Alt-BEAM Archive
Message #11096
To: beam@sgiblab.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Tue, 29 Feb 2000 09:27:23 -0600
Subject: [alt-beam] Re: mini walker
Nope, I'm not using motors. they are solenoids. Simple coils to attract
and repel a magnet mounted to the legs. the legs move VERY freely. The
joint has very little friction. I've proven that the coils from
solarbotics can move the legs (the whole robot infact! :)
Also, how would it be cost effective to buy expensive motors, when I can
spend about $10 or less for making or buying the coils???
> Dane Gardner wrote:
>
> Correct me if I'm wrong Richard...but it seems to me that your just
> trying to make a couple of super high torque motors that are small
> enough to fit on a tiny robot. Wouldn't it be easier, and more than
> likely more cost efficient, to just buy said motors?
>
> Just a thought, not a flame.
>
> Dane Gardner
--
Richard Piotter The Richfiles Robotics & TI web page:
richfile@rconnect.com http://richfiles.calc.org
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11097 Tue, 29 Feb 2000 09:42:58 -0600 [alt-beam] Re: numeric symbol for a .1pf ceramic cap beam@sgiblab.sgi.com Richard Piotter Not avaliable my foot! Even Radio Shack sels them!!!
It's not the most convenient, but I get them out of a "pf Pack"
assortment that Radio Shack has. The upgrade is a ti-81/85/86 upgrade,a
nd when the turbo switch is installed, the wires leading to the switch
and the switch itself are sufficient for the acceleration to work. In
other words I rarely use them anyway. Only time I add the part is if the
display drivers start loosing sync with the input. If that hapens, lines
or garbage appear on the screen. The TI-82/83 are more suseptible to
sync problems. I've had trouble pushing them any further than 12 pf.
usualy 15 pf is all you can go. That's where the pf pack helps. if one
speed doesn't work, you grab the next larger cap and solder it in. Using
basic capacitance formulas, you can add capacitors in parallel witht he
switch so depending on if it's open or closed, you add another capacitor
in series. this allows adjustable speed.
Works great. C9 on the TI-81/85 is the one to be modified. C13 on the TI-86.
I do not remembe rthe capacitor number for the TI-82 or 83. The TI-92
can be upgraded, I think with an 8 pf cap, and the newer calcs, (89, 73,
83 plus, 82 plus, 80) I'm not familiar with.
John Bachman wrote:
>
> I am trying to read between the lines here, so if I am way off base please excuse me. It sounds like you are trying to build a very high frequency clock oscillator and therefore need a very small timing capacitor.
>
> If so, you have a couple of problems. First, the value of 0.1pf is extremely low and probably not available. As I mentioned before, two parallel pc runs or wires can easily have 0.1pf of capacitance between them. Hence any circuit components would be insignificant. Also, the series inductance of wires/pc runs would become a significant factor. You need another approach.
>
> Secondly, a ceramic capacitor is a poor choice for a timing capacitor because of it's wide value tolerance and thermal characteristics. Ceramics are generally used only in decoupling and other applications in which the value is not critical to the circuit function.
>
> With more details I can probably help more.
>
> John
>
> At 06:23 PM 2/25/00 , you wrote:
> >it's for a processor clock
> >
> > |___|
> > -------O()O-------
> >James Taylor
> >URL: http://fly.to/springmeadows
> >----- Original Message -----
> >From: John Bachman
> >To:
> >Sent: Monday, February 28, 2000 4:23 PM
> >Subject: Re: numeric symbol for a .1pf ceramic cap
> >
> >
> > > 0.1pf? That is an extremely low value. The capacitance between two
> >parallel pc runs is in that area. May I ask why you want it?
> > >
> > > John
> > >
> > > At 04:12 PM 2/25/00 , you wrote:
> > > >Does anyone know the numeric symbol for a .1pf ceramic cap. Or knows a
> > > >site where I can look such data up?
> > >
> > >
--
Richard Piotter The Richfiles Robotics & TI web page:
richfile@rconnect.com http://richfiles.calc.org
-- Make Money by Simply Surfing the Net or responding to E-Mail!!!
-- Click below!!!
http://www.alladvantage.com/go.asp?refid=ATL147
http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630
11098 Tue, 29 Feb 2000 11:42:22 -0500 [alt-beam] .....lens motors..... "BEAM Mailing List (E-mail)" "Scolman,Jim" Good morning, with respect to "lens" motors.....some folks have mentioned
cameras, do these motor/gearbox addemblies come from auto focus
cameras?........why "lens" ?........yours in learning......JWS.
Jim Scolman
AMS Services, Inc.
Bothell, WA
425-402-1000 x353
206-910-6095
scolmaji@amsworld.com
Network Administrator
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