Newsgroups: comp.robotics
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From: quartlow@netcom.com (Len Turnbow)
Subject: Re: Advice on magnetic feet? (climbing a metal wall)
Message-ID: <quartlowCtMu84.Kt7@netcom.com>
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Date: Thu, 28 Jul 1994 04:09:39 GMT
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Pat Niemeyer (pat@sbctri.sbc.com) wrote:

: I want to build a very small robot which can climb a metal wall using
: some kind of magnetic feet.....(Snip)

Pat, are you sure the wall is ferrous?  Tested with a magnet?
I saw the permanent magnet overdrive used once in an audio-visual machine.
It appeared to work fairly well.  I expect that a forward-bias current
must have been used during "attach" time to remediate the demagnetizing
effect caused by reverse-overdrive.  Please consider the additional 
demagnetizing effects of heat.  You can limit heat by using many more turns
of wire on your solenoid feet than might be required normally.  
This higher impedance requires a higher drive voltage, but lower current 
(limiting heatrise).

If you had some cam-actuated suction cups for feet, your 'bot might be able
to walk up any non-porous surface.  (!)

My $ 0.02.   Good luck!

--Len (quartlow@netcom.com)

