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PIR detector 555-28027 rev.B doesn't stay on — Parallax Forums

PIR detector 555-28027 rev.B doesn't stay on

cap_jackcap_jack Posts: 9
in Accessories
Hello, I have attached a Parallax PIR detector to digital pin 8 of an Arduino Uno. My simple program looks for the PIR signal and plays some wav files. The detector turns off even when my hand is 6 inches in front of it. Even if I wave my hand it turns off but not as soon. The documentation says for Rev A, "Jumper selects single or continuous trigger output mode" but there is only one jumper and I tried both settings. I believe Rev B jumper sets distance but I am confused. Please help me understand why the detector doesn't stay on. Thank you!

Comments

  • hatallicahatallica Posts: 175
    When the PIR detector is powered, you must allow approximately 40 seconds for it to initialize. The output is not predictable during this time.

    After initialization, the output will become high for only a few seconds after detecting movement.

    On Rev.B, the jumper only sets the sensitivity or distance that it is capable of sensing.

    I believe that there is a red LED behind the lens that will also glow when the detector is triggered. This will provide visual confirmation that the output is high.

    https://www.parallax.com/downloads/pir-sensor-rev-b-product-guide
    The product page also has additional resources that describe specific projects using this sensor.


    So, if you allow time for initialization and verify that the red glow is not indicating motion, then please attach a photo or drawing of your electrical connections.
  • xanaduxanadu Posts: 3,347
    That is interesting, the datasheet mentions holding the output pin high when the jumper is in the "H" position and "triggered repetitively". I have not experienced that using the same sensor. Both modes seem to go high then low, I thought the jumper was a range adjustment. Are you using it as a proximity sensor?

    With PIR once the motion stops the sensor has done its job. The PING or IR pairs would allow you to detect motion along a very narrow path, and tell you how close the object is, and if it is still blocking the path. Essentially giving you a signal for both motion and stopped objects, but with a much narrower beam than the PIR.
  • hatallicahatallica Posts: 175
    xanadu wrote: »
    That is interesting, the datasheet mentions holding the output pin high when the jumper is in the "H" position and "triggered repetitively". I have not experienced that using the same sensor. Both modes seem to go high then low, I thought the jumper was a range adjustment.

    For Rev.B, the jumper controls sensitivity/range/distance. For Rev.B, no controls exist for setting high/low and no controls exist for single/continuous triggering.

    The H/L jumper only applies to Rev.A, and is only described as part of the Revision History of the data sheet.
  • xanaduxanadu Posts: 3,347
    Gotcha, I missed that hatallica had rev B and was looking at the PIR rev A datasheet.
  • PublisonPublison Posts: 12,366
    The original title of the thread had REV A in it, but I guess it got changed. That threw me too.
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