LF Apogee MQ-200 PAR Meter

[hillegom]

In the link that I have in the post, It describes the sensor SQ 120.
The sensor when illuminated, sends out millivolts, which of course could be read with a multimeter. You multiply the millivolts times 5 and you have the par. I don't have time to reread it now, but that is what I remember.
So if you have a good multimeter, all you need is the sensor.
At present, I do not have good lights. So when I buy new ones, then I will buy the sensor