Alt-BEAM Archive
Message #04923
To: beam@sgiblab.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Mon, 28 Jun 1999 14:22:54 +0200 (CEST)
Subject: [alt-beam] Re: Photopopper problems
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On Sun, 27 Jun 1999, Bruce Robinson wrote:
---8<---
> Starting from scratch, with a solar powered 'bot I would most definitely
> consider some form of direct drive. Only if that proved difficult would
> I resort to indirect drive, and I would make every effort to minimize
> friction.
Attached is how an idler wheel reduces rolling resistance.
Compared to the diameter of a pager motor shaft, almost every floor
is somewhat uneven.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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Attachment: idler.gif
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4924 Mon, 28 Jun 1999 10:26:42 -0400 [alt-beam] Suggestion for photodiode substitute... "Beam Mailing List" "Slip" Hey there,
I'll be honest with you in that I'm cheap when it comes to electronics.
If I can redesign a ckt to use another part just so I don't have to buy, it
I will. :-) So when I ran out of photodiodes I got a quick idea-why not use
CdS photoresistors in place of the photodiodes? We're all acustom to seeing
basicly the same photopopper ckt so I'll reference it to the one found at
http://www.beam-online.com/Robots/Circuits/circuits.html
Ok, looking at this
circuit you see the two PD's and that 100K pot. So what if we took the two
PD's out completly. Then place one, say, 50K cds photocell in series with
the *opposite* motor. Resistance is low with a brighter light so if a
brighter light was on the right the cell would go low which would make the
left motor faster. Without actually testing this I can predict the turning
radious would not be as tight, but would this work ok?
-Jamie
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