Tweet-a-Watt Build a wireless home-power monitoring system

Watch me make a Watt-watcher

This project documents my adventures in learning how to wire up my home for wireless power monitoring. I live in a rented apartment so I don't have hacking-access to a meter or breaker panel. Since I'm still very interested in measuring my power usage on a long term basis, I built wireless outlet reporters. Building your own power monitor isn't too tough and can save money but I'm not a fan of sticking my fingers into 120V power. Instead, I'll used the existing Kill-a-watt power monitor, which works great and is available at my local hardware store.

My plan is to have each room connected to a 6-outlet power strip which powers all the devices in that room (each kill-a-watt can measure up to 15A, or about 1800W, which is plenty!). That way I can track room-by-room usage, for example "kitchen", "bedroom", "workbench", and "office".


I spent about 10 minutes on this diagram... can you tell?

Each wireless outlet/receiver can be built for ~$55 with a few easily-available electronic parts and light soldering, no microcontroller programming or high voltage engineering is necessary!

You can see my setup including graphs and reports at http://twitter.com/tweetawatt

If you'd like to build one for yourself

  1. Buy a kit: get all the parts you need, there's a starter kit at the adafruit webshop
  2. Make: turn each Kill-a-Watt into a wireless power level transmitter
  3. Software: Download & run it on your computer to get data and save it to a file and/or publish it

If you want to know how it was made, check out:

  1. Listen: write simple software for my computer (or Arduino, etc) to listen for signal and compute the current power usage
  2. Store: Create a database backend that will store the power usage for long-term analysis at http://wattcher.appspot.com
  3. View: Graph and understand trends in power usage

Check out the latest readings at http://wattcher.appspot.com

May 17, 2011 20:07