I'm using an esp32 dev board, and a bunch of 5v laser diode emitters pointed an equal number of photocell resistors across a plane. The goal is only to detect when any two or more beams break at the same time.
I could try to wire up one resistor per pin (the 32 has 18 analog pins), which I know enough to do on my own, but that feels stupid. I feel like there is a smarter way to just wire up the photocells so that any simultaneous break of two or more beams will result in a net change that is big enough for me to read on one pin.
To be clear, I don't care when 0 or 1 beam breaks, only 2 or more.
Is there a way for me to wire together the photocells (series? parallel?) so that I can then test what 0 breaks reads at, what 1 reads at, and then act on 'whatever 2 or more breaks' reads at? What would that circuit look like?