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IR sensors Same but Different? — Parallax Forums

IR sensors Same but Different?

SteveWoodroughSteveWoodrough Posts: 190
edited 2010-12-14 19:10 in Accessories
In my stash of components I have two types of 3 wire IR sensors. Some are all black with a plastic casing and some have a silver metal covering that partially covers the sensor. The silver metal covered ones seem to be far less sensitive than the all black models. Is there a difference?
Thanks,
Steve

Comments

  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-12-14 11:25
    Is there are part number on any of the sensors? There are several different IR sensors which use the same three wire (ground, power, and signal out). Many manufacturers make them and some have the metal shield and some do not. As long as the specs are the same it shouldn't matter if you have the metal shield or not.

    What are you trying to use them for? Is it for distance sensing or for a remote? Those modules come on different I/R detection frequencies so if one is on a different frequency then it may still work but only at a short range. 38Khz is very common but some are on 40Khz, 56Khz, etc

    Robert
  • SteveWoodroughSteveWoodrough Posts: 190
    edited 2010-12-14 11:42
    I'm almost positive I got all these through Parallax. The part numbers vary and some do not have any PN's. Right now I'm just messing with the Propeller and the 12Blocks programming environment, so there is no definite project at the moment. I can get both sensor types to work, it's just that the silver seem to have a MUCH short shorter range and are far less sensitive. Good point about the different frequencies. Let me try that out.

    Thanks,
    Steve
  • ercoerco Posts: 20,255
    edited 2010-12-14 15:23
    Waitrony makes a lot of these IR sensors, and they all have different specs. A few are continuous signal acceptable (steady 38-40 kHz unmodulated IR signal) but most are not; hold a steady signal on those that aren't and the output only goes low for a second.

    Per Robert, there are several center frequencies; you can copy part of the Scribbler or BoeBot program that runs a frequency sweep to test for reflected signals to see what the best frequency is.
  • SteveWoodroughSteveWoodrough Posts: 190
    edited 2010-12-14 19:10
    Thanks, thats good to know. What you described was the same as I experienced where the output seemed to "one shot". After 300 or so msec the output would reset
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