ELECTRICITY AND TEMPERATURE MEASUREMENT

[Andrew Vevers]

I just managed after a lot of experimentation to get my electricity data logger going. I have a Microlink 826 which takes pulses from gas, water and electricity meters and stores the data for later download to PC.

It also has software to process data in real time on the PC, but my computer draws too much power to leave on all the time.

I tried three devices to get a signal from the red flashing light on my electricity meter. One was the Velleman MK120 IR kit, modified as per the Bwired site. It would flash in time with the meter but whenever I tried to connect my data logger up it stopped working.

I'm now using the MK125 daylight sensor. It drives a small relay and you can connect to get a signal in the light rather than dark part of the cycle. You have to remove a capacitor and this is explained on the Velleman web site. It's less complex and cheaper than the MK120.

My question is how do I measure and log outdoor temperature? My logger receives pulses but will also send out a pulse to a device such as a variable resistor. I'm guessing that a temperature probe is some form of resistor and the resulting voltage is what is recorded and translated into degrees.

Where do I get an outdoor quality temperature probe without having to buy a load of extra electronics? Most of the devices I've seen are stand alone weather stations or hand held temperature meters.

The idea I have is to relate gas use to outside temperature and electricity to time of year. A big chunk of my electricity is used for lighting. I'm working on my light bulbs but I've got a lot of GU10 spots and low energy alternatives are not cheap.