WATTCHER, TWITTERING kill A WATT plans posted

You probably saw [Phillip Torrone] and [Limor Fried]’s twittering kill A Watt earlier this week. It was an entry in the Core77/Greener Gadgets design Competition. We saw a little bit about how it was assembled, but now they’ve posted a full guide to assembling the hardware. Each kill A Watt gets an XBee radio that transmits back to a receiver that logs the power usage. The tough part when putting this design together was the XBee required 50mA when transmitting. This is well above the kill A Watt’s internal power supply. They remedied this by adding a 10,000uF supercap to act as a rechargeable battery. The daily twittering is just a side-effect of the project. The kill A Watts transmit every 2 seconds, so you’ll get a very accurate report of your power usage. This is a terrific project for renters who can’t permanently modify their power infrastructure. Each kill A Watt can support quite a few appliances considering that they’re rated for 15A, ~1800W.