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Paralax sumo bot ir sensor — Parallax Forums

Paralax sumo bot ir sensor

kennylolkennylol Posts: 1
edited 2014-10-27 13:38 in General Discussion
Ok i am working on learning the programing for the paralax sumo bot and i am trying to figure out how to decrease the range of the ir sensors on the sumobot for the fact is they are detecting thing that are much further away than they should how would i do that in code (or any other way if you have any ideas).
Thanks!

Comments

  • ValeTValeT Posts: 308
    edited 2014-10-27 12:48
    The only way I know of is if you change the frequency. Have you tried that already?
  • ercoerco Posts: 20,256
    edited 2014-10-27 13:26
    Good call, Vale T. The center frequency of most IR receiver modules (the 3-pin black gizmo) is 37.5-38 kHz. Your program probably has a PULSOUT n,37500,1 or thereabouts to send the output pulse. To reduce sensitivity, you could change that command to PULSOUT n,39000,1 or 40000 or higher. Or 36000 or lower.

    A simple hardware fix is to increase the value of the series resistor going to the IR LED which sends the 38000 kHz pulse.
  • ValeTValeT Posts: 308
    edited 2014-10-27 13:31
    erco wrote: »
    Good call, Vale T. The center frequency of most IR receiver modules (the 3-pin black gizmo) is 37.5-38 kHz. Your program probably has a PULSOUT n,37500,1 or thereabouts to send the output pulse. To reduce sensitivity, you could change that command to PULSOUT n,39000,1 or 40000 or higher. Or 36000 or lower.

    A simple hardware fix is to increase the value of the series resistor going to the IR LED which sends the 38000 kHz pulse.

    Erco, if you increase the resistor going to the IR LED, that makes the light dimmer right?

    I know this is kind of a stupid question, but I am still grasping the concepts of resistors.
  • ercoerco Posts: 20,256
    edited 2014-10-27 13:37
    ValeT wrote: »
    Erco, if you increase the resistor going to the IR LED, that makes the light dimmer right?

    I know this is kind of a stupid question, but I am still grasping the concepts of resistors.

    Yes, that's exactly what happens. A higher value resistor allows less current flow through the LED, thus dimming it. And there's no such thing as a stupid question, Pal!
  • ValeTValeT Posts: 308
    edited 2014-10-27 13:38
    Thanks for the kind support Erco!
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