PIR sensor help PLEASE

Discussion in 'The Projects Forum' started by paresh727, May 10, 2014.

  1. paresh727

    Thread Starter New Member

    May 10, 2014
    Hi Guys

    Its my first time ever posting on this forum. I really need some help and ive seen that the members on this site are very helpful.

    I am trying to build my own 12V PIR outdoor motion sensor. Its a simple device that is powered by a 220 to 12v (1A) power supply. I have a small PIR sensor (3 wires) and a siren. The trouble that i am having is that when ever i switch the system on, the pir is triggering a false alarm whilst is stabilizes and this results in the siren being on for approx 15-20 seconds.

    Is there anyway that i can prevent the siren from going of for the first 15-20 seconds *(i.e. whilst the pir is stabilizing ) ?

    I would really appreciate any help.

    PS. i have already tried installing a capacitor to try and stabilize the voltage during startup, but it doesnt seem to help:(
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    Welcome to the forum!
    Can you post a schematic?
  3. enggricha


    May 17, 2014
    what PIR module are you using...there are PIR modules that already account for these problems.

    you can also use a simple 555 timer to inhibit the siren for a start up time.