Using a PIR to turn a light OFF

[AndyC]

Hi!
I'm trying to find a "reverse PIR" (for want of a better description)! In other words, one where the light is permanently on, then when the PIR detects motion, it turns the light off, then after a fixed period the light automatically comes back on again. Anyone know where I can buy such a thing? I've googled it extensively, but - as you'd expect - all searches end up on pages talking about using PIRs in their normal switching-stuff-on role.
Failing that, anyone know how to make one? I'm an absolute electronics novice, but happy to try to follow a set of instructions!
Cheers,
Andy

 

[vijaykrishna]

use arduino micro controller (cheap, open source, easy to use)

https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/using-a-pir

 

[(*steve*)]

Connect the pir to a relay and use the normally closed contacts to drive the load. When the pir activates, the relay is pulled in, turning the light off.

 

[vijaykrishna]

Connect the pir to a relay and use the normally closed contacts to drive the load. When the pir activates, the relay is pulled in, turning the light off.

nice, i never taught of that.

 

[AndyC]

Cheers guys! Shall ponder the relay option - that sounds like a possibility. Ta!

 

[duke37]

There may be a changeover relay in the PIR or you may be able to fit one.