TorrentMeter – A steampunk bandwidth meter

This project is a meter that measures your Internet connection bandwidth using an antique gauge. It is based on an old voltmeter and on Arduino board. A perl script is getting the information from a Linux router and send it to Arduino via serial connection emulated by FTDI chip. The Arduino convert it into a pulse width. To drive it full scale it needs about 10V and 150mA and that too much fro Arduino to handle, so it uses a switching amplifier made from transistors.

http://www.electronics-lab.com/blog/?p=6806
http://blog.skytee.com/2010/11/torrentmeter-a-steampunk-bandwidth-meter/