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Old 11-09-2010, 10:04 PM   #15
mistergreen
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I received the photodiode yesterday. Got to play with it a little. In this picture, I'm trying to find the right resistor for this set up.


A 4.6K resistor seems to work. I'm calibrating the max output to sunlight.. 1024 (5V) is the max reading and sunlight through a window gives a reading of ~900. So I think I got it.

Mounted the photodiode on a electrical cap


Assembled the jar... This nub in the jar is a problem. It casts a shadow on the photodiode.


I moved the diode to the side and gave the plastic a little frost with fine grit sandpaper to scatter the light a little.



Next step is to calibrate these numbers to the PAR readings.
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