Alt-BEAM Archive

Message #11151



To: beam@sgiblab.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Tue, 29 Feb 2000 18:41:49 -0600
Subject: [alt-beam] Re: mini walker


Thanks for the sugestions. I'm still not sure what method I'll use. I
have a new idea that'll make it easier to mount the coils and magnets.
shouldn't take much work, but I'll have to reposition the magnets.

The newer design will work better. 2 coils, magnets on either side.
small iron core for retention of the legs. one magnet always is in
contact with the coil. that means that even a small kick can get the leg
moving and then the other magnet is attracted and latches. the coils
will bew mounted dead center between the frame bars, and the magnets
will be mounted on a U bar attached to the legs. With a small iron core
for "stick" it should be much more ideal than my curent solution. What
would be best? I thought of an SE type system with a timed trigger. Is
there a way to create an SE that triggers different pulse outputs in
chain? I'll play with circuits. That's what we're here for anyway. New designs!

I like the new design better. Now to find that little 4th magent that
rolled on the floor! :)


Sathe Dilip wrote:
>
> Richard Piotter wrote:
> >
> > As mentioned earlier, the distance the magnet travels is 1/4 inch.
> >
> > Would it be wiser to use a pair of coils, one on either side of the
> > magnet? If so, what'd be the recomended wiring, series or parallel.
> >
>
> That would certainly help. But if you want try with a single coil
> first. If you find that the force is not enough, add the second one.
> Series or parallel both will work & will have their pluses & minuses.
> Assuming the coils are reasonably identical, connecting them in parallel
> will double the current requirements. You will have to use a fatter
> capacitor & more capable switching devices (transistor/IC). Using them
> in series will make them both carry the same amount of current but
> unless you have a higher voltage to drive them, the individual pull/push
> will be somewhat lower.
>
> I think connecting them in series will also flatten the initial kick due
> to increased series inductance.
>
> Now I have another question. Are you planning on using the sticking
> force between the magnet & core to hold the legs during their idle cycle
> Or planning to use a steady current flowing through the magnets to do
> this/augment this? Your answer will have bearing on the coil design.
> You want little to no load on your source when a leg is not moving =
> high coil resistance = lower kick & holding power. If you design for
> more pull & kick, the steady state current drawn (which is only limited
> by the coil resistance) goes up. If you could make it work with only
> the (passive) sticking force, that would be ideal.
>
> Dilip
> ----------------------------------------------------------------------
> The early bird may get the worm, but the second mouse gets the cheese.
> ----------------------------------------------------------------------

--


Richard Piotter The Richfiles Robotics & TI web page:
richfile@rconnect.com http://richfiles.calc.org

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11152 Tue, 29 Feb 2000 16:12:23 -0800 Re: Diskette Drives/camera parts "Richard Piotter"
> Those oh so great motors are the rectangle motors that are used in some
> slot cars, model trains, and other small toys. I'm not certain if they
> are different internaly, or how efficient they are. I've taken apart a
> couple of those disc cameras.
>
> Timothy Flytch wrote:
> >
> > Has anyone used the motors from disc cameras... I remember a few years
ago
> > when kodak first introduced these cameras there was a lot of write up
about
> > the motors revolutionary size/efficiency... it is this ancient
history???
> >
> > Timothy...
> > ______________________________________________________
> >


11153 Wed, 01 Mar 2000 01:10:59 GMT [alt-beam] Re: Symets with legs beam@sgiblab.sgi.com "Mike Kulesza"
I made a SHOCKbot - basically a motor+SE+3733 cell, on 4 wire legs. The
motor turns an offset weight, causing the bot to shake. The weight of the
bot is so distributed that with each shake, it shifts forwad about 1-2 cm.
I'll have pics up soon.
______________________________________________________



11154 Wed, 01 Mar 2000 01:16:45 GMT [alt-beam] Re: Radio shack solar panels beam@sgiblab.sgi.com "Mike Kulesza"
You could break the cell into 10 pieces, and put them in series to get 100
mA and 4.5 V. Thats real nice. In theory, you would be able to drive a
walker.
______________________________________________________



11155 Tue, 29 Feb 2000 20:23:30 -0500 Re: Hey! What's this thingy? Rob
> You could try the Chip directory email list .
> They just love questions about mysterious chips.
>
>
> Rob
>
>

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