Subject:
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Re: NXT Ultrasonic sensor
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 6 Sep 2006 01:29:57 GMT
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Viewed:
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2519 times
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In lugnet.robotics, Ben Ventura wrote:
> Can I use [the US sensor] to take a bunch of readings
> and then use them assemble up a 3D picture of what is
> around the sensor...
Well, sort of. First, what the US sensor returns is the range of the nearest
sound-reflecting surface: but it's not a pencil thin laser beam of sound, so the
same object might be detected at slightly different angles, making the object
apeear "wider" than it really is. And if the object is at an angle to the sound,
it might not return enough sound energy to the sensor, resulting in the sensor
seeing nothing, and reporting that area "clear". Finally, it only looks out
along a line, so if you want a 3-D representation, you would have to pan the US
sensor all around, as well as tilting it up and down.
*BUT*, if you're happy with a 2-D representation of what's around a rover that
is spinning in place... well, I've got that done now. I've yet to add
autocalibration code so it only works accurately on my own rover, but
autocalibration code is coming (so that one set of NXT-G code will operate
correctly on slightly different platforms... different wheels, different
wheelbase, different gearing, that sort of thing).
> How long does it take to for it to sample each
> distance reading?
IMS, it takes about 12 ms per "ping" from the sensor.
--
Brian Davis
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Message has 3 Replies:
 | | Re: NXT Ultrasonic sensor
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| (...) PS - the thing I would want the radar to do is to guide a bucket for an excavator. The goal being to dig lego bricks from a pile with the bucket. So I think I can get away with it not being super-accurate or resolute. I'm really looking (...) (18 years ago, 6-Sep-06, to lugnet.robotics)
| | | Re: NXT Ultrasonic sensor
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| Hi, (...) since sound travels at about 333 m/s (depending on temperature and pressure), a meter takes 3 milliseconds. At the maximum range of 2.5 meters, times two that would be 15 milliseconds per reading. Cheers Jürgen (18 years ago, 6-Sep-06, to lugnet.robotics)
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Message is in Reply To:
| | NXT Ultrasonic sensor
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| I haven't bought an NXT yet and I have a question about the ultrasonic sensor it comes with. Can I use it to take a bunch of readings and then use them assemble up a 3D picture of what is around the sensor, kind of like how a radar works? How long (...) (18 years ago, 6-Sep-06, to lugnet.robotics)
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