The Mystery Beeping Prank is a device hidden in a hollowed out book that beeps intermittently at different frequencies. I made this because I am surrounded by a lot of incredibly creative people who have a penchant for pranking one another, and this seemed like the most subtly annoying thing that I could think of. In fact, I imagine this will be outright maddening for all those not in on the joke. Hopefully these people will have a good sense of humor about it, and not be too permanently scarred by the experience. It is all in good fun, after all.
Step 1: Go Get Stuff
(x1) Arduino micro (Radioshack #276-258)
(x1) 40 pin socket (Radioshack #276-1996)
(x1) LM386 audio amp (Radioshack #276-1731)
(x1) 220uF capacitor (Radioshack #272-1029)
(x1) speaker (Radioshack #273-092)
(x1) Prototype circuit board (Radioshack #276-150)
(x2) AA x 4 battery holders (Radioshack #270-391)
(x1) Rubber cement
(x2) 12" x 9" x 1/4" wood blocks
Step 2: Socket
Make sure to leave room for the LM386 chip.
Note: The schematic shown here applies to the next 7 steps.
Step 4: Capacitor
Solder the negative lead to any free terminal.
Step 5: Wiring
Solder pin 6 from the Arduino micro to pin 2 on the LM 386 chip.
Connect pins 3 and 4 on the LM386 to ground, and pin 6 to power.
Note: I made some of these connections with solder below the board.
Step 6: Battery Packs
Connect the single red wire to the 12v power rail, and the lone black wire to the ground rail.