Hydrofarm par meter

[Red1966]

no........asked the same question awhile back and was told by guod it's just a crappy lux meter with a filter.

You could have asked this?? In one of your countless threads btw........

I have a crappy lux meter. Where can I get that filter?

 

[Red1966]

You got me I'm whiteView attachment 3400919

View attachment 3400920

Posts random stock foto of black man. Lame

 

[Abiqua]

This would be cool and does measure PPFD....over a m^2

http://www.licor.com/env/products/light/quantum_line.html

 

[Abiqua]

I've been wondering for awhile why we can't use this $30 PublicLabs DIY spectrometer. You connect it to their SpetralWorkbench. Calibrate it to a CFL (some consistent mercury vapor signature present in all CFL bulbs, I believe is their theory.). We could then "calibrate" our graphs relative to each other by taking a graph of noon-time sunlight. It would be a process.

The workbench lets you export the data to CSV for a spreadsheet which can be graphed/smoothed. We could all use the same spreadsheet which would do the relative adjustment using the two exported datum. (A spectral reading of an LED light, and a reading of noon-time sunlight taken with a spectrometer that hasn't changed or been CFL calibrated since that sunlight measurement.).

It would be some work. I'm not volunteering to do it. Just throwing out an idea. I have this spectrometer and would be willing to participate. (I can definitely document some gotchas so we'd all use it the same way.).

Have you shot any graphs of your Cree bulbs Az?

That would be interesting to see measured from inside the canopy, or compared against a single bulb graph....That could give me an idea of what specific type nm to search for, to make an LED photometer /Par Meter...

If interested let me know...I really need to get one of those slit kits from public labs and build my own...have all the misc parts

 

[az2000]

Have you shot any graphs of your Cree bulbs Az?

No, I haven't. I don't think it's suitable for measuring intensity. Just quality (spectrum). It seems like it would add the SPD required to calculate the parts chopped off by the Apogee PAR meter(?).

 

[gk skunky]

You could just buy a sensor only from apogee and use it with a multimeter. All the meter does is automatically apply a conversion factor to the mV reading and have data logging abilities.

 

[az2000]

You could just buy a sensor only from apogee and use it with a multimeter. All the meter does is automatically apply a conversion factor to the mV reading and have data logging abilities.

It sounds like the problem is that the sensor doesn't measure far red and blue. If you have an spectral power distribution diagram the true PAR could be calculated (I believe that's what these guys are saying in this thread). But, that's typically a $3-$5k radiospectrometer.

I was thinking the publiclabs DIY spectrometer might be useful. It doesn't seem to have the capacity to measure intensity. In fact, one of its challenges is reducing the light source's intensity enough that it won't overload the sensor, and doing it in a way that won't introduce other colors. I'm thinking photographic filters. Or, different sized aperatures that could be screwed into the conduit junction box. (I've tried that with PVC threaded plugs and a hole drilled in the end, painted flat black.).

I may have confused the topic referring to cross-calibrating using noon-day sun. I guess that's not necessary because the spetraclworkbench's CFL calibration should be enough. If two people calibrated to CFL, then their noon-day sunlight should produce the same SPD.

I think I was going down the path toward measuring/calibrating intensity. But, I dont' think it would work. Maybe a lux meter and the DIY spectrometer could be calibrated together in some way. But, the Apogee sensor would probably be the most accurate way to measure intensity. Then use the DIY spectrometer to see what the sensor doesn't see in order to factor in the additional power?

I don't think I could figure this out. I'm sure others could. All I can provide is some info about how to make the DIY spectrometer as accurate as possible. The "gotchas" I mentioned which aren't discussed in the instruction manual.

 

[gk skunky]

Yeah definitely not 100% accurate but better than the hydrofarm and cheaper than apogee meter with sensor. Just letting him know it was an option. would be nice to have a real deal spectroradiometer.

 

[Greengenes707]

Spectrometer vs spectroradiometer. Easy to mix up, like ppf and ppfd can be. But they are different things.

 

[REALSTYLES]

I got my lux meter today and tested from 18" running at 186 watts 42,900 lux dead center wow I can't wait to test them running at full power(413-433watts)

 

[panhead]

I agree that the meter is gonna end up sitting on a shelf , i played with mine & few times & its been sitting on the shelf ever since .

A $5 Lumen meter will work just as well .

 

[REALSTYLES]

I'll be using mine to test my buddies grow rooms and compare my lights to theirs lol. I have a lot of friend too lol

 

[REALSTYLES]

I just converted the lux to lumens at 12" away and it's 47,566 lumens covering 8ft2 and at 18" it's 31884 running only 186watts

 

[gk skunky]

I basically use mine just as a guide for light height and angle to try playing with spread over the area for a basic idea. Expensive way of going about it but wanted more than lux.

 

[REALSTYLES]

 

[Abiqua]

No, I haven't. I don't think it's suitable for measuring intensity. Just quality (spectrum). It seems like it would add the SPD required to calculate the parts chopped off by the Apogee PAR meter(?).

I am not comparing it to an Apogee....I also have the Cree bulbs, so it creates a common source for a baseline......I am working on building my own PAR meter......Apogee is in the cards for others, but not me....

 

[az2000]

I am not comparing it to an Apogee....I also have the Cree bulbs, so it creates a common source for a baseline......I am working on building my own PAR meter......Apogee is in the cards for others, but not me....

I understand now. I got confused by part of your post I didn't quote ("That would be interesting to see measured from inside the canopy"). I thought you were talking intensity inside the canopy.

I'll create a graph of a Cree bulb soon. (I did it before but didn't keep it.).

 

[gk skunky]

I am not comparing it to an Apogee....I also have the Cree bulbs, so it creates a common source for a baseline......I am working on building my own PAR meter......Apogee is in the cards for others, but not me....

Are you doing ground up or going off previous DIY lux to par meters using layered filters? Thought about DIY. But wanted a calibrated standardized unit versus getting the quartz setup and other equipment to do myself.

How will you be calibrating your sensor to normalize your data?

 

[the dopest]

REALSTYLES, I have a cheap LUX meter as well, can you tell me how you converted the LUX to LUMENs? I tried an online calculator but it came out 713 Lumens at 8" from a CXA3070 on 1500ma, which I HIGHLY doubt it correct.

 

[REALSTYLES]

REALSTYLES, I have a cheap LUX meter as well, can you tell me how you converted the LUX to LUMENs? I tried an online calculator but it came out 713 Lumens at 8" from a CXA3070 on 1500ma, which I HIGHLY doubt it correct.

lumens = 0.09290304×lux × (square feet)
or
lm = 0.09290304×lx × ft2

I took the readings from different heights from the center of the light. More test will come.