I have a project with a knock sensor reading from an analog pin (it's the basic knock sensor project you can find anywhere). I have an RFID-Rc522 reader connected to the same NANO. As soon as I connect the RFID the analog read seems to be getting values even though I'm not knocking. I can print out the read values and see it "thinks" something is happening on the analog read. I've narrowed it down to happen as soon as I connect the RST pin on the RFID reader to the NANO. I've tried moving the RST connection (which I have a D5) to other digital pins but the same thing happens.
Is there any reason that the RST pin connection would be causing interference to an analog read pin like this?