Adapted from Jibble, I have been recording data in “RRD”, a round-robin database in a single file. Initially, I didn’t have a computer on 24×7, so added some cheap and tacky code to pull the historical data from the current cost meter and log that. A couple of weeks after buying the current cost, I realised I couldn’t live without live readings, so bought the Viglen MPC-L.

View code.

Part of that code runs “colours.pl” with the current power consumption, which sends a message to the arduino telling it to change the ambient light’s colour to a colour that depends on how much power the house is eating up. More about that shortly.