1

I have an NPN LJ12A3-4-Z/BX proximity sensor that I want to use to detect water usage on a water meter that has a rotating iron disk.

To make sure I don't overpower the 3.3v GPIO inputs I want to use a reed relay SIP-1A05 to keep the 5v circuit separate. But connecting input pin 18 to the relay does not seem to work.

Do I also need to connect the ground? If so, where to? With a resistor to the relay also?

Thanks water meter circuit

1

Answering my own question so other people can learn from this (after help from Electrical Engineering SE). I should have connected brown and black to the reed relay, not black and blue. Also add pull down resistor to the ground.

corrected circuit

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.