Wouldn't things go so much more swimmingly if there was an unending torrent of high-pitched beep going on the background? Sure, your predicament may be boring and now even extremely annoying, but knowing that you're secretly the cause of it all will give you something to smile about on the inside. Oh yes!
This super-easy instructable can be built by people with monkey hands, like myself, and with very little electrical knowledge and no soldering skills whatsoever to provide literally hours of annoyment.
Bastard son of the LED throwie, the Buzzer Throwie is basically a loud buzzer connected to a small button battery which will power the device for over 8 hours and being connected to a powerful rare-earth magnet will allow you to secret the device under desks, on metal ceiling pillars. Pretty much in any inaccessible magnetic place you can find in a modern lecture theatre or classroom.
Ok, here's a list of parts you will be needing. They are all available from the web. I use dealextreme for much of it, since they are cheap and I like them, but ebay does just fine as well. There are no sophisticated parts in this project, it's all rather ghetto.
1 x 9mm rare-earth magnet. Very small and very powerful. Any size will do, but 9mm seems to be powerful enough to stick this throwie.
1 x 3v button cell battery. You can use 2 x thinner 1.5v ones, but that's more parts to be assembling and add unnecessary complexity. Remember, this is an instructable for my cack-handed brethren.
1 x 5v piezo-electric buzzer. I got mine from ebay. They run from 1.5v to 5v. It's louder with more volts, so the closer you get to 5v then the more annoying it will be.
1 x roll of Scotch tape, or similar. I just had Scotch tape to hand, and you don't even need scissors to cut it, so I just used that. Any other tape would work just fine though.
Now, to assembling this thing
Step 1: Gentlemen, Prepare Your Buzzers!
We will be removing the wires from the buzzer and the shrink-wrap contact sleeves. So just snip the wires either with scissors, some pliers (the best way) or your teeth (not the best way as you might end up eating the buzzer. Do not do this as you'll be needing it later on. And it might kill you).
Make a note of which end is which, but if you don't then don't worry as I didn't and I just connected it up to the battery until it worked. It didn't seem to do it any harm.
Step 2: Assemble It
1. Place the buzzer at the bottom, upside down.
2. Place the battery between the buzzer contacts and squeeze together until it buzzes. Annoyingly. Very annoyingly in fact after a few minutes.
3. Attach the battery carefully to the top. If you just drop it then the battery can crack, as they're fragile little things.
4. Wrap up the whole thing in your tape, making sure that the contacts are still making a good connection with your battery.
5. To stop the buzzer squealing at you, you can temporarily tape the end of it up and remove it when it comes to deploy time.
Step 3: Deploy
We have metal roof beams in our office and I have successfully deployed it here. I have 20 co-workers who agree that it's not a good thing to be working beside for 8 hours. The little AG13 battery lasts in excess of 8 hours at annoying volume levels and decays steadily after this.
To be environmentally friendly, please make sure that you put this in a hidden, but accessible place so you can retrieve it later. Afterall, there's about 50p worth of parts in your device and you can use it again and again! Don't foul up your nice environment with nasty battery chemicals. You'll end up eating or drinking them further down the line anyways.
Step 4: Other Thoughts...
Well, that's it for my first instructable. It's pretty dumb and lacking in artistic flair and skill, but I've been visiting this site for ages now and haven't contributed anything yet, so I thought that something is better than nothing.
Let's hope I don't die (at the hands of my co-workers most likely) before my next one as this would be a pretty dismal way to be remembered.