They call it “trouble” shooting for a reason

Over on the Hands-On – Make: Electronics blog, our new best friend, Jim Kelly, continues to blaze his way through the experiments in Make: Electronics. It’s really fun to watch someone learning out loud.

In Chapter 2, Experiment 8, Jim learned an all-important lesson in electronics, the need to be persistent in troubleshooting a problem. When you’re neck deep in it, it can be a frustrating and time-consuming process, and you frequently think you’ve examined everything that possibly matters. Then it turns out to be something so obvious you missed it, or so obscure, you never would have even considered it (and you only tried it in fit of desperation). The benefits of persistence is not only the resolution of your problem, but the thrills and “ahas!” you get to enjoy when you’ve finally figured it out.

Here’s how Jim tackled, and finally resolved, his problem:

So, enter the breadboard. I’ve been wanting to learn how to use one of these for a long time… I always thought they were complicated (look at all those holes and rows and columns!) – what a pleasant surprise to find out that this thing isn’t all that difficult to use.

Be sure to read over the sections on the fundamentals of capacitors/capacitance – as well as the warnings about attaching certain capacitors to the breadboard incorrectly. It’s good stuff, but we all want to get our hands on the breadboard, right? Thankfully the author isn’t going to have us tear apart a breadboard – they’re not cheap!

So, after examining the circuit a few more times and comparing it to the drawing on page 66, I definitely understand how the breadboard facilitates building this circuit. I took all the components, inserted them into the breadboard, supplied some power, pressed the button… and…. nothing.

Zip.

So, here’s where some patience and common sense come in. First, we know this circuit works, right? Without using the breadboard, I was able to build this circuit using clips, so it’s got to be something I’m not wiring up correctly. So…

1. I checked that my two LEDs were inserted properly – long wire to positive side of circuit. Check.

2. I checked that the resistor was a 1k resistor. Check.

3. I checked the polarity of my capacitor – long wire to positive side. Check.

4. I verified all the wires were inserted into the proper rows/columns that matched up to the relay’s 8 pins. Check.

5. I verified that the voltage to the circuit was being supplied by that small jumper wire and that the jumper wire was in the right column where I had the positive voltage (from the AC adapter) inserted – there are two columns, so check this. No problem there.

6. I did the same with the negative voltage side… jumper wire, resistor, and AC Adapter negative wire all on the same column on my breadboard.

Plug it in again… nothing.

Then begins the troubleshooting… I replaced both LEDs (just in case one or both were burned out), I replaced the resistor, and double and triple checked all wiring.

Plug it in again… nothing.

So, if you’ve jumped ahead and watched my two videos, you know I got it working… and you’re probably saying “Okay, Jim… enough! Tell us what the problem was!”

It was the pushbutton. Take a close look at the momentary pushbutton in the photo I’ve supplied here. Notice that it has four little metal feet. All it took was rotating the push button 90 degrees and reinserting and the problem was fixed. That was my problem all along.

Still, I learned to trust my wiring skills… after double and triple checking so many things, I was left with the only component that I had NOT checked.

So, if you’ve got a similar pushbutton and your circuit’s not working – rotate the pushbutton and try again.

Chapter 2 – Exercise 8

In the Maker Shed:


Make: Electronics
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Want to learn the fundamentals of electronics in a fun and experiential way? Start working on some excellent projects as soon as you crack open this unique, hands-on book. Build the circuits first, then learn the theory behind them! With Make: Electronics, you’ll learn all of the basic components and important principles through a series of “learn by discovery” experiments. And you don’t need to know a thing about electricity to get started.