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Remote trigger for a Pir floodlight

dr pepper

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I want to trigger a Pir floodlight from my Esp32 webcam.
I tried pointing a remote control style Led at the Pir sensor, but it doesnt trigger it, presumaby the wavelength of the Led is too short.
What could I use to do this that doesnt use watts of power?
 

BradtheRad

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Is your floodlight the kind that is triggered by a warm-blooded animal moving in front of it? Suppose you flash led's in sequence at it... One led from one direction, a second led from another direction? It mimics motion.
 

dr pepper

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Yes it is as you describe.
I assumed just proving some infra red would trigger it, maybe it needs to 'see' motion.
Might try that with a couple of leds.

Edit: Just read on on Pir motion sensors, apparently theres 2 sensors, 1 'watching', and 1 blind, the blind sensor picks up the overall temperature and its used as a reference for the 'watching' sensor to prevent false triggering from temp changes, also some have some kind of filter to remove signals from large flashes of light such as from car headlights, so maybe the way to trigger one is to provide a slow changing amount infra red, and not so bright, so as to mimic what the sensor would 'see' if a person or critter walked past.
 
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BradtheRad

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Yes it is as you describe.
I assumed just proving some infra red would trigger it, maybe it needs to 'see' motion
Perhaps motion is required. I examined a motion detector floodlight, and saw a light grey translucent panel (about 1 inch x 1 inch) covering the detector. It was molded with several convex lens shapes.

I believe the translucent plastic is an infra-red filter (to detect warm-blooded animals), while the lenses focus the rays to create several points of light moving across the detector, as an animal walks through its field of view. Unless there is movement the detector otherwise might continue to be activated indefinitely by its own floodlight.
 

betwixt

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Just read on on Pir motion sensors, apparently theres 2 sensors, 1 'watching', and 1 blind
More usually, the outputs of the two detectors are subtracted and the difference is used as the trigger. Anything common to both sensors is ignored. They are a fraction of a mm apart in a single sensor package so they rely on the lens to split their field of view into alternating strips.

Brian.
 

dr pepper

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That makes sense, so I need a moving light source.
I'll try something this weekend, maybe on a spare sensor I have.
If 2 led's wont do it I'll try a couple of to92 package trannies warmed up to 50 degrees or so, not sure they'd heat up quick enough, maybe driven from a arduino pwm signal tapered off over time might do the trick.
 

betwixt

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Transistors? why not just use resistors?

Beware that there is also a reaction time to take into consideration. The circuit around the sensor will ignore slow changes in level so it is only responsive to moving objects. You may need to have a rapid change in temperature, maybe a small incandescent lamp would do.

Brian.
 

dr pepper

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Noted.
Dunno why I thought of trannies, maybe cos I used one a while back as an oven heater.
 

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