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Sumobot IR Detectors malfunctioning? — Parallax Forums

Sumobot IR Detectors malfunctioning?

tpyo72682tpyo72682 Posts: 5
edited 2009-02-28 15:28 in Robotics
Hello!

I recently bought a Sumo Competition Kit and have been having success with setting it up, but I am now on "Testing the IR Pairs" on page 39 of the Sumobot Manual.

Basically, this is the step where you mount IR LEDs and IR Detectors on the left and right side of the robot. The LEDs emit a frequency and when something is in front of those LEDs, like a hand, the IR Detector will pick up the signal from the reflection.

Out of all of the IR Detectors that came with the set, three of them work perfectly. The ones that work will show a '1' on my debugger when I put my hand in front of the sensor, and a '0' when nothing is in front of it.

When I use any other IR Detector other than those three, a '1' will show up when my hand is in front of it, but when nothing is in front of it the debugger will read '0' MOST of the time, but will have small flickers of a '1' reading.

This makes me think that the IR Detectors are too sensitive. I have been able to reproduce the error by switching back and forth from the Bad IR Detectors and the good IR detectors. I have put the bad Detectors in both of my Sumo robots and the problem always seems to stay with Robot with the Bad IR detector. The IR LEDs I have also been replacing, and I made sure that the IR LEDs weren't leaking any light from the back of their casings. When I remove the IR LED completely the IR Detectors do not pick up any readings and the debugger reads '0', as it should. I just found it strange that ALL of the IR Detectors, with the exception of three of them, are working.

Do I just need to order more Detectors or is there something else that I have missed? Are these IR Detectors tempermental in house lights that are dim?

Comments

  • dandreaedandreae Posts: 1,375
    edited 2009-02-27 15:46
    What type of environment are you working in, is there a lot of noise the area?· I've noticed in the past that some fluorescence lights that have a bad ballast, it will cause false readings.·

    Dave

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    Dave Andreae

    Parallax Tech Support·
  • GWJaxGWJax Posts: 267
    edited 2009-02-27 23:51
    As I see it, if 3 are working in the same environment and only one flickers on and off it does sound to me that the IR-RX is going bad. You can go to your local Radio Shack and pick up another IR-RX and use that or if you have a broken VCR,TV,DVD player, ect grab it from that so it's free, these all work in the 38 Mhz to 40 Mhz range but be sure to look up the datasheet for that part number on the web as the pin layouts will be different. If you have trouble in finding the Datasheets for one let me know and I'll get it to ya.

    Jax

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    If a robot has a screw then it must be romoved and hacked into..
  • tpyo72682tpyo72682 Posts: 5
    edited 2009-02-28 06:51
    Thank for you for your responses.

    I started to debug it by completely removing both IR detectors and IR Leds and I noticed that one of my PWM cables for the QTI sensors that go on the bottom had been plugged in the wrong way.

    I idiotically fixed the problem and reloaded the software, and they both seem to be working fine!

    Sorry for the trouble!
  • GWJaxGWJax Posts: 267
    edited 2009-02-28 15:28
    Great I'm glad it was only a wiring problem! Happy Sumo Bot wrestling!

    Jax

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    If a robot has a screw then it must be romoved and hacked into..
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