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The power meter Kill A Watt is the basis behind the Tweet-A-Watt gadget. See more green science pictures.

Photo courtesy of Tweet-A-Watt

If you sat at work every day watching your home power bill rise because you left your toaster plugged in that morning, do you think you might start remembering to unplug it on your way out? What if all your hiply green-minded friends were watching, too?

That's the basic idea behind a new power-monitoring gadget called Tweet-A-Watt. The device, developed by Make Magazine's Phillip Torrone and Adafruit Industries' Limor Fried, took first place in the 2009 Greener Gadgets Design Competition. It builds on an existing power meter called Kill A Watt, combining two of today's trendiest topics: energy efficiency and social networking. Tweet-A-Watt is, at the very least, a timely development.

It begins with simple power monitoring -- measuring the wattage an appliance uses by placing a watt meter (like Kill A Watt) between an appliance plug and a wall outlet (see How Kill A Watt Works to learn more). There are different approaches to power monitoring. You can track the wattage (in kilowatt-hours, or kWh) for a single appliance, for a set of appliances, for a whole room or a whole house, and different monitors output the data in varying ways. But the end goal is always the same: Know exactly how much power different electrical devices are using so you can reduce your electricity costs and your polluting, wasteful power consumption.

Tweet-A-Watt takes this concept a step further. In addition to thriftiness and guilt, the device introduces a couple of additional time-tested motivators: competition and peer pressure, via social-networking Web site Twitter.

In this article, we'll find out exactly what Tweet-A-Watt does and how it's supposed to work, and we'll look at the basic steps involved in building one. The big deal here is less the power-monitoring capability and more what you do with the information. Tweet-A-Watt puts your energy consumption out there for all the world to see. Or at least for your "followers" to see.