Alt-BEAM Archive

Message #08158



To: beam@corp.sgi.com
From: Justin jaf60@student.canterbury.ac.nz
Date: Wed, 08 Dec 1999 17:36:26 +1300
Subject: [alt-beam] Another(?) gearmotor source - useful?


Dick Smith sells motorised pots for NZ$16.95 (US$8.50ish) with trade
discount (or NZ$19.95 without). I think they're pretty much a pre-hacked
servo - just a motor connected to a pot via the gearbox, no circuitry or
plastic case.
http://marketplace.xtra.co.nz/cgi-bin/dse.storefront/108796053/Product/View/R7830
(BTW, as you can't tell from the picture, that's a 16mm or smaller pot
on the front, not a 24mm, so it's not as big as it looks. :)

As these are not "pre-loved" and seem pretty cheap, I thought I'd call
on your expertise (I'm not up with what constitutes a good or bad deal
re gearmotors).
Is it a useful gear speed? It looks like most of the gears are plastic,
is this a big problem?

>Dual Gang Motorised Potentiometer
>Dual ganged 50k ohm log pot in a motorised gear housing.
>Allows both manual and remote control of the carbon film
>based potentiometer making it ideal for volume control
>application. Type: Single Shaft Dual Ganged. Taper:
>Logarithmic. Torque: 100-450 gf.cm. Motor Voltage: 3-6 v
>dc (4.5 nominal). Speed: .10+/-3 sec/300


Dick Smith has been selling these things for years, but just as I take
an interest in them, the website notes that they intend to phase them
out. Still, there are plenty around in the shops, and they often put
things on special when they phase them out...

Comments?

Seeya
Justin



8159 Tue, 7 Dec 1999 23:47:41 EST [alt-beam] Re: 1381L beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 12/7/99 9:04:01 PM Eastern Standard Time,
Blumojo13@aol.com writes:

> So I should run the caps in parallel
> and change to a 1381L?
I'd give it a shot. I'm not sure what your application is, but an L would be
closer, heck you could go with a U even.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



8160 Tue, 7 Dec 1999 23:51:56 EST [alt-beam] Re: new bots beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 12/7/99 9:59:07 PM Eastern Standard Time,
cbrenizer@mail.trib.net writes:

> i had discarded the idea of ever motorizing the rover, not wanting to have
> my homebrew stuff hanging off of it and ruining it's appearance. so hadn't
> even considered using it as a platform for something like a flag waver.
> great idea! and the foil extension looks great too.
Yep, I thought of motorizing the rover as well, but the thing is just to tiny
and there was no way to do it aesthetically. The flag spinner struck me one
night as I was popping head veins over another project. Amazing what a little
diversion can do for one's outlook.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



8161 Tue, 7 Dec 1999 23:54:06 EST [alt-beam] Re: new bots beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 12/7/99 10:37:38 PM Eastern Standard Time,
Sparkyg@seark.net writes:

> looks like you used a fuse clip, right?
Yep, and I used a small cap 3300uF. An even smaller one would work too, say
2200uF. It doesn't take much torque to spin a little flag and a small cap
makes the bugger very active.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



8162 Tue, 7 Dec 1999 21:02:33 -0800 (PST) [alt-beam] Re: new bots beam@sgiblab.sgi.com Darrell Johnson Hey Jim,
Where'd you get that nice PCB for your Unicore bot?




-darrell

great looking bot by the way... it's great how it's
all enclosed.

=====
____________________________________
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8163 Tue, 07 Dec 1999 21:53:47 -0700 [alt-beam] Re: Another(?) gearmotor source - useful? beam@sgiblab.sgi.com Senior Note that they are sold at
http://www.allelectronics.com
For MUCH less! There always seems to be a cheaper source... :) Just
gotta check all the millions of places I guess. But you'll still end up
finding something cheaper after you buy it. Oh well....

Kyle

Justin wrote:
>
> Dick Smith sells motorised pots for NZ$16.95 (US$8.50ish) with trade
> discount (or NZ$19.95 without). I think they're pretty much a pre-hacked
> servo - just a motor connected to a pot via the gearbox, no circuitry or
> plastic case.
> http://marketplace.xtra.co.nz/cgi-bin/dse.storefront/108796053/Product/View/R7830
> (BTW, as you can't tell from the picture, that's a 16mm or smaller pot
> on the front, not a 24mm, so it's not as big as it looks. :)
>
> As these are not "pre-loved" and seem pretty cheap, I thought I'd call
> on your expertise (I'm not up with what constitutes a good or bad deal
> re gearmotors).
> Is it a useful gear speed? It looks like most of the gears are plastic,
> is this a big problem?
>
> >Dual Gang Motorised Potentiometer
> >Dual ganged 50k ohm log pot in a motorised gear housing.
> >Allows both manual and remote control of the carbon film
> >based potentiometer making it ideal for volume control
> >application. Type: Single Shaft Dual Ganged. Taper:
> >Logarithmic. Torque: 100-450 gf.cm. Motor Voltage: 3-6 v
> >dc (4.5 nominal). Speed: .10+/-3 sec/300
>
> Dick Smith has been selling these things for years, but just as I take
> an interest in them, the website notes that they intend to phase them
> out. Still, there are plenty around in the shops, and they often put
> things on special when they phase them out...
>
> Comments?
>
> Seeya
> Justin



8164 Wed, 8 Dec 1999 01:04:56 EST [alt-beam] Re: new bots alt-beam@egroups.com TurtleTek@aol.com JVernonM@aol.com writes:


> http://www.geocities.com/SoHo/Exhibit/8281/rover.html

Woah, I usually don't care much for BEAM ornaments but this is a real
exercise in the "A". Neat desk toy.

> http://www.geocities.com/SoHo/Exhibit/8281/unicore.html

Now that is really dazzling! Beautiful work, beautiful. I like how it's guts
aren't hanging out ( as mines' are ) and the red and black is impressive. The
only thing I don't like is that it isn't solarized. Consider the Choloroplast
maybe?
I was considering building a BEAMant with the CSE but now I'm sure that'll be
my next bot...it'll be all the better having "Unicore" as it's inspiration.

Keep it up, Jim.

-Brien the TurtleTek



8165 Tue, 07 Dec 1999 22:18:16 -0800 [alt-beam] Re: Another(?) gearmotor source - useful? beam@sgiblab.sgi.com Bruce Robinson Justin wrote:
>
> Dick Smith sells motorised pots for NZ$16.95
> (US$8.50ish) with trade discount (or NZ$19.95
> without) ... It looks like most of the gears
> are plastic, is this a big problem?

When designing gearboxes, the power isn't the key design factor -- it's
the torque you have to worry about.

Torque = Power / Speed.

The power stays constant through the gearbox (OK, it actually decreases
due to friction). That means as your gears move slower, the torque they
transmit increases.

Basic principles:

Slowest moving gears have to carry more load.
Narrower gears are subject to more stress.

So wide, plastic gears near the motor are probably OK, as long as you
have metal gears near the output end of the gear train.

Bruce



8166 Wed, 8 Dec 1999 07:32:26 -0500 [alt-beam] Re: new bots "Richard Caudle" Ask your brother.

Richard

Darrell Johnson wrote
> Hey Jim,
> Where'd you get that nice PCB for your Unicore bot?



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