Newsgroups: comp.robotics
Path: brunix!cat.cis.Brown.EDU!agate!usenet.hana.nm.kr!ames!hookup!swrinde!gatech!europa.eng.gtefsd.com!ceylon!sundog.tiac.net!news.sprintlink.net!dg-rtp!webo!kitkat!pmalenfa
From: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
Subject: Re: controling servo motors
Sender: usenet@us.dg.com (Usenet Administration)
Message-ID: <1994May27.154126.4278@us.dg.com>
Date: Fri, 27 May 94 15:41:26 GMT
Reply-To: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
References:  <2s3ukv$h6e@lastactionhero.rs.itd.umich.edu>
Organization: Data General Corporation, Westboro, MA
Keywords: servo 6811
Lines: 21

In article <2s3ukv$h6e@lastactionhero.rs.itd.umich.edu>, ocg@cw-u02.umd.umich.edu (John Roldan) writes:
|> Hi all,
|> 
|> I bought a $20 servo motor at my local hobby store and am trying to 
|> control it with a 6811.  I am sending a 50% duty cycle square wave down 
|> the yellow wire and am supplying 5v on red and blac.  At various 
|> frequencies all under 30 hz   all the motor does is move to the extreme 
|> right and jitter or just jitter.   So my questions are:
|> 
|> How do you control these things?  vary the frequency ?  or settle on the 
|> frequency and vary the duty cycle?  

You control them by issuing a pulse every 20ms and varying the duty cycle.
There is some particular pulse length that corresponds to "center".
For mine, it was a pulse of length 1.5ms for center, .75ms for left
and 2.25 ms for right.

-- 

Paul Malenfant
pmalenfa @ kitkat.webo.dg.com (508-898-7153)
