Hi there,
I'd like to count pulses from the LED on my electricity meter. Pretty easy if I had a good power supply but I want to run on a coin cell battery. The tricky bit is I can't find a photo diode with a lower enough power consumption. I'm trying to work with a budget of 10-20uA (aiming for more than a year battery life). Lowest photo-diode I can find is 800uA which isn't going to work for me.
So I had the idea to use a photovoltaic light detector instead. ie. Use a sensor that converts the LED output into a tiny DC current without draining the battery.
Is this going to be possible? Does an LED emit enough light to activate a photovoltaic cell? If I could find a photo-cell that could register a LED pulse then I'd feed those pulses into an PIC interrupt and that would be my counter.
Any pointers appreciated.
Cheers,
D.