Destructive charities (was: STAPLES STORES...)

From: Geoff Roberts <geoffrob_at_stmarks.pp.catholic.edu.au>
Date: Fri Feb 15 22:15:38 2002

----- Original Message -----
From: "R. D. Davis" <rdd_at_rddavis.org>
To: <classiccmp_at_classiccmp.org>
Sent: Saturday, February 16, 2002 12:37 PM
Subject: Re: Destructive charities (was: STAPLES STORES...)


> Quothe Tony Duell, from writings of Sat, Feb 16, 2002 at 12:19:06AM +0000:
> > Incidentally, am I the only person who's raided useful stepper motors
> > from old floppy drives with worn-out heads?
>
> Stepper motors, components, bits of metal, wire, screws, etc. are all
> useful things to be found in such drives.

Indeed. I am in the process of making a pc controlled pan/tilt head for a
webcam using bits gleaned entirely from 5.25" drives.
By using the stepper controller and some of the sensors that already exist
in the disk electronics it can interface directly to a parallel port that I
control with software written in my (classic? must be close.) 'old but good'
Turbo Pascal 6 for DOS.
By judicious use of the drive select lines, it's possible to control several
'drives' from the one port so a pan and tilt plus (say) focus or something
similar is possible. Got plenty of half dead 5" drives, prefer the older
Chinons as they have huskier stepper motors with conventional shafts, the
really small steppers with the worm threaded shafts are harder to
mechanically interface and a bit feeble as well.
I have a really husky one pulled out of a huge old 9pin printer that I'm
saving for an antenna rotator with computer control. I want a 2M antenna to
follow the International Space Station for packet radio purposes. At
14v/700ma per phase, it's a brute. I tried driving it as an alternator with
a slow dc motor and got 44v out of it! 1.8deg per step, so if I half step
it I can get better than 1 degree resolution. Will need to build an
appropriate driver board, it would toast a floppy drive stepper controller.

The development box is a 386sx diskless ultra compact with 8mb of ram which
I have a dozen or more of. (dumpster bound at the school I work at) so they
will be dedicated, one to each web cam. Hope to make each workstation/cam
remotely controllable over an ip network. The software still works under
server based Win3 (95/98 too butnot XP , it runs, but the port gets nothing)
so might even use VNC or similar. This is even on topic as the 386sx
diskless box is 11 years old now. Very nice for playing with dos software
on, netboots off my Novell server, no drives of any kind to bother about.
Very small box, around 14" long, 9" wide and about 3" high. It's sitting on
top of the CRO with the lid off as I am powering the butchered disk drive
from the 60w psu. Powering it from a separate supply creates earth looping
issues that confuse the hell out of the logic by lifting the pulled down
voltage about .4 of a volt, which is just enough to make it look like it's
not a low. Still working on that issue, but if it runs from the driving
pc's supply it works fine. Can also toggle the 300/360rpm spindle motor,
but am yet to figure out a use for it. Windscreen wiper?

Cheers

Geoff in Oz
Received on Fri Feb 15 2002 - 22:15:38 GMT