Subject:
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Re: Ultrasonic maximum timing
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 16 May 2000 16:29:01 GMT
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Original-From:
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Will Bain <WILLB@SELWAY.avoidspamUMT.EDU>
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Viewed:
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659 times
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Adam Oliver wrote:
>
> Greetings all,
>
> I'm using a homebuilt sonar based on Kam Leang's design, which seems to be
> working quite well. I just have one question with regard to the timing on
> the input port. I'm using the same sonar driver as for the polaroid - right
> now I can't remember which input is used for the return "echo".
>
> My question is, what is the maximum time that the timer can measure before
> returning a -1? I'm curious, as I'd like to know the maximum distance I can
> measure on the HB, so I can set my sonar unit up accordingly.
>
> Thanks for your help
> Adam
I think the register maxes out at 32767. Since it's a 2 MHz processor, this gives:
(32767 cycles) / (2,000,000 cycles/second) = 0.01638 seconds
Up here in the Rocky Mountains, the speed of sound is about one centimeter every 143 half-microseconds, so the maximum range is 2.29 meters.
-- Will
+---------------------------------------------------------+
The big thieves hang the little ones -- Czech proverb
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Message is in Reply To:
 | | Ultrasonic maximum timing
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| Greetings all, I'm using a homebuilt sonar based on Kam Leang's design, which seems to be working quite well. I just have one question with regard to the timing on the input port. I'm using the same sonar driver as for the polaroid - right now I (...) (24 years ago, 16-May-00, to lugnet.robotics.handyboard)
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