Alt-BEAM Archive
Message #11966
To: beam@sgiblab.sgi.com
From: "Zane Bryan" zipndani@transport.com
Date: Thu, 16 Mar 2000 12:34:52 -0800
Subject: [alt-beam] Re: mini motors
This is something I've wondered about - how do you go about getting old
camera lenses? Where do you go? Who do you ask? Are there camera repair
shops? (I'm not exactly up on the photography scene :-)...
...Regarding the lego chain, if you're looking to go smaller, I'm surprised
you're looking at Tamiya 4x4 parts, as they seem much larger. Using the
smallest lego gearwheels and track, you could make a caterpillar track
(viewed side on) about 9mm total height, 20mm length, which is pretty
small. Admittedly, the tracks work better on the next gearsize up
(remembering my lego childhood :), but it's still smaller than the
footprint of most miniature solar panels. I'm not advocating lego here,
I'm elaborating as I suspect I've misunderstood something. Not that it
really matters. :-)
=====================================================================
Justin,
Typically, I get old cameras from one of the local mom&pop shops here in
town (Longview, WA)...Sure, they send their disposable cameras to the
recycler, but the point-n-shoot type are saved out for me. When folks find
it costs more to repair an older camera than to buy a new one, or the
manufacturer doesn't make the parts anymore (designed obsolescence) they
used to give them back to the customer to dispose of...or the customer would
say, "Keep it...I can't do anything with it." Most of what I get are a
two-motor camera...A larger for winding film (-1/2"x+1" or so) and the other
(for focusing the lens) is about 1/2"L x 3/8"H x 7/16"W...pretty small, with
a gearhead. I'd just ask around at locally owned places and avoid the big
name suppliers...The bigger they are the stingier they are. Some places
develope film and offer limited "send out" repair services...being less
specialized, they might be you best bet.
As for Tamiya, I'm actually more interested in the rollers on the bumper
assemblies than the actual gears. At around 1 cm, I think they might work.
I'm using a pully-style tread system, rather than geared (although, the tiny
lego tread is sounding better all the time). The belt/pully style tread
(rubber belts instead of chain) cuts the width down just a bit. And the
cost, since I'm using plumbing seals as belts, is minimal ($.15 ea. fifteen
cents!!!)
I see your point about the gears-for-wheels idea...I hooked up a basic frame
with motors & gears as wheels...not so efficient. It worked okay on the
floor until it tangled in a dust-bunny and seized up. Thanx for saving me
the headache later.
Since I read about someone (you?) attempting the two-sided bot, I've been
intrigued, but don't have the know-how...mercury switches and such are going
to have to wait until I've built a few basics first...I tried tackeling the
idea once and discovered that my design was flawed in that if it were
up-side-down it would become photophobic. I thought about a "tumbler"
switch to to activate a kick-arm (turbot style) to right the bot, but
couldn't get past the idea of a third motor...It got complicated...to say
the least. A simple gravity switch based loosely on the tactile sensor
design might still be a good idea...I haven't thought it all the way through
though.
What I've come up with is pretty much a bot with a low center of gravity and
a roll-bar...(design pending), but I've been looking at a lot of roll-over
toys. Ah, well...back to the drawing board.
Z
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