I'm trying to make a simple motion sensor that connects up a PIR sensor to a wireless doorbell so when the sensor is triggered to doorbell will ring. Simple enough I thought, I've connected wires from the alarm pins of the sensor and soldered them across the doorbell switch. This works fine, when the sensor is triggered the doorbell does indeed go off. The problem is it also sounds at seemingly random short intervals making the device pretty much useless. From what I can tell it isn't actually the sensor giving false alarms (the sensor LED doesn't light up when the doorbell sounds and the doorbell will still ring if the sensor is entirely covered) but somehow putting power into the PIR is causing the doorbell to sound - its not interference from another wireless source since it only happens when the PIR is powered. I got the PIR off ebay so I have no instructions - a previous thread on here was talking about the jumpers, what do they do? Anyone have any ideas? Thanks

Hello, You

Oh dear, I clearly don't know what I'm doing! Ok, so normally - with no movement - there will be current through pins 3 and 4 of the detector? That could explain my problems! Could you recommend a suitable relay that would do the job? Very basic instructions would be appreciated too. Thanks

Hello, I have attached a wiring diagram.

Maplins Website I think this 12volt relay should be fine. It

Thanks for your help, I'll give it a go and see what happens. A simple way sounds ideal!