Hmm, my plan for powering an Arduino from the CurrentCost energy monitor has hit a little snag – the idea was to use the 3.8v unregulated supply on pin 1 from the CurrentCost. I could then run either a Xino at 3.3v or boost it up to 5v.

However, as soon as I put any load on that supply, the energy readings on the CC128 display flatline and there’s nothing in the data transmission either. I wonder if I’m simply drawing more current than the display unit has “spare”, which means that it doesn’t have enough left itself to power its own RF module and thus gets no sensor data? Or, it does have enough to power the RF, but not enough to get a signal from the sensor – amounts to the same thing really.

CurrentCost energy readings flatlined

CurrentCost CC128 PSU

Guess I need to go look up how much juice an Arduino Uno consumes …