The Adafruit Web site, which sells the Tweet-A-Watt starter kit, calls Tweet-A-Watt a "moderate/advanced" project. Here's an overview of the process so you know what to expect if you want to dig in (for very detailed instructions, look at the Tweet-A-Watt Web site).
- Kill A Watt power meter (about $20)
- Tweet-A-Watt starter kit ($90), including two XBee wireless modules, two XBee adapters, an FTDI cable and a bunch of basic electronics parts
- Soldering iron
- Flush/diagonal cutters
- Helping Hands stand with magnifying glass
- Sticky foam (the crafting product, not the nonlethal weapon)
Once you have everything assembled …
Building the Receiver
At this stage, you'll solder one of the XBee adapters together and then make sure each XBee module can communicate with the adapter. You'll download a piece of software (Windows-only!) to set the communication settings.
Upgrading and Configuring
Next, you'll do some software work on the XBee modules -- no hardware manipulation here. You'll upgrade the firmware on both modules and then configure the transmitter module to pull data from specific pins on the Kill A Watt, send data at certain intervals and talk to the adapter on certain channels. Again, you'll be using a piece of Windows-only software to assist you.
Building the Transmitter
To build the transmitter setup, you'll be doing a bunch of soldering, working with capacitors, resistors, wires and heat shrink. You'll also be opening the Kill A Watt case and drilling a hole in it to insert a new LED for the Tweet-A-Watt.
Running the Software
Finally, you'll set up the software to accept the energy data and publish it to your Twitter account. You'll be using a programming language called Python to make some modifications to a script and run a few commands (all fully written out for you in the instructions).
If you don't already have a Twitter account, you'll have to set one up here. Once you plug your Twitter username and password into the script, you're good to go.
This is the most basic setup: Tweeting the data from a single Kill-A-Watt. With some additional parts and programming tweaks, you can arrange the system to compile and report data from multiple outlets, so you could get a whole-home energy report going on your Twitter account if you really want to. That might get expensive, though, since the parts for each add-on outlet run about $60.
If this type of work isn't up your alley, you can probably just wait a little while and buy one pre-made. The designers made Tweet-A-Watt's plans open source, so anyone can make a commercial product out of the concept. And if Tweet-A-Watt takes off, we could start seeing lots of devices that use the power of Twitter for good.
For more information on Tweet-A-Watt and power monitoring, look over the links on the next page.