OT: ABS - or is it Pure BS/wheel sensors

From: Jason Willgruber <roblwill_at_usaor.net>
Date: Tue Apr 6 20:12:09 1999

I wonder is it would be possible to devise something that would use some
sort of disc with a bunch of holes in it and the sensors from an old (8"?)
floppy drive?

A desperate attempt to get this somewhat back on topic :)

--
         -Jason Willgruber
       (roblwill_at_usaor.net)
           ICQ#: 1730318
<http://members.tripod.com/general_1>
===============================
---------------Original Message-----
From: Stan Perkins <stan_at_netcom.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Tuesday, April 06, 1999 3:01 PM
Subject: Re: OT: ABS - or is it Pure BS/wheel sensors
>
>It's probably a similar system to the one used by Etak with their early
>car navigation systems. Basically, they used a special adhesive tape
>that contained a small bar magnet every inch along its length. This was
>applied to the circumference of the inside of each front wheel rim, and
>a Hall effect sensor was attached to a point on the front axle (usually
>to a part of the brake caliper assembly) where it was within an inch of
>this tape as it passed by. Each magnet passage would produce a countable
>pulse, and the Etak computer could determine the wheel speed and
>direction of rotation for each front wheel. *Supposedly* it could also
>detect a turn by the differential speed of the front wheels, but it also
>had a flux gate compass to help determine direction and turns.
>
>A pretty clever system that worked quite well, considering it was all
>done without reference to external navigation data sources like GPS,
>LORAN, etc!
>
>Since your system apparently produces only a single pulse per
>revolution, I would guess there's one magnet somewhere on each wheel
>rim. The speed resolution with only a single pulse per revolution is
>probably not good enough for ABS use.
>
>Hope this helps,
>Stan
>

Received on Tue Apr 06 1999 - 20:12:09 BST