4 Replies Latest reply on Apr 9, 2015 3:58 AM by PalmerCliff

    Narrowing the detection angle on an ultrasonic sensor


      I want to improve the discrimination of my ultrasonic sensor by restricting the broadcast "spread" of the pulse.  The problem I am trying to solve is detecting too broadly and returning the distance to the closest object only.   I'm thinking of building two cardboard tubes about 2 inches long and with a diameter that just fits over the "barrels" of the emitter and collector.  The inside of these tubes would be coated with polyurethane to absorb most of the emissions or returns from the sides of the tubes.

      There is a slight risk of ignition as polyurethane is flammable, but I don't think there will be adequate heat to create a problem.

      Has anyone tried this, and if so did it (1) effectively narrow the detection angle, (2) explode in flames, (3)melt the sensor, or have other intriguing behavior?

      Can anyone think of something wrong with this idea before I try it?

      Thanks in advance.