I know I'll probably get some people saying this is unpossible, but this is what I've been dealing with for the past 2 days.
I am in the process of building an escape room. I have an arduino nano connected to a PIR sensor, 4 LEDs and a button. It is supposed to run the bulk of its script after the button is pushed. Works like a champ.
A few feet to the left I have a 12v magnetic lock. A foot below I have an RFID detector. 18" to the right, I have 3 8 channel relay boards.
At the moment, this PIR sensor system is only connected to my laptop. Completely electrically isolated from the rest of the room.
If I put an RFID card up against that sensor, a relay is triggered closed for 5 seconds. Immediately when that relay opens, it causes the completely disconnected Arduino nano to fire off its sequence as if the button had been pushed. I've ruled out loose wires and all sorts of jiggling. The only way I can get it to fire is to either
A. Push the button as intended B. Have that disconnected relay close and reopen.
Can someone a lot smarter than me tell me what in the world is going on???