Light sensor parameters

Hi I’ve been searching through the forums for the answer to this question with no luck. I understand the light sensor is using lux to measure our lights to let us know if there off or on based upon how their calibrated in the beginning. I also understand its recommended to put a shade over it to allow more accurate temp and rh readings. What id like to know is what the lux percentage is actually reading. For example if I didn’t have the shade on and calibrated to that what is the maximum lux and minimum lux. Basically the parameters the meter is using to create the percentages. I appreciate the way it functions now was more or less curious. I know lux isn’t very good for tracking led lights as it differs in values according to spectrum but knowing your Kelvin(spelling?) Temperatu re which you can get a decent idea of on some cell phones. Or just knowing what diodes you have and the manufacturers information you can figure out ideal lux as a guideline for light levels. This will probably be irrelevant when the pro comes out but I’d like to know anyway. From what I’ve researched in my situation its close to 1000 lux is about 10ppfd. So 10000 is 100 and so on. After about 1000 ppfd photoinhibition sets in strain dependent unless using co2. Anyways any information you can provide me would be great thanks on advance.

Phones are very inaccurate for our purposes. IMHO :slight_smile: I use a Digital Lux Meter by DR.meter, Model LX1330B, $32 at Walmart
I have a HLG550 R Spec and I use the Efficacy rating (PPF) and HLG’s web site LUX CONVERTER PAGE to get my PPFD.
You MUST know your lights efficacy rating from manufacture. If they are decent light it will be listed in your specs.
I was surprised how far off the phones are. If u really got a few $$$$$$$650+ buy a APOGEE PAR meter

Example My HLG550 has a PPF/efficacy of 1256.92 . Find HLG’s light that most closely matches your lights PPF and scroll down till u find that light’s calculator.
Enter YOUR LUX value from your LUX meter into the calculator, hit CALCULATE and it will give you your lights PPFD output.
I adjust my light intensity or move closer/further from/to lights 1st. (I don’t move my light, it its fixed 10" from tent ceiling and plants on crates when shorter) .
I then adjust my humidity to the temperature to get my 1.2 VPD

It may seem complicated, its not really. Once you get this your plants will like you and it will be easier for you to set your environment.

Yeah I was actually talking about the hlg conversion and knowing the color led it was. I have the pro coming also so I’m not really interested in lux at the time I’m not willing to drop 500 bucks on par meter either. I know apogee makes the industry standard for par meters I’m hoping the pro is able to be a decent substitute fingers crossed. Heh. I’ve got my vpd at 1.2 stable currently was just more curious what their parameters are just for shits and giggles I guess. It serves its function as far as letting me know if my photo period is correct so I’m happy. Thanks for the info anyways I’ve been researching led tech for months to understand the intricacies if only to be a better consumer when I upgrade my leds again. Your 550 is similar to what I’m running in my bloom tent I have a spider farmer sf4000 and a 240 watt Chinese quantum board 288 both lights have lm301bs. Hlg’s are better binning but the ppf is pretty similar anyway slightly less efficient by 5 to 10 percent. Spectrum. Slightly different being a mix of like 70 percent 3000k and 30 percent 5000k with some added 660nm and 4 770nm irs. All in all pretty similar though. Check out migro on YouTube and and look at the light calculator their very useful tool. It gives you the actual usable ppf of a fixture in a real world scenario. The ppf of all leds is less efficient then what is claimed from losses of photons in a tent or open space environment. I think most importantly is just achieving around 800 ppfd through the entire canopy once into late veg and bloom. Have a good one.

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LUX is simply the best measurement for checking how effective your lights will be on plants. There are also many other factors to be considered when taking an accurate light measurement with a proper instrument such as lens angle and distance.

Pulse Pro will have an advanced light sensor capable of PPFD and spectrum readings. Even so, the Pro will need to be used as a handheld to get the proper lens angle for taking an accurate reading – this is why Pro has a rechargeable LiPo battery so you can take it off the wall for light sampling.

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