Calling all electrical engineers and sparks….pir to smart relay

Evening, I’m having trouble getting a standard 240v pir to trigger a smart relay. I’ve used different pirs along with different smart relays. It seems the problem is the same. The switching live feed to have current in it which interferes with the relay. I’ve tried various resisters and ones that people say work 2w 330k however no joy. I’m now going down the finder relay route then to smart switch however they are big and it causes issues with space. Has anyone else managed to get a normal pit working using a resister?

I thought this sounded familiar... so is this a continuation of this older post? Wiring experts and coding hero’s I need your help!

you are correct however i'd got further with the problem and it looked like resisters were needed. In other news....cracked the hardware side of it using a finder relay with the pir switch wire going into that then into the smart relay. Works a treat!

Just be careful with resistor and 240VAC. It could get toasty if you are using the wrong value.

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Indeed watts = ohms * current^2
Or watts = volts * current in amps
Volts will be say 110V or even 230/240V
So even passing just 10ma at 240v will be 2.4 W ! (or 1.1w at 110v).
Often resistors are just 1/8 or 1/4 watt rated.

Ah that makes sense why it’s not worked. Safety wise would prefer to use the relay option if that’s the case. Thanks

PIRs typically give a very short pulse ‘trigger’ output on motion. Often just a few hundred mS.. This won’t work well with a relay.
Security light PIR’s give a sustained output, equal to the time the light remains on after being triggered.