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theatrus
08/10/2016, 01:46 AM
I've seen a few lighting system (very very rare) which move in order to "track the sun" so to say. They consisted of moving an MH pendant on rails throughout the photoperiod to simulate different sun angles. They were pretty custom, and I don't have any links handy to those.

Now that LEDs are prevalent, and the LED emitters + active cooled heatsink is relatively small and lightweight, what if we build a better version for LEDs?

One idea I had was to mount a directional LED fixture (lens or reflector) on a heatsink, and move multiple units in a wide arc throughout the day.

Here is a very rough 3d mockup of one idea I had:

http://theatr.us/images/sled-led/sled.png

The bottom of the arc could be a geared rack, and the wheels could be axles with pinion gears on them. A stepper motor would drive the "cart" (the box) which is the heatsink, LED, driver(s) and stepper motor, assuming the mass was low enough in the heatsink and stepper assembly, over a 12 hour period.

A more flexible variant with two drive motors could be done where the LED heatsink assembly can rotate on its center of mass and move linearly on rails.

This is really more geeking out about potential ideas. The shadow shifting in the tank could be pretty dramatic with the right setup.

Gorgok
08/10/2016, 03:21 AM
I think having it just run on the track and a cable/pulley setup would simpler than a gear drive.

mcgyvr
08/10/2016, 06:30 AM
Light movers aren't to track the sun.. They are to allow fewer fixtures to cover a larger area..
Used all the time in indoor gardening :) ,etc...
1 light can cover an area that 2-3 would..

But yes.. You could move your lights all day long..
Is it going to provide any real benefit as far as "tracking of the sun" is concerned.. I doubt it.. Still a neat/fun project though..

The one potential benefit is to reduce "underside" shading common with LEDs where SPS corals,etc.. don't grow as well on the bottoms or shaded areas..

theatrus
08/10/2016, 09:38 AM
Light movers aren't to track the sun.. They are to allow fewer fixtures to cover a larger area..
Used all the time in indoor gardening :) ,etc...
1 light can cover an area that 2-3 would..

But yes.. You could move your lights all day long..
Is it going to provide any real benefit as far as "tracking of the sun" is concerned.. I doubt it.. Still a neat/fun project though..

The one potential benefit is to reduce "underside" shading common with LEDs where SPS corals,etc.. don't grow as well on the bottoms or shaded areas..

Yeah, I've seen them on greenhouse systems for sure, at a much bigger scale - this was a long time ago so they were moving HPS lamps around :).

If there are any benefits, its as you mentioned to reduce shading or dead-spots in corals. It could also look neat, and break down a lot ;)

theatrus
08/10/2016, 09:39 AM
I think having it just run on the track and a cable/pulley setup would simpler than a gear drive.

Yeah, a belt drive and just a cam/track is an option.

I can cut prototypes into wood and acrylic really easily so cutting the integrated rack isn't a big deal for me, but its not the only way to skin the cat :beachbum:

BigDave
08/10/2016, 10:00 AM
Option two would be to build a LED light that covered the entire aquarium. Make each row individually addressable. Start with the Eastern most row of lights. Turn that one row on and slowly turn each row on until the whole light is on, then slowly turn them off one row at a time. You'd get a sun up, sun track, sun down. No moving parts, all electronics.

theatrus
08/10/2016, 10:34 AM
Option two would be to build a LED light that covered the entire aquarium. Make each row individually addressable. Start with the Eastern most row of lights. Turn that one row on and slowly turn each row on until the whole light is on, then slowly turn them off one row at a time. You'd get a sun up, sun track, sun down. No moving parts, all electronics.

Instead of doing the whole array, I'd suggest mounting a set of LEDs at three angles per "emitter". 3x the LEDs (or say 1.5x-2x for lower PAR out of the sides), no moving parts. The effect would be similar but not the same.

saf1
08/10/2016, 02:45 PM
Not sure what it would buy you other than a fun project and to see that it could be done.

Tie this to a controller then add in geo codes and you can do some pretty geeky things no doubt :) Another tuning point is what I see. We can already adjust and control spectrum, intensity and duration. Moving the fixture up, down, and left to right is just another option. If you have ever seen Beatlejuice, they have that model city with the stars overhead. I think that would be cool and maybe possible with todays LED emitters.

Granted most of our tanks have a small surface area but you might be able to mimic sunrise and set / left and right so corals get a set amount of light per day. Change the geo code to that of your bio type the lighting could be adjusted automatically. Would be fun and neat - but may not be necessary other than the "cool" factor.

BigDave
08/11/2016, 08:13 AM
Not sure what it would buy you other than a fun project and to see that it could be done.

Tie this to a controller then add in geo codes and you can do some pretty geeky things no doubt :) Another tuning point is what I see. We can already adjust and control spectrum, intensity and duration. Moving the fixture up, down, and left to right is just another option. If you have ever seen Beatlejuice, they have that model city with the stars overhead. I think that would be cool and maybe possible with todays LED emitters.

Granted most of our tanks have a small surface area but you might be able to mimic sunrise and set / left and right so corals get a set amount of light per day. Change the geo code to that of your bio type the lighting could be adjusted automatically. Would be fun and neat - but may not be necessary other than the "cool" factor.

If you're going that far, why not program in a random intensity so that some days are more 'overcast' than others...

Then you could have really dark days where you randomly click bright whites on to simulate lightning strikes..

oh and then....

and then...

(scope creep always killed my college projects too :) )

saf1
08/11/2016, 03:55 PM
If you're going that far, why not program in a random intensity so that some days are more 'overcast' than others...

Then you could have really dark days where you randomly click bright whites on to simulate lightning strikes..

oh and then....

and then...

(scope creep always killed my college projects too :) )

Yes, scope creep. You get the idea, but it is cool, fun, and of course a hobby. Funny thing is on my controller it supports location, sun, storms, etc. I sometimes forget I have the cloud simulation running and walk into a dim or darker tank. That or we'll have lights out on movie night then next thing you see are the blues flashing off/on. Cool stuff.