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

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
  3. View: Graph and understand trends in power usage

This guide was first published on Dec 03, 2014. It was last updated on Dec 03, 2014.

This page (Overview) was last updated on Feb 26, 2013.

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