So the other day I was at the local electronics surplus store waiting to meet up with someone. I didn't have anything in particular to buy, so I was left wandering the shop for a couple of hours wondering what I could possible get and build. budget was tight this time around, but then I saw it:
...and the idea started forming.
just add power... perfect! I'll need a project box, one this can fit inside... but indistructable. found one:
wire this to the toggle switch and a 9v battery and relay and siren, and we're set for all sorts of prankster fun!
Oh, but there probably *SHOULD* be a way to actually turn it off properly without having to open it or trying to smash it. Ahh, here we go:
slap it all together, and we're done! actually, it wasn't quite that easy. Figuring out the circuit without looking anything up or just up and copying a diagram someone already did was a bit tricky; like solving a logic puzzle. the end result is what I'm sure is a very common design and nothing original. and I'm sure if I just googled around for only a few mintues, would have found the exact thing I needed, spelled out for me. but where's the fun in that? actually, staring at the parts trying to figure it out wasn't too fun either, but the result seemed more rewarding.
But, if anybody else wants to make something like this, I took the time to draw up the schematic and make it available for you (not to mention also for me, for future projects should I forget what I did here...):
And now for the finished product:
It's a nice little box. feels very sturdy, easy to use. easy to turn on. only turns back off with use of the key.
I had a bunch of barrel key switches from old computer cases (keyboard locks) but the problem with those is that none of them are actually specific to any one key, as long as a key fits, it would turn.
due to the "sensitive nature" of the post 9/11 era, I will be unable to make maximum use of this devices in a number of ideal locations (mainly public) such as: Bus, Subway, Elevator, Store or most any other places where a random stranger would be most likely to turn it on out of curiocity. THIS IS NOT A BOMB! Your safest bet would be to just leave it on your desk at work and people who come by to talk and fiddle with your stuff can learn not to be touching your stuff. This simple circuit concept would actually work for a number of "Don't Touch My Stuff!" applications. replace the toggle switch with a capacitive touch sensor for a number of things you don't want people touching, wire a normally-open micro-switch to your desk drawers, transistor to your capslock LED, etc... Just put the keyswitch in its own enclosure, mounted to your desk.
also, the fact that the enclosure is all metal may discourage people from turning it on, if they think it might start shocking them or something.