I have been starting to learn to use Eagle, so that I can document my circuit diagrams.  Being quite new to designing hardware I'm learning that it's not good enough to just keep a copy of the source code anymore!  So, here is the very simple circuit that makes up my improved Annoyatron:

It's very simple to knock this up on a small breadboard, you just need the ATMega168, a speaker and a battery, just like this:

Obviously, the ATmega168 is overspecified, but I have a few of them and it's easier to mess around with one type of processor.  I really will try to post the source code and some notes on how to get the source code onto the processor as a program.  Honest.

I think that it's good to keep your hand in with some plain old C programming once in a while.  So I ocasionally mess around with microprocessors. I've been working on an improved annoyatron, with my version it will pretend to be a mobile phone - by playing a simple ringtone. This is what it currently looks like:

 I've used an AVR ATmega168 microprocessor, which is over spec, but I had a couple of them lying around.  In fact all of the other components except for the button cell battery and holder were things that I had sitting around.  What tends to happen is that before I throw anything away, I take it to bits to see if I can remove anything.  Even a salvaged switch can be useful one day.  And it's fun to take stuff apart :-)

So ... what I'll try to do is post more about this - what development tools I've used and what I have discovered along the way.  I'll be sure to refer back to it if nobody else does.