DIY light mover?

I'm playing around with the design of a DIY light mover right now that wont require 2 motors able to freespin when off, nor a gearbox to make it go 'the other way'..

What I've came up with so far is to put the light on a rail seperate from the motor/drive system..
Then, make a drive system with something like a bike chain & sprockets, with 1 side having the motor and the other side for support..

I plan on mounting something to the chains that will connect the 2 together, (like a rod able to rotate with a gap in the middle to go around the pole the light's hanging from)..
Something in the shape of:
o-[ ]-o <-- where the o's are where it can spin freely and the [ ] is where whatever the light's hanging from goes inbetween..

Once the connector goes over one edge or the other of the rotating chain, it will simply move the light back the other way..
This will also give some hangtime on the edges where people seem to like it, and the sprockets can be adjusted from big (to allow more hang time on edges) to small to allow less.

I'm not an artist and this is hard to describe but here's a quick sketch.. any improvements/ideas/anything you come up with please post it =)
Thanks

I don't quite follow how it would work yet, but I like the basic idea. I'm thinking about building a light mover to put into a cabinet, and travel 48" back and forth over the cabinet contents.

I don't quite follow either. The light is supported in a slotted track to allow back and forth movement and then connected to a bike chain that runs the length of the room? Wouldn't the connector flopping to the bottom pull the light lower?

clever but the chain would have to be very tight otherwise the weight of the light will pull it down & interfere w/ the lower chain when on the top side.

Imagine like this if you don't follow:
A light is mounted with a rope, chain, or pole (steel cables would work best)
So for this example let's say 2 steel cables, and the light is mounted the long ways between the chains (perpendicular to the chains) with the 2 cables going between the 2 chains, say 1 cable 4 inches away from 1 chain, and 1 cable 4 inches away from the other chain. There would be a steel rod connecting between the two chains with two holes in it that the cables would go through. This rod would(must) be allowed to spin where it connects to each chain.
Even though the rod will lower/raise, it will slide up and down the cables that the pole is mounted to.

The only hard part about this design is getting the 2 chains to spin at the same speed instead of the chain with the motor. You can't connect 2 sprockets in the picture via an axle because it will get in the way of the chains holding the light.

One solution is to make another 2 sprockets, connected to an axle of equal length as the 2 sprockets in the picture are spaced apart on either side.. (imagine a car axle w/ 2 tires on it) and push this with a spring, or mount really hard somehow against either (left or right) of the pic. I'm pretty sure I can gear something up where 1 motor spins an axle with 2 gears (1 on each side) that spin the 2 chains in the system pictured.. which will be good in case I need to change the gearing ratio to make it faster or slower..

Another option is to use two motors. I'm thinking this will be easier, but I still don't have any ideas for parts on this yet.

Since I'm going to suspend a cool tube (very light) via cables, I'm figuring some kind of tracks that will support like 2x the weight of the light each.

But for the motor I haven't got a clue about how to make a motor turn at a constant rpm, I know you can use controllers to speed it up/slow it down, but I don't know how to find one that has good torque and slow speed, you know what I mean?
Any ideas on this? We should make a thread of this because I'm def gonna try to do it so I'll put some $ in it and take pics..

So if I understand correctly your design calls for both chain and sprockets to support the fixture, with only one side of the chain driving?

Personally I think that leaves a lot of room for potential issues. I think if you were to have some kind of rail to support the weight of the fixture, and a single chain, with a special link that connects to the fixture which in turn would carry the carrage/fixture up and down the track you might be onto something.

Another issue with using the chain to support the fixture is that you would not have a consistent height from your plants.

Sounds good you'll tweak and modify it as you go! Try to find the simple elegant way, less stuff to go wrong