Subject:
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RE: IR scanner
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 30 Nov 1999 15:25:46 GMT
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Original-From:
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Jim Thomas <jim.thomas@trw.com{AntiSpam}>
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Viewed:
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445 times
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There is the classic Polaroid ultrasonic range finder. I think someone here
was working on one of these or similar for lego? They work on the reflected
signal approach. Now I thought you wanted to do off board triangulation.
You can accomplish that using a omni-directional source on the robot and
three sensors around the room hooked up to your PC. You might need custom
acquisition hardware or else the PC might have a ton of data to wade
through.
JT
> -----Original Message-----
> From: Christian Jacobsen [mailto:xtian@net-collect.com]
> Sent: Tuesday, November 30, 1999 7:18 AM
> To: lego-robotics@crynwr.com
> Subject: Re: IR scanner
>
>
> > > The longer the delay, the farther away the robot is from • the sensor. And
> > > the converse.
>
> > I don't think that light-pulse based distance measurements • will ever be an
> > option for Lego robots. But your idea can be used in
> another context (that
> has
> > been talked about around here).
>
> Duh. I spoke before I thought. Sorry about that.
>
>
> > Namely, using a light beam as a directional beacon. • [snip]
> > There is a sore spot here: the robot will be turning and
> spinning - thus
> the
> > angular position cannot be absolute.
>
> Taking Jim Thomas' suggestion of using ultrasonic sound
> instead of lasers,
> you could install two ultrasonic sound sources on your robot
> to solve the
> angular position problem. Set one source to scan a 180
> degree arc in front
> of the robot, and the other could scan the 180 degrees
> behind. Receivers
> around the room could then tell you which direction the robot
> was pointing.
> The question is, how tightly focused can you keep the sound "beam"?
>
> Heck, you might even be able to measure the Doppler Effect to
> determine
> how/where the robot is moving!
>
> OK...I'll try to think a little more before I speak next time! ;-)
>
> - Christian
>
>
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Message has 2 Replies:
 | | Ultrasonic range finder
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| I'm interested in "ultrasonic range finder" type of sensors. One that can return a rough raw value that can be converted into a distance (from the sensor to an object in front of it) would be great. By rotating it, and coupled with an angle sensor (...) (25 years ago, 30-Nov-99, to lugnet.robotics)
| | | Re: IR scanner
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| Jim Thomas <lego-robotics@crynwr.com> wrote in message news:BFBCB00A4D7BD21...TRW.COM... (...) here (...) reflected (...) How about several (>= 3) light sources in an otherwise dimly lit room, and the robot tracking them with a light sensor mounted (...) (25 years ago, 30-Nov-99, to lugnet.robotics)
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