I am having a problem with my shop lights being kept on due to multiple people using the area. I want to install a low voltage motion sensor from an old security system but am unsure how. If it is not possible I will "bite the bullet" and buy one but am trying to do it without expenses. Thanks for your input.

  • you can get a new motion sensor that will work with a relay for $1 on ebay, same price as a relay. – dandavis Oct 26 '17 at 5:04

Easy peasy, have the LV power operate a relay which switches the mains voltage. Alternately you could use all low voltage LED lighting and avoid mains voltage entirely.

  • not all pir modules can drive all relay coils, and many would not safely accept the back current from the released coil. A solid state relay would avoid those problems, but still only works if the PIR outputs high to trigger and emits 5+ volts. also, a naive sensor doesn't latch, so your lights would only be on w/ movement. I like the idea of a relay, but there's a lot that can go wrong with (what should be) a simple circuit. – dandavis Oct 26 '17 at 1:58

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