I have a Xiaomi wireless door/window sensor from which I’ve disconnected the reed switch and soldered on wires. I’ve done this with a few of these sensors (about four others) and they all work fine. However, with this sensor, if I touch ONE of the ends of the wire (not the other) the circuit is deemed to be completed. If I touch the other end of the soldered on wire, nothing.
I’ve removed the wires and now if I touch one or other of the solder pads where the wires were soldered onto, I get no reaction, as you would expect. If I connect both pads with tweezers or wire, I get the reaction you’d expect - circuit completed!
Anyone know what was going on with the wires?! I’ve never had this happen before. Could a bad solder joint cause this? If so, how?
This is just academic - I have desoldered the wires and the problem has gone away.