Built to circuit and connected it all up. Bluetacked reed switch to meter and board + cc dev board + 2 AA batteries into small container.
CurrentCost meter connect to Pachube via Arduino. In order to try and get some idea of energy usage and comparison with the electricity usage I am logging KW. The calculations are:
Gas KWhours = cubicmeters * correctionfactor * calorificvalue / 3.6
1 pulse is 0.01 cubic meters
correctionfactor is 1.022646 (from gas bill)
calorificvalue is 39.4 (from gas bill)
So 1 pulse is 0.1119223 KWh.
Average KW = totalKWh * 3600 / measurementperiod(seconds)
I have set the measurement period to 5 minutes – this gives a reasonable resolution. At peak use I seem to get about 1 pulse every 18 seconds. Latest – I now update every 15 minutes – that way Pachube displays every update.