This is a break out of a larger arduino sketch that I'm using to run the plinko board project. I'm running into issues adding interrupts instead of querying the state in the loop.

debugging_interrupts.ino

// * define all of the pins
// * each of these is marked as an interruptable pin on the M0 Adalogger
#define break_beam_ZERO 14
#define break_beam_ONE 11
#define break_beam_TWO 10
#define break_beam_THREE 9
#define break_beam_FOUR 6
#define break_beam_FIVE 5

// * Init some state tracking vars
int breakBeamState_ZERO;
int breakBeamState_ONE;
int breakBeamState_TWO;
int breakBeamState_THREE;
int breakBeamState_FOUR;
int breakBeamState_FIVE;

setup()
{
    Serial.begin(115200);
    Serial.println("Starting up");

    // * Set up each of the break-beam pins
    // * Note that this is a modification of the original pinout settings that I was using
    // * when I was trying to query the state in the loop.
    // * The original settings looked like this:
    // pinMode(break_beam_ZERO, INPUT);
    // digitalWrite(break_beam_ZERO, HIGH);

    pinMode(break_beam_ZERO, INPUT_PULLUP);
    digitalWrite(break_beam_ZERO, HIGH);
    attachInterrupt(break_beam_ZERO, setBreakbeamState, LOW);

    pinMode(break_beam_ONE, INPUT_PULLUP);
    digitalWrite(break_beam_ONE, HIGH);
    attachInterrupt(break_beam_ONE, setBreakbeamState, LOW);

    pinMode(break_beam_TWO, INPUT_PULLUP);
    digitalWrite(break_beam_TWO, HIGH);
    attachInterrupt(break_beam_TWO, setBreakbeamState, LOW);

    pinMode(break_beam_THREE, INPUT_PULLUP);
    digitalWrite(break_beam_THREE, HIGH);
    attachInterrupt(break_beam_THREE, setBreakbeamState, LOW);

    pinMode(break_beam_FOUR, INPUT_PULLUP);
    digitalWrite(break_beam_FOUR, HIGH);
    attachInterrupt(break_beam_FOUR, setBreakbeamState, LOW);

    pinMode(break_beam_FIVE, INPUT_PULLUP);
    digitalWrite(break_beam_FIVE, HIGH);
    attachInterrupt(break_beam_FIVE, setBreakbeamState, LOW);
}

loop()
{
    // * Check our state. In theory these should be updated by the ISR, but I'm not seeing the changes
    Serial.println("===================");
    Serial.println(breakBeamState_ZERO);
    Serial.println(breakBeamState_ONE);
    Serial.println(breakBeamState_TWO);
    Serial.println(breakBeamState_THREE);
    Serial.println(breakBeamState_FOUR);
    Serial.println(breakBeamState_FIVE);
    Serial.println("===================");
    delay(500);
}

void setBreakbeamState()
{
    // * Reading in the state of the break beam pins
    breakBeamState_ZERO = digitalRead(break_beam_ZERO);
    breakBeamState_ONE = digitalRead(break_beam_ONE);
    breakBeamState_TWO = digitalRead(break_beam_TWO);
    breakBeamState_THREE = digitalRead(break_beam_THREE);
    breakBeamState_FOUR = digitalRead(break_beam_FOUR);
    breakBeamState_FIVE = digitalRead(break_beam_FIVE);

    // * I tried hard coding the zero to test and see if the interrupt was getting called at all (it's not).
    // breakBeamState_ZERO = 0;
    // breakBeamState_ONE = 0;
    // breakBeamState_TWO = 0;
    // breakBeamState_THREE = 0;
    // breakBeamState_FOUR = 0;
    // breakBeamState_FIVE = 0;
}