Matt Meerian hacked an old intercom into a masterpiece by stuffing it with some electronics.This Ferris Bueller’s Day Off Joke Intercom System has the ability to play MP3 audio tracks with the touch of a call button. The entire thing is controlled by a central microcontroller and the attention to detail by using the old NuTone intercom helps pull off the effect. If you are interested in playing with a similar creation there is sample code and a schematic available.

"The hardware is centered around a "Vinculum VMusic2 MP3 player" (that’s a mouthful). The Vmusic2 is the gray box in Figure 3, it has the rainbow wires. The Vmusic2 is from a company called FTDI chip and makes playing an MP3 file from a thumb drive as easy as sending over the correct serial string from the microcontroller. The thumb drive is the silver cylinder in Figure 2, it is the back part of a writing pen. One really nice thing about the MP3 player is the ability to jump from one sound file to another. If the project were to use an audio tape player, it would be rather difficult to keep track of where the sound bytes are located on the tape. (And you also have to allow time to fast forward and rewind) The microcontroller is an ATTiny2313 from Atmel running at 4MHz. The ATTiny2313 has 2 Kilobytes of flash and 128 bytes of internal RAM. This is more than enough to read button presses, light the "talk" indicator, and send out a few bytes to the MP3 player. Just about any microcontroller could have been used; even a basic stamp could handle the hardware requirements."