Making Project #1: The Noise Toaster

One of the making projects that I did over last summer was to put together a Noise Toaster.  I built this thing from a kit (printed circuit board, faceplate, about a bazillion components), and then I modified it slightly so that I could plug a guitar into it.

Anyway, it was working pretty well until about a month ago when the White Noise stopped functioning.  Everything else still worked, so I figured that there was probably a short somewhere.  I also hadn't ever installed a battery clip , so the 9V battery inside the box was loose and clanging around.  If figured that when I opened the Noise Toaster up to fix, I'd just screw a battery clip at the same time.  Piece of cake.

As it turned out, I couldn't actually get the battery clip screwed in because the case was too small to get my screwdrivers in at a good angle.  Instead of screws, I opted to use some adhesive/velcro strips.  I have used these before to attach picture frames to walls, and they work pretty well.  It isn't as permanent as using screws, but it gets the job done and it's really easy to install.

The next thing I did was pull the circuit board out and start looking for problems.  I found a diode that had been bent so that its bare wire was touching the back of a potentiometer, but bending it back into place didn't fix the White Noise problem.  I spent a good five minutes scanning the front and back of the circuit board, but couldn't find anything that looked wrong.  After testing the various knobs a few more times though, everything stopped working!  Yikes!

My first thought was to check the battery using my multimeter.  The 9V battery was still showing 7 Volts of potential difference, so it still had quite a bit of juice left.  Since the problem wasn't the battery, it must have been a loose wire, but if there was one, I couldn't find it.

Well, after letting the Noise Toaster sit for an hour, and not coming up with any ideas, I decided to try a new battery anyway.  And guess what?  That's right, everything worked great. All the noises and lights came back.  The white noise maker started working again.  Hurrah!

I was actually pretty fortunate that it only took me an hour or so to figure out the problem.  Anyone who takes up electronics as a hobby is guaranteed to have projects that just don't work, and it can take a very long time and a lot of searching to discover the problem.  Sometimes the solution will just come to you, and sometimes you'll have to test every single stupid component before you find the problem.  Let's all learn a lesson from the Noise Toaster though, and make sure that the first thing we always check is the power source.  Even if you think your batteries are pretty good, or that your AC adapter is plugged in, you should double check just to be sure.  You'll probably save yourself a lot of time and energy.

Noise Toaster Circuit Diagram - Just in case you were interested:)

Just for fun, I plugged a guitar in to the Noise Toaster and ran it through a practice amp.  The audio quality is very low, because I recorded it with an iPhone, but you get the idea.  All of the distortion is coming from the Noise Toaster, but as you'll hear, it only sounds decent if you are playing lower notes.