# Wiring. 12 volt wireless relay and pir.



## Dpyle (Aug 15, 2021)

Anyone have any idea how to wire a wireless 12volt relay and 12 volt pir to a 12volt air solenoid valve without back feeding power into relay or pir. Trying to use two triggers independently.


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## corey872 (Jan 10, 2010)

Welcome to the forum! If I interpret this correctly you want to use either the wireless relay or the PIR to run an air solenoid?

Based on the assumption both of those devices have relay outputs with NO (normally open) and NC (normally closed) contacts, and have the current capacity to run the air solenoid directly, then I think the attached schematic should work. Either device could trigger and send power to the solenoid. There is no real 'back feeding' because the opposite device would be open. Even if they trigger together, it would basically be just the same 12V source connected to the same 12V wire that either one could connect anyway.

I do show a freewheeling / flyback diode on the air solenoid just to dampen any voltage spikes when the relay opens. This is not explicitly needed, but is a good idea anytime electronics (PIR / Wireless) are involved with an inductive load like the solenoid coil. The solenoid could easily kickback 100's of volts and over multiple triggers, this could possibly short things on the delicate side of the board.


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## Dpyle (Aug 15, 2021)

Thanks Corey for advice.


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