Subject:
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RE: Sonar Recentering Question
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 23 Mar 1999 01:35:04 GMT
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Original-From:
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rmtmd <RMTMD@nospamCONCENTRIC.NET>
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Viewed:
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937 times
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Great idea! Thanks.
Ross Tonkens
Ted Mylenbusch
> Just a suggestion but you could mount a Hall effect sensor somewhere near a
> rotating rounded part on the cage and glue a small piece of magnet to the
> rounded part. You could look for the pulse on a digital input. This way it
> would not add much weight.
>
> Alternatively, you could replace your motor with an RC servo which is very
> easy to center and whose center pulse width, once determined, could be
> placed in your code.
>
> And lastly, adding only a couple of ounces, you could purchase a linear pot
> (say 50k) and have the motor drive it's shaft also. Place a voltage across
> the outer leads and measure the voltage across the wiper and ground when the
> sonar is centered. Hook it up to an analog port and adjust that way. I
> always flatten the wiper stop so it can rotate 360 degrees.
>
> Hope these ideas help.
>
> Ted Mylenbusch
> amylen@worldnet.att.net
>
>
> > -----Original Message-----
> > From: rmtmd [mailto:rmtmd@concentric.net]
> > Sent: Monday, March 22, 1999 1:25 PM
> > To: handyboard@media.mit.edu
> > Subject: Sonar Recentering Question
> >
> >
> > I've rigged up a rotating cage holding the Polaroid 6500 transducer at
> > the front of one of my bots. Every time I turn on the handy board, I'd
> > like the software to begin by centering the transducer facing forward.
> >
> > I've rigged a micro motor to a bevel gear to drive the rotating sonar.
> > The motor's axle passes through the Lego angle sensor. The problem is
> > that whenever the handy board is switched off, lego3_counts is reset to
> > 0, even if the sonar transducer is not facing directly forward.
> > Persistent globals won't help, since they, too, are reinitialized when
> > the handy board is switched on or the code is reloaded.
> >
> > My bot is heavy enough already. I'm loathe to add mechanical limit
> > sensors to what is already a kludgy first attempt to get the whole thing
> > working.
> >
> > Any thoughts?
> >
> >
> >
> > Ross M. Tonkens, M.D.
> > Medical Director
> > Primary Care of Nevada
> > 100 North Green Valley Parkway
> > Suite 240
> > Henderson, NV 89014
> >
> > 702 914-7120 VOICE
> > 702 914-7129 FAX
>
>
>
RMT
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