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how pir sensor works?

Discussion in 'Sensors and Actuators' started by pavan nellutla, Mar 8, 2016.

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  1. pavan nellutla

    pavan nellutla

    Jan 7, 2016
    while i am usint?g a led to test the sensor,the sensor is blinking on a regular basis.What should I do to prevent it?
    Last edited by a moderator: Mar 8, 2016
  2. davenn

    davenn Moderator

    Sep 5, 2009

    you question doesn't make sense. Please try again and describe more clearly what the problem is :)
  3. CapSteel


    Mar 7, 2016
    Make sure you aren't getting any stray infrared signals entering the input to your sensor. Try completely covering the input to the sensor with piece of cardboard for troubleshooting. More details on exactly what you are seeing would help.
  4. ChosunOne


    Jun 20, 2010
    Is this a PIR motion sensor? If it is, you can usually find a brand name and model number on it, which would make it a lot easier to answer your question. There are a lot of PIR motion sensor models out there, and significant differences between them. If you can't find a model number, do you know if it's intended use is for turning on a light, or for use in an alarm system to detect intrusion, or some other purpose? Is it powered by line voltage (220, 240, 110, 120VAC, or whatever your local electricity is) or does it need 12VDC or something else to work?

    I'm experienced with PIR motion sensors used in alarm systems in North America, but there are less complex PIR sensors used for other purposes. The PIRs motion sensors I work with are more sophisticated than most people realize because they use complex signal processing to cull out "random" IR input that would cause false alarms. If what you have is a PIR motion sensor intended for use in an alarm system, I can probably explain what is happening; but if what you have is a PIR sensor intended for use as a light switch when someone enters a room, or approaches the outside of your home, or some other kind of PIR sensor, then my explanation can be much shorter because those sensors are less complex.

    Also, as davenn and CapSteel indicated, you haven't described what you're doing very well. A fuller description of what and how you're testing would be helpful.
  5. cjdelphi


    Oct 26, 2011
    Blinking... are you saying it goes on and off every second?

    Or it goes on, stops for a brief moment then goes on again?
  6. Alec_t


    Jul 7, 2015
    Depending on the spectral response of the PIR sensor you will probably need an IR LED, not a visible-light one, to test it.
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