Light mover simulation

[Teag]

Could LED's be dimmed in a pattern that would simulate a light mover? Know if anyone has ever tried? Good idea?
The idea behind a light mover is you can move lights closer without burning them = more PAR, less heat.

 

[sethimus]

lolwut?

 

[Greengenes707]

Could LED's be dimmed in a pattern that would simulate a light mover? Know if anyone has ever tried? Good idea?
The idea behind a light mover is you can move lights closer without burning them = more PAR, less heat.

Can it be done...YES
Will it give the same results...NO. Not a good idea.

The purpose of a light mover, specially with LEDs, is to distribute light over a greater area to even out a whole canopies light intake. Like a robinhood of sorts...steal from the overly rich, and distribute it to the disproportionately poor. The key factor there is the amount of light doesn't change...just how/where it's going does.

On the contrary...by dimming the same amount of leds as were stationary before...you're lowering light output. And for all intents and purposes...no manipulation of PPFD will make up for the lack of total PPF output.

If we wanted that theory to work, we would have to increase the LED count to a point where it is no longer an economically viable solution.
Example...
you want to simulate moving 500w of leds . In order to have a constant 500w on at all times, you might need a system capable of 1500-2000w if they were all on at once. Bringing your cost of production for the lighting system up 4X.
So as one row powers down a new equal row on the opposite of the array turns on simultaneously. and so on.

 

[Teag]

Can it be done...YES
Will it give the same results...NO. Not a good idea.

On the contrary...by dimming the same amount of leds as were stationary before...you're lowering light output. And for all intents and purposes...no manipulation of PPFD will make up for the lack of total PPF output.

I thought with light movers one could get away with a higher PAR albeit for a shorter amount of time. So for my example there are 4 cobs or a strip of LED's lighting a 2' x 4' area. Normally it would be run at 100% at X distance. But by simulating a light mover and moving the lights closer to the canopy the system would never be at %100 due to at least one of the cobs being dimmed. By moving the lights closer the same PPFD can be achieved over the entire space. Although there will be hot spots as the lights dim up and down.

I'm assuming your right and I am wrong, so not trying to argue. I think I'm just missing something.

 

[Teag]

You won't get more ppfd by moving the lights closer, you also wont get the same ppfd by dimming the lights then moving them closer, unless your starting point was too far away and you were losing light to your walls and floor.

Your saying light distance doesn't affect ppfd? So if I put a light on the moon it will measure the same ppfd as if its 20" away?

Below is an excerpt from a company selling light movers.

"Another reason our best LED grow lights should move is we can now get closer. And, that simple change gives us maximum PAR right to the canopy. If our LED grow light were stationary, we would have to keep a distance. That would be an issue because grow light spectrum usefulness diminished geometrically the farther away the grow light system is placed. At just several feet, we might as well have bought the dreadful LED grow lights because we would have turned quality grow lights into bad grow lights. No, let’s not do that. So instead, we can move our grow light systems with LightRail light movers. This way, we get closer and get all that quality LED grow light interaction up close and to more leaf area."


So **IF** a LED on a light mover does provide benefits I guess I don't see why a simulation wouldn't. And it seems like there would be plenty existing setups that this could be applied to.

 

[JavaCo]

You won't get more ppfd by moving the lights closer, you also wont get the same ppfd by dimming the lights then moving them closer, unless your starting point was too far away and you were losing light to your walls and floor.

Are you sure about that ????
https://fluence.science/science/par-ppf-ppfd-dli/

 

[Teag]

You fail to understand.. If you take an led light that is designed to operate at 12" above the canopy and you move it to 1" above the canopy your plants will not get more light OVERALL. Yes PARTS of the plant will get more light, and other parts will get much less.

Ok that makes sense. Although I think using an example of 1" is a bit extreme. I was thinking more like going from 30" to 20".

 

[PSUAGRO.]

difference between ppfd & ppf.....misinformation going on. Happens

Anyone who has used a light mover vs multiple stationary will tell you the general results......more larf and airier tops(again general), but you can impress your internet friends with some epic GPW #s. Ask any grower if they feel ok with saving power at the cost of product density? That should be telling. Cannabis is a high dli plant, design / execute accordingly.

It's all a fine balance till you get it dialed in.....if constantly changing variables? that may be never happen, enjoy

 

[Teag]

Well yeah 1" is a bit extreme.. I was just trying to explain.. What LED are you using?

Ya, although after writing that I realized that a moon comparison was also pretty extreme. I don't have any lights. I've been researching for a little bit and am planning to do a DIY cob or growmau puck build when I can do everything legal.

difference between ppfd & ppf.....misinformation going on. Happens

Anyone who has used a light mover vs multiple stationary will tell you the general results......more larf and airier tops(again general), but you can impress your internet friends with some epic GPW #s. Ask any grower if they feel ok with saving power at the cost of product density? That should be telling. Cannabis is a high dli plant, design / execute accordingly.

It's all a fine balance till you get it dialed in.....if constantly changing variables? that may be never happen, enjoy

Ahh yes, this is more along the lines of my thinking. Didn't know their was a trade off between GPW and quality though. Thanks for the info!

 

[JavaCo]

You won't get more ppfd by moving the lights closer, you also wont get the same ppfd by dimming the lights then moving them closer, unless your starting point was too far away and you were losing light to your walls and floor.

You clearly say you wont get more PPFD if you move lights closer. This simply is not true. PPFD is a measurement at the canopy the closer you move the light the higher the PPFD reading you will get. Now if you said you wont get more PPF then yeah that is correct a light will put out the same PPF at any distance because it is a measurement of the total light output in a spear. anyways check out the link i posted Fluence knows there shit.

Yes I'm sure, like I said previously unless your LED is too far above the plants or I could add is poorly designed and doesn't equally distribute the light. If I have an LED fixture that is putting down a 4x4 footprint at 12" above a 4x4 canopy and I raise it higher than 12" I will now cover a larger footprint and have less ppfd at the canopy. If I go closer I don't end up with more light overall, I end up with hot spots. at 12" I may have had an even 50k lux across the whole canopy, now I hang it at 6" and I have hot spots that might be 80k lux and other parts of the canopy may have only 20k lux.

Now you seem to be correct move the light higher and less PPFD.

 

[sethimus]

You clearly say you wont get more PPFD if you move lights closer. This simply is not true. PPFD is a measurement at the canopy the closer you move the light the higher the PPFD reading you will get. Now if you said you wont get more PPF then yeah that is correct a light will put out the same PPF at any distance because it is a measurement of the total light output in a spear. anyways check out the link i posted Fluence knows there shit. Now you seem to be correct move the light higher and less PPFD.

Think of your light output as a 1 gal of liquid per day, you can sprinkle that over a larger or a smaller area, in the end of the day, you distributed the same amount over the ground, just not as dense...

 

[JavaCo]

PPFD is how much light is hitting the canopy. Unless your light is too high to begin with, as in you are loosing light into your walls and floor, moving it closer is only going to focus the light into hot spots. PPF is the power of the light itself, the goal is to get as much of that PPF hitting your canopy by spacing your lighting/cobs/strips/QB's/ect to give you the most even coverage at a specific height above canopy. Once you've got that ideal height and spacing figured out that's it, you don't move your lights closer, there's no benefit to hot spots and the dimly lit canopy inbetween lights that are too close.

PPFD does care about your reflectors your foot print or anything else besides the ppf hitting the canopy. Once again you are confusing PPF with PPFD. Really man I dont have the time to school you on what PPFD is. I would highly recommend you check out the link live it learn it then you wont be spouting out bad incorrect info in here anymore. Fluence is owned by Osram they produce design and build LED's.

 

[JavaCo]

School me on what PPFD is? LOL really? And then you post information of some overpriced crappy led grow light showing the PAR measurements at the CENTER at different distances? You really have no clue do you?

I like the link you provided that shows what I am talking about. As the light is moved closer to the canopy the center receives more light (hotspots) and the outer canopy suffers from less light, but PPFD (total light of the entire canopy) remains the same.

Dude you must be smoken some good chit, But I don't have time for you. You keep contradicting yourself. One minute PPFD doesn't change when you move the light next post it does then next one after that you are back to it doesn't. Might want to see a good shrink.

 

[Teag]

Below is an excerpt talking about PPFD.
Important point.
-PPFD is a spot measurement at a specific location. (I probably should have used average ppfd in my discussions above)

"
Photosynthetic Photon Flux Density (PPFD)
The second measurement is PPFD which measures the light that actually arrives at the plant or algae. Photosynthetic Photon Flux Density or “PPFD” is a measurement of the amount of light that actually reaches your plants and algae or, as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. PPFD is a ‘spot’ measurement of a specific location on your plant canopy, and it is measured in micromoles per square meter per second. This measurement is expressed by scientists and light engineers as: μmol/m2/s.
"