I was thinking of using multiple analog light sensors (variable resistance by light), but basically I only need to know if there is "a lot of light" or "not a lot of light". And would like to use interrupts.
Since I'm using multiple analog inputs, I can't set the ADC module to interrupt on a specific voltage, for each of the (5?) sensors? I'd like to do this withouth using a external comparator.
I've checked the ATMega328p datasheet (going to use Arduino Nano probably).
The fun thing, however, is that on 5V a high signal is >2.6V and a low signal is <2.2V
What does this mean for the grey area? Would my inputs be glitching randomly? Would they maintain high, until below 2.2V and maintain low until above 2.6V? Or can the switching point be any where between that (and is it different per chip or pin?
EDIT: I've checked, my voltage divider circuit has 0.6V for "nothing" and 3V for "interrupted", so it should work neverthless. Though, I'm still interested in how the grey threshold area behaves.