manufacturable Product

6 steps from John Teel at Predictable Designs

arduino prototype to product
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.

Developing a prototype based on an Arduino (Genuino outside the USA), or other development kit, is a great first step.  But there is still much work to do if you want to make your product into something that can be manufactured in volume and sold to the masses.

So I’m going to break down the process for you into a few manageable steps:

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Energy Density of 9V battery vs AA batteries

Which is better one 9V or six AA batteries?

9v battery vs AA battery energy density copy r1-01

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’m 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.

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Logic Analyzer Tutorial and Introduction

Want to know if you need a Logic Analyzer?

logic analyzer introduction

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.

For debugging digital signals, a popular option is to use a Logic Analyzer. If you are not familiar with a logic analyzer, or you are not sure if you need one, this tutorial should help.

First I’ll give a simple overview of what a Logic Analyzer does, some considerations when to use one, and then give some terms to know when looking at them.

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Arduino to ESP8266, 5 reasons to switch

Move over Uno, there's a new board on my bench

Adafruit ESP8266 HUZZAH Feather

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.

However, when it came to day-to-day “make something quickly” type work, I relied on my Uno. But not anymore. Here are the 5 reasons the ESP8266 is my go-to Arduino board.

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MQTT Tutorial for Raspberry Pi, Arduino, and ESP8266

Send MQTT messages between 3 different platforms

mqtt tutorial

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!

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HDDG11 Capacitors and FootprintsHardware Developers Didactic Galactic is a group for hardware designers, hackers, and enthusiast to discuss hardware-related topics. HDDG11 (or 0xb) featured a presentation from SnapEDA CEO on Footprints and my presentation on Capacitors.

Titled “They’re JUST capacitors?” I used content from my time as a KEMET Field Application Engineer.

Overview

In the presentation I address the common myth or guideline: “capacitors should be derated 50%.” Comparing Aluminum, Ceramic, and Tantalum we discuss why each technology has a de-rating associated with it. Turns out, they all have different reasons to de-rate.

Additionally I give a brief introduction to Supercapacitors. (You’ll note that it is spelled with one word…) The key to understanding what makes them “super” relies on how they achieve the common capacitor structure of electrode plate, dielectric, electrode plate.

Download PDF (11mb)

Tools mentioned at the HDDG11 Presentation

For Questions

Questions related to capacitors or this content, should be asked through the KEMET’s Contact Us.

MQTT Introduction and Tutorial Part One

Message Brokers and why your IoT device should use them.

MQTT Introduction Part One

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.

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Raspberry Pi GUI Tutorial

Use Qt and Python to make an easy to use Pi App

Raspberry Pi GUI Tutorial

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

Image from adafruit.com

This screen is what I needed in 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?

Python is popular in Pi projects, so I decided to stick with it and find out what GUI toolkits are ready to go. “Ready to go” means they install easily on Raspian and work well on the Pi.

Here is how I got Qt5 for Python up and running to create a Raspberry Pi GUI.

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