Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!mips!pacbell.com!pacbell!ptsfa!dmturne
From: dmturne@PacBell.COM (Dave Turner)
Newsgroups: comp.robotics
Subject: Re: What is the cheapest shaft encoder you know of?
Message-ID: <6185@ptsfa.PacBell.COM>
Date: 18 Jun 91 18:39:40 GMT
References: <966@agcsun.UUCP> <3755@intvax.UUCP>
Reply-To: dmturne@PacBell.COM (Dave Turner)
Organization: Pacific * Bell, San Ramon, CA
Lines: 29

In article <3755@intvax.UUCP> mack@intvax.UUCP (Michael J. McDonald) writes:
>If I were developing a home-brew encoder, I would probably use a
>knotched disk attached to the shaft and a radio-shack quality photo
>transistor/detector pair reading across the gaps. Quad detect would

An article in the July, 1980 Ham Radio magazine told how to make a simple
optical shaft encoder.

The article, "Rotary-dial mechanism for digitally tuned transceivers"
used a photodisk with 50 and 100 marks per revolution. It included circuitry
to detect rotation and direction of rotation. It could be setup for 50,
100 or 200 pulses per revolution.

The photo disk was available for $1.00 from the author. The 50 mark disk
was about 2.5 inches in diameter; the 100 mark disk was 3.5 inches diameter.

A query to an online HAM callbook shows that his address has changed.

Anyone interested in the photodisk (and maybe a copy of the HR article)
might want to write to him (include a SASE) at:

	Chet B. Opal, K3CU
	4900 Timberline Drive
	Austin, TX 78746

He said in his article that he welcomed letters.

-- 
Dave Turner	415/823-2001	{att,bellcore,sun,ames,decwrl}!pacbell!dmturne