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IR emitter reciever problems — Parallax Forums

IR emitter reciever problems

lardomlardom Posts: 1,659
edited 2012-12-19 18:00 in Accessories
It is always harder than you think it is. I wanted to experiment with IR detection on the Propeller to test on a wall following robot. "Follow the schematic and run the program. Double check and rerun. Remove the resistor and rerun"...and so on. I'm stuck. I used a digital camera to see if the ir led was working and compared it to a TV remote control. It was faint but the schematic called for a 1K resistor. The remote control did cause the PST to change state. I need help.


IR emitter and reciever.jpg
IR emitter and reciever.jpg
1024 x 768 - 89K

Comments

  • John AbshierJohn Abshier Posts: 1,116
    edited 2012-12-19 09:39
    Since the Propeller is a 3.3 volt device I would use a lower current limiting resistor. R = (3.3 - LED forward voltage drop) / desired current. 180 ohms for 10 mA. Also, your LED is aimed vertically and the detector is aimed horizontally.

    John Abshier
  • lardomlardom Posts: 1,659
    edited 2012-12-19 18:00
    @John Abshier, Thank you. I made a dumb mistake. I put the what I thought was the 'emitter', the shield and the sensor in the same compartment of my parts box where it's been for at least a year. I went to RadioShack and now I realize that the IR LED is bluish. :innocent:
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