automate macro run via switch input, rather than button click

I presently have a macro that is run via clicking a form button. I need to
automate the process by replacing someone having to manually click the button
with an input from a photo eye switch, or proximity switch. My initial
thought is for Access to constantly monitor for a 0 or 1, or On or Off coming
from the switch, then respond accordingly by running the macro? Has anyone
done something similar? Any suggestions for how I can manipulate Access to
accomplish this automation?

Thank you.

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