This year’s Greener Gadgets Competition ended on February 27 where tons of awesome green gadgets were judged. The big winner this time was the Tweet-a-Watt, a modified Kill-a-Watt that tweets your daily power usage. A Kill-a-Watt is a great product that has been out for quite a while and tells you how much power you are pulling from a particular outlet. This is great to use if you want to find out how much power your devices are using while powered on or even while they are supposedly powered off. The Tweet-a-Watt goes step further and automates the process of taking this information, transmitting it wirelessly, and getting it online for you to monitor. Their modifications of the Kill-a-Watt are open source and free for anyone to use and modify. If you head over to the Tweet-a-Watt’s twitter page you can see how it works and how they track their power usage over time.
Using “off-the-shelf hardware”, we have modified a Kill-a-Watt(TM) power meter to “tweet” (publish wirelessly) the daily KWH consumed to the user’s Twitter account (Cumulative Killowatt-hours). We are releasing this project as an “Open source hardware” project – in other words, anyone can make these, modify them and make a commercial product from the ideas and methods.
Here’s how it works: The modified Kill-a-Watt uses a “super-cap” to slowly recharge itself. Once there is enough power it turns on the Xbee wireless module which transmits the data to a nearby computer (or internet connected microcontroller, like an Arduino). Once the power usage for the day is recorded it uses a predefined Twitter account (it can be your own) to publish your daily KWH consumption for the day. Multiple units can be used for an entire household.
I’d highly recommend heading over to the Greener Gadgets Competition home page and checking out all the other cool gadgets that were in the competition.