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Does Ultrasound echo? — Parallax Forums

Does Ultrasound echo?

MarkCrCoMarkCrCo Posts: 89
edited 2014-09-27 06:29 in General Discussion
I have a robot the uses one ultrasound sensor and to infrared sensors to navigate (he has tactile sensors too in case the others miss something). I didn't go with two ultrasounds because I thought they might interfere with each other, From the looks of this http://grathio.com/2011/08/meet-the-tacit-project-its-sonar-for-the-blind/ that would not be the case.

Comments

  • MarkCrCoMarkCrCo Posts: 89
    edited 2014-09-25 18:32
    By echo I mean in the sense of Hello ...Hello...Hello...Hello. Obviously the sensor itself works because it does echo back once.
  • ercoerco Posts: 20,256
    edited 2014-09-25 23:40
    Sure it does echo, but the ultrasonic pulses dissipate rapidly so you would be unlike to get false triggering from a weak secondary echo. Besides, PING sensors time out in under 20 milliseconds (HC-SRF04 is longer but still times out) so that also helps reduce false triggering.
  • ercoerco Posts: 20,256
    edited 2014-09-27 00:37
    Just saw this 3-sensor project which is pretty cool:
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-09-27 06:29
    I suspect the OP really was concerned with Multipath interference caused by more than one source of echo returning. It certainly is possible.

    Using a multiple ultrasonic array would generally try to avoid this creating a muddle by firing only one sensor at a time and allow for the signal to decay before firing another.

    I suppose one could amuse themselves by firing all the array at the same time and then attempt to interpret the data.
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