OK now I understand your 65 factor, I assume that you pulled the 60 and 70 numbers from a chart someplace?
I still don't understand the calibration. Isn't the meter suppose to zero out with the cap on it, no light thus 0 LUX.
Wouldn't you just be able to take a reading under your lights and then divide by the correct factor to get your PAR?
So you take a reading and you get a lux of 40,000 (or where did the 40,000 come from) and divide that by your factor of 65 to get the 615. Drilling a hole in the cap limits the amount of light hitting the sensor, and the tape is acting as a magnifier? This is the part I'm just not understand why/what is happening.
Have you tried any other meters. I saw a couple others that say they have a wider spectral sensitivity to catch more of the lower blues and higher reds but they don't show a graph. A reviewer posted a picture of the instructions for the one you have and the graph shows that most of the sensitivity is focused between 500 - 650 nm, so I was wondering if it is capturing all the blue in the 450 area on these COBs and the reds that venture to 700 and above.
I've never used one of these meters so perhaps I'm missing something.
Man, the premise of this ( lux with hole) is so you can read on the fly, just like the par meter. Yes, it will read O lux with the cap on, but hole lets light into the meter. lol, sorry man, i had to chuckle on that one bro. The tape acts as a diffuser, simply put. I got the 40,000 lux by putting the meter under the Cobs.
You want a picture by picture procedure for this explanation? I have some time, i can throw some things together to show you what i mean.
Now, as far as the whole blue/red/white thing. I dont care about all that. I know these cobs have the correct spectrum to produce fantastic fruits, all im looking for is intensity figures. And thats exactly what this does for me.
I have a plan to buy a PAR meter from amazon, calibrate my lux meter, and send it back. I just need it for 10 minutes. Im not changing my light rig, i love it, and its perfect for my needs. Then i can get a true reading.
But i can tell you this much about it all. I had a Perfect sun mini, and my hacked lux meter gave me the exact PAR reading, so take it for what its worth, and i think spending $125 on something I dont really need, is wasteful spending, just to get a "Sense" of what the PAR is. From what Ive read, the HydroFarm PAR meter is not even true, and bounces around, and some also said its just a Lux conversion anyways. WAY overpriced.
You understanding this bro? At the end of the day, PAR numbers and Lux numbers are just intensity values of the spectrum coming out of the light source. We know the spectrum, we need intensity values, just to simply adjust the light distance.