moving head disco light

[laki101]

YouTube - Moving Head - updated YouTube - Moving head - JB Systems iMove 5S - DJ Mixz
ok I want to make something like this

I have worked out the most of it. I will use a computer power supply , 2 wiper motors (one for the U shape and the secont for the head itself). Now I have 2 major problems to solve so I need your help

1. How to connect the U shape to the base so it has 360 degree turning ability. I was thinking on a ball bearing and a metal pipe to put into the bearing

2. My bigger problem is how to transfer power from the base to the U shape. It has to be 360 degree free to turn so wires are not an option. So I need some brush system but not sure how to make one

 

[Sceadwian]

You need slip rings. You'd have isolated rings that carry the power on one side and spring loaded brushes which contact the rings on the other side, it's pretty simply in theory but construction can be a little complex because the rings have to be isolated. It could be done relativly easily if the main rotation shaft was non conducting, you'd just use brass bushings with wire contact in the inner diameter and form a spring loaded contact for the moving side. Hopefully what I'm describing will make sense, it's very simple. You'll need an absolute bare minimum of two connections, +vcc -vcc you'll need some way to talk to the computer onboard as well which you could do by adding another slip ring, although you'll have noise from the brushes to contend with.

 

[Mr RB]

Put a big cap on the load side of the sliprings, and use a series resistor with the brushes to limit peak currents (or use a current limiter ie a constant current source) that will keep brush noise well under control.

 

[laki101]

and I was thinking on maybe putting more ball bearings and passing current with them

so I take bigger bearings and I insulate the inner end and stabilize the outer and just pass current throw it

 

[Sceadwian]

laki, I thought the same thing and it was discussed last year sometime. The problem with ball bearings is the greese will electrically isolate the bearings, and if they don't the electrical arcing from the constant making and breaking of contact as well as the permanent DC voltage will cause galvanic corrosion to occur in the bearings. The only practical way I've ever seen it done is with slip rings and brushes. Possible close contact bushing made from brass with no lubricant. You could do inductive transfer but slip rings work quiet well if they're designed properly. Just think of the success used in the slip ring/brush system used in every brushed DC motor in existence.

 

[laki101]

ok
then I will make some brass (or some conductive matirial) rings and use brushes that I have from electrical drills and stuff like that