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

From: Merle K. Peirce <at258_at_osfn.org>
Date: Tue Apr 6 21:38:43 1999

Oh! magnetic media ABS!

On Tue, 6 Apr 1999, Jason Willgruber wrote:

> 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
> >
>
>

M. K. Peirce
Rhode Island Computer Museum, Inc.
215 Shady Lea Road,
North Kingstown, RI 02852

"Casta est qui nemo rogavit."
              
              - Ovid
Received on Tue Apr 06 1999 - 21:38:43 BST

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