I built several light movers, all with the same purpose; to get as much growth out of one high powered lamp as possible.
Mine were built from old 10 speed mountain bikes and used the gear reduction. They were driven by junkyard windshield wiper assemblies mounted to drive the back tire backwards. The assembly was powered by a 12V battery charger on low power. It plugged into the same light time the lamp was.
No slip rings needed, the light hung from a swivel that kept it from twisting up the cord. The fixture was a horizontal parabolic wing (yes, one version did indeed use the famous "grow wing") and it was mounted only a foot above the canopy.
The grow was arranged in a circle about 7' diameter with mylar reflective material hung vertically all the way around.
The lamp itself was on a crossbar hanging from the crank ATM of the bike. One end had the light, the other carried a counterweight.
The light itself was mounted about 30" from the center and the gearing was such that it took about 3 1/2 minutes to complete one revolution.
And yes, it worked! Here's why I think it was effective; it turns out that cannabis, like many plants, can "charge up" on bright light and keep its photosynthetic processes going for about 3 minutes or so afterwards. The light never got far enough away to make the plants think it was dark; between the wing reflector and the mylar, everything got light all the time, even if it wasn't the optimal amount.
So the 1000W HPS lamp was so close to the canopy that if the rotator ever stopped, it would fry the tops. Since it moved, the top buds never cooked but they got very strong, if intermittent light from all sides as the lamp passed overhead.
This way the plants all got really strong light but that same light was spread across the canopy, which was itself carefully managed by topping the plants and tying the branches down to spread them out into a flattop shape, a form of ScrOG only without a trellis net or panel.
I ran a dozen plants; 6 each in early bloom and 6 in late bloom, and swapped them about every 3 weeks since the strain I had finished in 6 weeks. Of course this meant I needed a perpetual veg to feed this setup with half a dozen bloom ready plants every 3 weeks, a process done with 4' T12 shop lights in a separate space.
I pulled about a pound and a half every 3 weeks. Not too fuckin' shabby for an old mountain bike, some car parts and a single thouie! Oh, more more detail; this setup pulled that weight even from an HPS lamp that was 4 years old because I didn't know they deteriorated!
Thanks for the trip down memory lane! Somewhere, I still have pics of the rotator, I'll have to find them.
Long story short; get LED, spread them evenly over the canopy and you're way ahead of any silly ideas about moving lights.
