Subject:
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Re: !!! Laser attachments for Mindstorms !!!
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 28 Oct 1999 05:49:11 GMT
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Original-From:
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Doug Carlson <dcarlson@net-info.=Spamcake=com>
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Viewed:
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718 times
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alex wetmore wrote:
> On Thu, 28 Oct 1999, Matthew Miller wrote:
> > Kay Neuenhofen <lego-robotics@crynwr.com> wrote:
> > > Yes, plus two touch sensors to implement bumpers. Otherwise, you won't
> > > know when you hit an obstacle. That leads to sensor multiplexing, as
> >
> > Why, if you're keeping track of motion? I mean, if you suddenly stop, it's
> > probably safe to assume you've hit something. :)
>
> In fact the rotation sensors work much better for this, because
> they will easily tell you when you stopped in any direction. It
> is much more complex to build a bumper which surrounds the RCX and
> can detect hits from most any direction.
>
> I did come close to building such a bumper at one point
> (http://phred.org/~alex/lego/wanderer.html was the first version
> of it). My goal was to have a bumper which would detect a
> collision in any direction that the robot would travel. In a room
> full of static objects it could run until the batteries died down,
> but it couldn't deal with a moving obstacle hitting it from the
> side.
>
> alex
The synchro-drive model on my page has a 360 degree bumper consisting of those
rubber bumperpieces used in a Technic Hovercraft some years back. I think they
are presently available on Res-Q
set # 6473 (at least they look the same in the LEGO Shop at Home catalog).
A ring of these is supported by 4 small spring shocks. It uses four touch
switches with contact linkage points
located in the angled corners to detect ring deflection. I added this instead of
relying on the rotation
sensor because the main drive is geared down quite heavily. It's capable of
pushing many items around
instead of stalling the motor. But if something does manage to stop the bot's
motion, the bevel gears closest
to the wheels will tend to slip long before the motor stalls. This was just a
case where it seemed like having
both types of sensors would be helpful. I do intend to use the rotation sensors
for bump detection on my model
of Killough's platform though. All three inputs are tied up with rotation
sensors for motor feedback now so this should be
a great opportunity to try this.
-- Doug
Doug Carlson
dcarlson@net-info.com
http://www.net-info.com/~dcarlson
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Message is in Reply To:
 | | Re: !!! Laser attachments for Mindstorms !!!
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| (...) In fact the rotation sensors work much better for this, because they will easily tell you when you stopped in any direction. It is much more complex to build a bumper which surrounds the RCX and can detect hits from most any direction. I did (...) (25 years ago, 28-Oct-99, to lugnet.robotics)
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