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Sample circuit for motion sensor

Discussion in 'Sensors and Actuators' started by herbey zepeda, Aug 14, 2017.

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  1. herbey zepeda

    herbey zepeda

    Aug 14, 2017
    Last edited by a moderator: Aug 14, 2017
  2. dorke


    Jun 20, 2015
    Welcome to EP.
    No you shouldn't use the circuit at 5.3
    Here is one circuit for you and here is another.

    Hope it helps.
    herbey zepeda likes this.
  3. BobK


    Jan 5, 2010
    BruceMiestE__R likes this.
  4. BruceMiestE__R


    Aug 14, 2017
    The first circuit fills the question. (KISS). The PIR only cares about new heat or heat that disappears. The first Op Amp integrates rate of imbalance either positive or negative into a spike. The three big electrolytic caps balance over a short time and if the first pulse is positive one, the charge on the cap between the first and second amp is pushed in and the op amp turns on completely. At the same time the diode on the input amp forward biases on the input amp to charge the large cap there too. This quickly equalizes the amp to see more heat again and to increase the sensitivity for the expected negative pulse that happiness as people lunge forward and tilt backward while walking. Easy to defeat if your slow. Add a gate shutter synced with and tied to the resets of RS-FF's and the data comes the negative input pin of the the first amp. The set line goes between 22u and the 33k. Reset is a RC tank with another diode across the cap to reset it after the alarm runs a bit. feed resistor charges the cap from the output that can run a 5 V reed relay easy, when the reset activates the output clamps to Gnd and the diode forward biases and discharges the CAP again. But if this is complete crap, just know I can describe how radio shack made the on off remote receiver out of inverts.
  5. kellys_eye


    Jun 25, 2010
    Far be it for me to comment but.........
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