light mover

[davejnz]

I have always wanted to rig up a light mover for my MH.It would help my tank considerably because i only use 1 MH.It would really only need to move 3 times a day.Has anyone ever built one?Got any links or ideas on how to do this?

[dakar]

You mean like moving a pendant type fixture up and down over the tank? Assuming you'd want it to be automated too?

[davejnz]

Yes,say starting at the left side of tank for 3hrs,then moving to middle for 3,then moving to right side.It would be nice to have it automated.

[davejnz]

I really think it would help corals grow in all directoins rather than towards the light.Kinda like the sun moving across the sky.

[davejnz]

basically,rig the reflector/bulb up to a track.Figure out a way to move it on the track with motors that were timed and geared to move the bulb a certain distance.I could always re-set the reflector/bulb at the end of light cycle back to the "dawn"setting by hand .I got the idea,just need some of the technical know-how to get it done.I'm good with electronics/wiring and carpentry/metalworking but engineering it and making it functional w/motors/gearing/timers/ is where i need help.

[dakar]

Kinda thinking out out, but how about just rotating the fixture itself (picture a a central axis above the fixture) would accomplish the same thing? I'd think that would be pretty easy to accomplish with a little thought, a 1-3 rpm motor and some sort of timer. Maybe getting a couple or more passes a day would be even better?

Or something more elaborate, and proably less pretty to look at like the old closelines with pulley's used at each end might work, a little light gearing, again a 1-3 rpm DC motor should be able to do that, might need some more electronics though for positioning, locator switches and stuff.

[davejnz]

The only prob with that is that i use a perpindicular reflector on a narrow(12.5") tank.By rotating it on a central axis i would be distributing alot of the light out of the front and back glass due to the reflection charecteristics of the perpindicular parabolic reflector.For this to be effective in my tank,I need it to move left to right.Thanks for your ideas,If you could assist me(esp. with the motor/gearing/timing)in this project please PM me.If I cant get this accomplished,I'll have to get another halide which i really dont need with a mover in use.

[davejnz]

I've heard of light movers being made and used efectively(mostly on huge growout systems) just never seen one in action.IMO,they are a great idea because they would create a more natural environment.the light would be hitting the corals at all sides instead of just uni-directional.It would save money/energy by not having to add another Mh to avoid "shadowing".Would stop uni-directional growth.

[Reef_Angel]

Interesting idea Davejnz. :) It would mimic a days normal cycle a little more closely. Did you read something about this or what brought on this brain child? it would insure that all sides of your corals would get light, not just the direct tops receiveing the main amount. :)

[dakar]

Didn't think it thru ehough, rotating the fixture would really not do anything more than throw shadows, regardless of the orientation to the tank :( unless you used mirrors to actually bring the light down.

Maybe a better way would be to suspend it on a track and use a stepper motor to drive it back and forth, how much travel distance are you looking at for a complete pass (tank length minus fixture length)? How long of a photo period? Trying to get the majority of the variables together, I have a guy at the office who's pretty smart about steppers and stuff like this, I can pick his brain a bit Monday and see what he can come up with. Biggest factors I can see right off would be how much load could be moved to the bearing surface to be taken off the motor, then a failproof way to may sure the pendant changes directions when needed. I could invent a computer controlled way to do it using the parallel port, but adding that and a stepper motor and controller will start getting expensive quickly, but he's probably got a much simpler method using something that already exists, I tend to complicate things unessarily.

[davejnz]

I cant take credit for this idea,its been done before Reef Angel.
Well,my tank is 36".The center of reflector/light would start 12" from the left side of tank.It would burn 3hrs then move 6" to center of tank,3hrs later it would move 6" more to he right side of tank about 12" from the right glass. so about 12" total moving distance in 6" increments.Photoperiod would be 9hrs.

[dakar]

Okay let me do some brain picking and we'll see what can with for ideas.

[davejnz]

thanks alot,I knew you would have some good ideas as you are quite the DIY man

[FEEDERFISH]

Threaded rod and stepper motors not sure how to rig it all up, i would have to see the set up but good luck, looks to be some pretty custom work and design ahead

[Whoyah]

I envision something like a scaled down, slow speed worm drive garage door opener. The motor would not half to be very big. Let me think about this. I am big DIY kind of guy.

[jerryc]

The only problem i can c with it is ever thing i can thank of or have used
over the years is to big to look good if looks or a concern.
But their may be some Small drive box's out their that i haven't seen

[dakar]

Gonna bring that back up to the top now... Got some pretty good info from a fella at the office, we sorta mashed our heads together and threw this idea around considering both costs and ease of the build. Here is what we came up with;

Suspend the fixture on a slotted track above the tank, use something like rollerblade/skateboard wheels (these are actually great bearings) to transfer as much weight as possible to the bearing surface of the track.

Some sort of failsafe may be wanted to prevent disaster of the light falling and all the smoke falling out of the fixture and your critters, I think a slotted track with wheels on each side for balance would be the better idea here.

Attaching a threaded rod to a DC powered low RPM motor, pretty easy to find complete with reduction gearboxes and stuff. Using a nut (or two) with floats on the rod (compensates for any flexing of the rod and reduces wear dramatically) attaching the fixture to the float(s). Floats can be made from 1/4" acrylic or whatever is easily available. Add a little white litium grease and viola, you now have a light mover.

From there its either a litle bit of math or a some trial and error with a digital timer to activate the motor. Either let it move continuously through the photo period if the gearing/threading is close enough, or use the timer to control the amount of movement for specific times.

A simple flip/flop curcuit (again pretty simple) will enable you to bright the fixture back to the starting side by reversing the polarity to motor switches to determine when it at each location, or make it simpler; just start from the ending side the following day, circuit flips at lets say midnight, so today the sun rises in the east, tommorrow it rises in the west,etc.....

Make sense? Actually wouldn't be a large operation and not an eyesore. Stepper motors and controllers add too much programming and junk that you really don't need, pretty simple, light on, go that way, light off, light on go this way, light off. Continue looping till the next hurricane screws up the electric again and reset the timers.

[Grandmaster_Toad]

Here is another DIY way.

The light fixture rides in a track on top of the tank or in the hood. Simple Spring and pulley system attached to a mid point on the fixture. THe motor can be attached to a timer. Shouldnt be a big deal at all. If you post some pics and measurements of what you want to use I can try and CAD something up for ya. Mulitple ideas and designs make for good project outcomes....heh heh
GT

[dakar]

Definitely lots of ways to do this, even considered a large lobed cam with a spring return, but think that would not be very aesthetically pleasing and take even more gear reductions.

Anyone else got a nickels worth to throw into the mix? I think the only real requirement is the least number of moving parts the better, easier to build and less points of failure,

[Grandmaster_Toad]

I agree with Dakar...the less moving parts, the less chance for failure. SO ... even the threaded rod/ worm gear would be good. Only one moving part. Again, if you post some pics or meaurments.....Im sure between all of us we can rig something very cool.
GT

[davejnz]

great ideas everyone,my Dad is coming by this weekend and we're gonna try and make a prototype.I'll post back when we get it working

[Proost]

Hello everyone-

I know this topic may be on dieing, but I am new here.

I had the same idea a few years back when a friend wanted to make a 3'x10+' grow out indoor "pond" to grow aquatic plants out for sale to the LFS's. These "light movers" are made for the indoor horticulture industry. The tracks are usually 6+' feet long, but if I remember it looks like they could be shortened. They are just a thin track that a motor runs on from end to end, switching on each end. You could then just have a cycle timer than say turned the motor on for a couple seconds every hour and it would move a little each time, simulating the suns movement. Then at night when the lights are off you could have it cycle back over to the morning side.

Or if you could handle the movement, just have it run constantly all day. If corals are like plants, shorter bursts of very intense light can be beneficial for faster growth.

Here is a link to the light mover I looked at:
http://www.elights.com/linrailligmo.html

[Reef_Angel]

Welcome aboard Proost! This topic is by no means dead. My husband Dakar is still in the midst of making this happen for our tank. We feel strongly that this would be beneficial for our corals. I'm sure he'll be online later in the day today. He's suffering a migraine that has put him to bed which is a rarity, so I'll let him sleep as much as possible through this day! Our grand daughter is visiting this whole week, and 2 yr olds and migraines really don't go very well together I guess. :lol: Anyway, he has many ideas on this subject to share as well and is looking for input too. I see this becoming a very useful thread!! I hope you enjoy the site Proost!