New DIY LED light

[wietefras]

I previously said what I would do, his test setup is inappropriate

Of course a test where you try to do what people actually do in reality is something you would feel is inappropriate. Better continue working from middle school experiments instead of facing the fact that you were utterly wrong.

Get back to us when you actually were able to produce a fixture and do the test properly. Or better yet, just get and stay lost with your bullshit. You haven't advance at all since you were using your NoFuckingClue alias a while ago.

 

[GrowLightResearch]

Get back to us when you actually were able to produce a fixture and do the test properly.

As previously stated I may do that. I should have been easier for you to explain all your claims. You have the app you wrote. Just explain how reflection cancels ISL.

Of course a test where you try to do what people actually do

I personally have written much more complete piece of software to do this type of analysis which does include reflectivity.

Okay let's split the work load. You do the calculations with the equations from your app with the 400 LEDs when you show the calculations for each LED, if your calculations do not support what I have been saying, I will buy the strips necessary and run the experiment to whatever parameters that were set by @nfhiggs

Your measurements quite clearly show that inverse square does not apply to the distance of the fixture to the plant canopy.

While we are still on this topic. Please explain why ISL worked for GG when lowering his fixture from 24" to 20" with only 8.2% error.

 

[SSGrower]

@nfhiggs how are your plants doing?

I too would like to know the answer to this as they seem to have been lost in the weeds......

the arguments here are entertaining but do miss several points about actual production capabilities and reasons why things are the way they are and to be honest I used to think measuring down to the gnats ass was necessary, laws of physics are followed regardless of what any of these individual meters read end of argument. Values obtained are only as relevant as any claims for grams/watt, or any other statistically insignificant metric.

 

[GrowLightResearch]

Values obtained are only as relevant as any claims for grams/watt, or any other statistically insignificant metric.

I totally agree. Two things. In many pics on this site I believe based on my research show the fixture being too high over the canopy. I am working on the design of a very inexpensive PAR meter / spectrometer so anyone can measure the PPFD when setting the height of the fixture.

I have been working, for the past 16 months, researching every little detail regarding efficiency. Inverse Square being a significant factor. The reason being I have a solar powered grow fixture and originally it was not feasible.

I have found out over the years that all the little things add up and make a significant contribution.

When explaining something I learned in my research, some one comes along here and says ISL does not apply to a grow chamber. I can't dismiss that, even though that someone is mostly a troll but does have some intelligence. But what he says does not agree with my measurements and research. And reflection and overlap, or anything else for that matter, makes very little sense as to why ISL is not a significant factor. I mean like WTF is overlap. It sounds like the inverse square law. He thinks I do not understand how ISL is different in supplemental lighting in a greenhouse vs a grow chamber. But that's the simplest scenario. I found ISL to work pretty much the same in a chamber or a green house. The problem is when the fixture begins getting very close to the canopy the angle of the rays elongate as they get further away from the sensor. So much so there individual distances are too different from the LED centered over the sensor. So different the other LEDs difference in the ratio of D1 and D2 in the ISL equation are completely different. I did some experiments and found a solution using basic right angle trigonometry. Calculation match my measurements within 1%. Now I am being told my experiment was bullshit. It's not,it was done with the oversite from a university research professor, but if I learn something here no mater how doubtful, I'll play along.

For every one using LEDs to grow, ISL is a very important topic if you spend even just $100 a month for electric.

The metric here is photons per watt. Which if improved may improve gram/watt or reduce your cost per gram.

 

[Randomblame]

@nfhiggs how are your plants doing?

+1, LOL!

 

[wietefras]

For every one using LEDs to grow, ISL is a very important topic

No it's not. Uniformity and wall losses are what matters. Especially the wall losses are usually grossly underestimated which causes people to use completely wrong materials to cover their walls. Like white paint or diamond pattern foil.

BTW Stop pretending that you are a researcher. When you first came on this site a few months ago you couldn't even keep lux/lumen and "umoles" apart and now you still show huge lack of understanding. Not just here, but in other threads as well.

 

[GrowLightResearch]

BTW Stop pretending that you are a researcher. When you first came on this site a few months ago you couldn't even keep lux/lumen and "umoles" apart and now you still show huge lack of understanding. Not just here, but in other threads as well.

Let's keep on topic you were wrong then too. You are very transparent with your ad hominem attack. When you attack with ad hominem that means you are losing the debate becasue you are so desperate that you use ad hominem. Not pretending. And not influenced by your insults. I would need to respect you to be offended. Stick to the topic at hand.

Uniformity and wall losses are what matters.

For what it's worth absolutely it's about uniformity. As far as wall loss, wall loss is a good thing, more is better. Reflections off the wall screw up uniformity. But that's all moot because the fixture belongs close enough to the canopy where reflection and wall loss do not exist. Even if I were using a CoB fixture, that cannot be lowered to close due to its uniformity issues, I would still hang black cloth on the walls rather than a reflective surface.

I would like to see the fixture one inch from the canopy like back in the days of Grow Lux bulbs. Put the fixture right on the canopy and adjust the µmols to the maximum level allowable at that height. The problem is measuring PPFD at under 12". And I got that covered.

 

[wietefras]

Let's keep on topic you were wrong then too. You are very transparent with your ad hominem attack.

It's not an ad hominem attack. You SAY you are a researcher and you are clearly NOT. I'm simply asking you to stop lying.

I would like to see the fixture one inch from the canopy

In practice no one wants that, because it's hugely annoying to have it so close.

Besides in the one thread you claim we should run the cobs/leds harder than we do, but if you do that the light needs to hang higher to get good uniformity.

The problem is measuring PPFD at under 12".

Bullshit again. You don't need to measure PPFD. Just divide PPF by surface area. Geez you even don't understand that? Seriously, stop pretending you are a researcher.

 

[nfhiggs]

@nfhiggs how are your plants doing?

Just harvested my manifold/mainline trained plant. Looks like a bit over 9 ounces, but I probably lost at least an ounce or more to bud rot. Humidity was killing me all during November. Should have another plant in there in 2-3 weeks.

 

[nfhiggs]

I too would like to know the answer to this as they seem to have been lost in the weeds......

the arguments here are entertaining but do miss several points about actual production capabilities and reasons why things are the way they are and to be honest I used to think measuring down to the gnats ass was necessary, laws of physics are followed regardless of what any of these individual meters read end of argument. Values obtained are only as relevant as any claims for grams/watt, or any other statistically insignificant metric.

Here is the last shot I took of her on Dec 3:
https://imgur.com/s7R7bg7

 

[1212ham]

As far as wall loss, wall loss is a good thing, more is better. I would still hang black cloth on the walls rather than a reflective surface.

That'll be efficient.

 

[nfhiggs]

That'll be efficient.

LOL - for growing Basil...

 

[ttystikk]

Just harvested my manifold/mainline trained plant. Looks like a bit over 9 ounces, but I probably lost at least an ounce or more to bud rot. Humidity was killing me all during November. Should have another plant in there in 2-3 weeks.

Good pull! The quality looks good, too.

I've found that more air movement past and through the plant does a good job of minimising bud rot issues, even in high humidity situations. Perhaps a small oscillating fan underneath the canopy would help? It's also supposed to help transport available CO2 to the leaves.

 

[nfhiggs]

Good pull! The quality looks good, too.

I've found that more air movement past and through the plant does a good job of minimising bud rot issues, even in high humidity situations. Perhaps a small oscillating fan underneath the canopy would help? It's also supposed to help transport available CO2 to the leaves.

Yeah, I been meaning to pick up a small fan. Just haven't gotten around to it.

 

[Randomblame]

Here is the last shot I took of her on Dec 3:
https://imgur.com/s7R7bg7

I have a small 2,5gal / 24h dehumidifier especially for this time. Only 89$ and works great for a 16m² basement room and I can keep my humidy below 50% also on rainy days.

 

[GrowLightResearch]

Bullshit again.

 

[GrowLightResearch]

While we are still on this topic. Please explain why ISL worked for GG when lowering his fixture from 24" to 20" with only 8.2% error

You still have not responded to why GG's measurements from 24" to 20" were fairly accurate. Well, other than to say it was a mistake.

Or are you still standing by it was a fluke measurement?

 

[GrowLightResearch]

So.... we are to believe that because its not a cosine sensor that its somehow going to give readings on the order of ten times what your cosine meter would read at that distance (24 inches). Riiiiight.
Two words:
Prove. It.

You have the cosine sensor. 400 diodes. 22" x 22" frame. 10 strips (I'll even donate my two spares). Reflective walls 24" x24". Put up or shut up

It's easy to prove.

Hang a 48" strip at 36". Measure the distance from a sensor to an LED from the sensor to the LED 36" above and 24" to the side of the sensor (on the very end of the strip). Then measure the angle.

Now lower the strip to 12" and measure the distance and angle to the end LED.

While the LED above the sensor distance changed 3x, the end LED changed 1.6x.
ISL 36" to 12" = 9x
ISL 43.3" to 26.8" = 2.6x
Error: 346% (9 ÷ 2.6) x 100
NOTE: This is the same error introduced by the LED on the other end of the strip.



These images are rotated and flipped with respect to one another due to size constraints of the app.




Now take a look at the angle of the photons emitted from the LED. The angles shown for the triangle where the LED is located must be adjusted to the LED's point of view. The 34° angle at 36" becomes 56° and the 27° at 12" becomes 63°. Looking at the Samsung or Bridgelux strip's datasheets the flux is reduced by 60% at 64° and 45% at 56° with respect to the center LED at 0°. So there is another 60% error factor which increases as the height gets lower.


_________________________________________________________
Wrong Tool for the Job

Fist off a lux meter is photometric meaning the radiometric watts are adjusted for humans NOT plants! Furthermore plants do not care about the energy of a photon so the watts need to be conversed by wavelength to quantum moles.

A lux meter must be designed to measure pulsed PWM light which the cheap meter are not. For example, the Konica Minolta T10-A is designed for PWM.

For error rates, an inexpensive Lux Meter is compared to CIE illuminate A which is a tungsten incandescent light source with a CCT of 2756K


From: Colorimetry, 3rd ed., Publication 15:2004, CIE Central Bureau, Vienna

CIE standard illuminant A is intended to represent typical, domestic, tungsten-filament lighting. Its relative spectral power distribution is that of a Planckian radiator at a temperature of approximately 2856 K. CIE standard illuminant A. CIE standard illuminant A should be used in all applications of colorimetry involving the use of incandescent lighting, unless there are specific reasons for using a different illuminant.

​

Was a 2756K strip being measured? So then you must convert every wavelength of the CCT of the strip being measured to a 2756K standard.

Does this look anything like a 4000K spectrum?


More error from the mismatch in spectrum.

As the angles increase the sensors accuracy decreases. Below is the specs from a higher end Lux meter ≈ ($1,000-$2,000)

Notice when the angles get down to the 60°-80°, the error increases from 10-30%. and that is for a high end meter. Notice the 6% error over 3,000lux. But only ±1 digit. Look at the digit error on cheap lux meters.

This chart shows the sharp decrease in accuracy above 60°.

​

A $1,000 lux meter will conform to class A of JIS C1609-1 2006 (e.g. Yokogawa Model 51011: $1,155.00)
A $2,000 conform to class AA of JIS C1609-1 2006 and DIN Class B (e.g. Yokogawa Model 51021: $2,101.00)
Reference: https://www.instrumart.com/products/40519/yokogawa-510-series-lux-meters

 

[GrowLightResearch]

If you really want to see this for yourself, why not build an actual growlight?

More of your "common sense"? Or lack of? You are sounding more and more like the scarecrow rather than the wizard you think you are. BTW I got got a small job Tuesday top assemble a few fixtures for $3,000.




And to your predictable and trite response:

 

[nfhiggs]

It's easy to prove.

You still here? LOL....