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 01:50:37 GMT
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Viewed:
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7167 times
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In lugnet.robotics, Brian Davis wrote:
> 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.
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 forward to buying an NXT soon, it looks like fun!
Ben
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Message is in Reply To:
 | | Re: NXT Ultrasonic sensor
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| (...) 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 (...) (20 years ago, 6-Sep-06, to lugnet.robotics)
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