Let's Make Robots!

Slip Ring

To support my idea for building a 360 degree range finder, I want to build my own slip ring assembly.

I'm thinking of using a copper clad board to create concentric rings. I found a manufacturer that uses this technique. I posted a picture from them below.

slipringPlatterSeparates_prod_banner_narrow.jpg 

The lower ring provides the brush contacts to maintain contact with the rings as the parts rotate relative to each other.

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I'm a couple years late on this, but did you use this slip ring or something else like fritz's audio jack?

this is the same problem faced by wind turbines.  I think they use concentric collars, or similar.

depending on your application, it needs to be load-baring also.

I'm working on something similar right now, but only for power, not data.

Nah, I never put this one into practice. Maybe someday.

Didn't fritsl use a audio jack for just the same purpose here: http://letsmakerobots.com/node/1400

 

You are right. I'd looked at this before, but I hadn't seen the detail on the 2nd video about how he used the audio jack. I was having a lot of trouble visualizing it, because I didn't understand how you could pass signals up the stepper motor axle into the moving component.

The answer is: you don't.  You just bring in the signals from the top and let the motor spin the unit separately. It made sense as soon as I saw it.  Thanks for reminding me of this.

Yet another great solution by Fritsl.

There are 2 other possibilites for sources of slip rings.

 The cheap toys spinning wands generally have a slip wign for power and grpund boing to the LED display.

VCR heads have a vert=y nice multichannel slip rings, little large but high quality.

 Myc 

Good tips. I've thought of both, but haven't really dug into it. Actually I have two of those little kid's spinning LED toys that I already pulled the motors out of for my mousebot.  I'll could canibalize some parts from there or try adapting the whole mechanism. I'll give that a try before making my own.

I'd read the VCR heads had high quality rings.  I should go find a dead one somewhere. Lots of other good robot parts in there anyway.

Honeybee Robotics produced a roller slip ring that has much reduced noise. Might be possible to duplicate if you have a lathe.

That looks a bit sophisticated for me to reproduce at hone. Very cool technology, though!

Despite the high probability that my DIY slip ring will make a lot of elecrical noise, I'm going to give it a try. Parts are cheap enough, so I'll consider it a challenge to myself. I won't even have the advantage of using gold contacts or anything fancy like some of the commercial models do.

It it doesn't work for signals, I can always use it later for power transfer or some kind of rotating LED display.

 

I'm with KL on this, noise up the yang. Not sure if using caps would help to smooth the signal, but it's a thought.

You could use a mini wireless link and use a dedicated chip for the sonar and just use the ring for power as opposed to sig and power.

Caps would be fine for the power lines, or slow signals, but I suspect that any cap large enough to smooth out the contact noise would also be large enough to degrade any reasonable speed communication lines.