Energy Consumption RRD Logger (CC128/EON Energy)

MISCELLANEOUS -️ October 1, 2010


Many UK energy suppliers are giving away 'free' energy monitors to their customers. I think this is a great idea.

My current supplier, EON-UK, is using the ENVI monitor from CurrentCost which is supplied with a USB cable for connection to the computer. Through this connection, it is possible to make a much better logger than the device itself shows.

The supplied cable is actually an all-in-one USB->UART->TTL convertor. The drivers for it are already present in modern Linux kernels so for Linux it's plug 'n' play.

Here you can download a few programs which:

  • Connect to the serial output of the CC128 monitor, capture the data and save it into a RRD
  • Produce charts of the captured data.

The main program is written in Python using documentation from the website The message parsing part is in a separate class which you can use for your own programs.

Although these scripts are standalone, they are designed to form part of an overall solution so don't expect any fancy user interfaces.

This script supports multi-channel/multi-appliance setups automatically and includes an example of a 3-phase setup:

3-phase output example


Now updated to support multiple channels and multiple appliances. The command line arguments have changed so please check before upgrading.