From the Speed Dial website:
"Simply put, I wanted to use the phone as a gateway into something different, yet still very social, and enjoyable. Slot cars have existed in one form or another for many years now, and whilst simple, they invoke a great sense of play.
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Ultimately I hope people leave the project thinking differently about play and the telephone, as well as having a great smile on their face.
How it's Done
The project takes advantage of Asterisk, the open source PBX, to take in the phone data and spit that out to a Java based soft phone. This soft phone takes in a SIP stream which I then take amplitude data from. I use that data, scale it a bit an send it serially to an Arduino board.
The circuit itself is quite simple. It uses a transistor to send voltage to the track (12v DC), and I use the incoming serial data to PWM..this allowing for a difference in speed. "
Want to learn more? Contact Christopher Paretti - chris@cell-ular.com