Newsgroups: comp.robotics
Path: cantaloupe.srv.cs.cmu.edu!nntp.club.cc.cmu.edu!godot.cc.duq.edu!news.duke.edu!eff!news.kei.com!world!isi
From: isi@world.std.com (Intelligent Solutions)
Subject: Re: Slip Rings
Message-ID: <Cwn6Cq.MFs@world.std.com>
Organization: The World Public Access UNIX, Brookline, MA
References: <sengle-2309941703590001@port132.blkbox.com>
Date: Sat, 24 Sep 1994 16:12:26 GMT
Lines: 41

sengle@blkbox.com (Steven W. Engle) writes:

>Greetings. I wish to implement a rotating scanner on my 6.270 robot. It
>will have numerous sensing devices on it. I would like to have it be able
>to rotate continuously through 360 degrees. I'm looking for info on a
>piece of hardware I believe is called a Slip Ring - it is a device which
>allows you to pass electrical signals through a continuously rotating
>joint. It is essential a set of sliding (rotating) electrical contacts.

>Any pointers toward what's available? Do I have to worry about electrical
>noise being introduced due to sliding contacts? The signals I plan to pass
>through it are NTSC video, TTL signals, Polaroid Sonar Sensor signals, B+,
>and ground.

>Steve Engle
>sengle@blkbox.com

>-- 
>--
>Steve Engle
>sengle@blkbox.com

You are right about a slip ring being the device you want to transfer 
signals and or power through a rotary joint but the cost might be way too 
high for your application.  While I was at Denning Mobile Robotics, I 
looked in to slip rings for transferring signals from the rotating head of 
the robot to the body.  The solution we found worked but it cost about 
1000 dollars depending on number of channels and quantity of slip rings 
bought at one time.  The slip rings we found were designed for 
military/aerospace applications so were quality units but expensive.  
Even so we never put low level unbuffered signals thru them.  The ones we 
used were made by Airyflight (spelling?) in New Jersey.

An alternate solution might be limiting the rotation to 500 degrees in 
software and then turning the other way and using microswitches on the 
twisting cable to stop the rotation before the cable breaks when the 
software goes off on its own.

Jim Maddox	Intelligent Solutions Inc.
		The home of EZNav - a position sensor for Robotics.

