Logging Household Power Usage From the ClimateSmart Power Monitor

The Plan

Our home is equipped with a wireless power monitor provided by the Queensland Government through the ClimateSmart Programme. The receiver provided is fine for monitoring instantaneous power usage, and daily, weekly or monthly averages, but we soon realised that we really need to be able to see usage graphed over time to understand our power consumption pattern. It is of limited use to know that yesterday you used a lot more power than usual unless you can pin-point the source. If we could graph the useage over the day we could see when and for how long the high-load periods occur, and this will help us retrospectively identify the cause of the extra usage.

Identifying The Equipment

At the time of writing the FAQ on ClimateSmart's website indicates they have installed three different kinds of energy monitors which they identify as follows.

	Owl: Owl Energy Monitor Product Guide
	Efergy: Efergy Energy Monitor Product Guide
	Efergy2: Efergy 2 Energy Monitor Product Guide

From these illustrations and the Efergy Website I concluded that our receiver is an Efergy Elite Wireless Monitor .

Intercepting The Data Stream

A bit of research turned up this interesting article describing how to decode the radio signal from an Electrisave usage monitor. This gave me some confidence that I could decode the data stream if I had the right radio receiver.

I determined by inspection that the radio chip in the Efergy receiver was an A71C03AUF, manufactured by Amicom and I found the Data Sheet for this chip.

After reading the product sheet for the A7103, I am hopeful that I can build a compatible receiver and decoder based around the RFM22-S2 RF Transceiver Breakout Board available from Sparkfun Electronics, interfaced to a PC using an Arduino Uno microcontroller. The datasheet for the RFM22 is available here.

What's Next?

Components have now been ordered and received, so read on to page 2 for the next steps.