Help with PIR motions sensor to an LED Light.

Discussion in 'General Electronics Chat' started by ADSL J, Dec 31, 2018.

  1. ADSL J

    Thread Starter New Member

    Dec 31, 2018
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    Hello

    I am planning to add a PIR motion sensor to an existing LED light, which is connected to the AC power. I understand that the LED lights work on DC and there is a driver included with these commercially available lights. AC is connected to the driver and the drivers output to the LED strip inside the light.

    If I buy a PIR motion sensor
    https://www.banggood.com/Mini-IR-In...-p-1015337.html?rmmds=search&cur_warehouse=CN

    like the above, do I need a separate 12V power supply or can i use the output of the LED driver to power it and then connect it to the LED strip?
    Thanks
    AJ
     
  2. ericgibbs

    Moderator

    Jan 29, 2010
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    hi A,
    Welcome to AAC.
    Your image is not visible.
    E
     
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  3. Raymond Genovese

    Well-Known Member

    Mar 5, 2016
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    The device that you linked to is the very common "AM312" board.

    Here is a link to, what looks to be, the identical board, with a schematic. Note that the PIR board has a regulator on it so that it can operated from a relatively wide DC voltage range (specified as 2.7 - UP TO 12V). So, yes, it can probably operate at the high limit from the LED power supply.

    There is another concern, however, and that is how to switch the LED panel using the signal out pin on the PIR board - do you have a strategy for that?
     
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  4. ADSL J

    Thread Starter New Member

    Dec 31, 2018
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    [​IMG]

    Sorry was not able to upload earlier.


     
  5. ADSL J

    Thread Starter New Member

    Dec 31, 2018
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    Thanks Raymond for the kind reply. Well I am still blank on what to do with this? What I am thinking is to get a couple of PIR senor and to test it. I believe that the 3 pins will be one for the input and the other for the output. and the third one a common ground. let me tell you that I am not an expert in electronics. so when there is a motion detected the circuit will close and the current will flow through the sensor to the led's. But I need a mechanism to bye pass the motion sensor also. Any ideas are welcome.

     
  6. Raymond Genovese

    Well-Known Member

    Mar 5, 2016
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    On the one hand, I think you should have fun experimenting with the PIR board - there is a ton of info on the AM312 board and videos and projects and the like.

    On the other hand, I am almost of the mind that you might do better just buying an off-the-shelf unit that is designed for this - they are cheap and all over the place also. There is more to consider when DIY - for example, you can't just drive the LEDs with the signal out from the AM312, you need to design a switch that will do that.

    Before going to far, I suggest that you do some searches as there are many such projects that have been written up.
     
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  7. ericgibbs

    Moderator

    Jan 29, 2010
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    hi A,
    Those PIR modules output approx +3V [ at approx 3mA max] when activated, so an amplifier and driver is required if you want to drive LED's.
    Post details of the LED lamps you are considering and if possible a link, we can then suggest amplifiers.
    E
     
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  8. MisterBill2

    Distinguished Member

    Jan 23, 2018
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    E.G. is totally correct, you will need an interface between the low level logic output of the PIR sensor and anything except a logic input that you want to use it to control. I don't know if the LED light that you want to use it with even has accessible connections aside from the AC mains terminals. To switch any useful amount of power you will need at least one stage of amplification between the sensor package and the power switching device. While the LED light that you have does include some sort of power conversion circuit, there may be no access to that circuit available. In addition, any controlling of mains power immediately has a serious set of safety requirements to follow. So even when you get the interface circuit working you will still need to package it safely. I am not attempting to discourage you, but only to assure that you understand the safety considerations in dealing with mains power.
     
    Last edited: Dec 31, 2018
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