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Subject: 
Re: Ultrasonic sensor interactions
Newsgroups: 
lugnet.robotics
Date: 
Sat, 20 May 2006 03:19:07 GMT
Original-From: 
Tim Rueger <trueger@NOSPAMyahoo.com>
Viewed: 
7274 times
  
On May 19, 2006, at 5:41 PM, John Barnes wrote:

> In lugnet.robotics, Tim Byrne wrote:
> > Can someone from the MDP comment on how multiple robots using the
> > ultrasonic
> > sensor interact.  It is possible to use this sensor reliably when one
> > or more
> > other robots nearby are using theirs?
> 
> 
> In a word, multiple ultrasonic sensors can be a problem. This is a
> general
> problem and not specific to Lego ultrasonic sensors.
> 
> Pulses emitted by "the other sensor" can arrive at just the wrong
> moment,
> creating a false range reading. Clever numerical filtering can
> eliminate this
> kind of thing under certain circumstances - for example you may be
> following
> parallel to a wall and obtaining a series of readings which should be
> all within
> a likely range. If you suddenly receive a reading which is outside the
> expected
> range, you might discard it. In otherwords, if you maintain an average
> and only
> accept readings within a certain range of that average as bona fide,
> then you
> may be able to guard against this kind of interference to a certain
> extent.
> 
> JB

How feasible would it be to set up some sort of
time-sharing communications over Bluetooth to
allocate time slots when each of the robots in an
area would be allowed to use their ultrasonic
sensors?

-Tim



Message has 2 Replies:
  Re: Ultrasonic sensor interactions
 
Hi Tim, (...) it should be possible to use the ultrasonic sensor itself for that, there is a command to listen in on other sensors for that purpose. Jürgen (20 years ago, 20-May-06, to lugnet.robotics)
  Re: Ultrasonic sensor interactions
 
(...) Very feasible... IF you could turn the US sensor off. As near as I can determine, the US sensor, when connected, is never off: it is always emitting a series of "pings" (you can actually hear a "click" from the sensor if you are really close). (...) (20 years ago, 20-May-06, to lugnet.robotics)

Message is in Reply To:
  Re: Ultrasonic sensor interactions
 
(...) In a word, multiple ultrasonic sensors can be a problem. This is a general problem and not specific to Lego ultrasonic sensors. Pulses emitted by "the other sensor" can arrive at just the wrong moment, creating a false range reading. Clever (...) (20 years ago, 19-May-06, to lugnet.robotics)

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