const int latchPin = 5;
const int clockPin = 4;
const int dataPin = 3;
const int buttonPin = 9;

const int numBits = 8; // 8 * number of shift registers

int lastState = HIGH;

void setup() {
  Serial.begin(115200);
  // D5 is PL activate
  // D4 is CP for clock
  pinMode(dataPin, INPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);

}

void readSwitch() {
  // Set PL high
  digitalWrite(latchPin, LOW);
  digitalWrite(latchPin, HIGH);
  Serial.println("Bits: ");
  int bits[] = {};

  for (int i = 0; i < numBits; i++) {
    int bit = digitalRead(dataPin);
    if (bit == HIGH) {
      Serial.print("1");
      bits[i] = 1;
    } else {
      Serial.print("0");
      bits[i] = 0;
    }
    digitalWrite(clockPin, HIGH); // Shift out the next bit
    digitalWrite(clockPin, LOW);
  }

  Serial.println("");
  for (int i = 0; i < numBits; i++) {
    Serial.print(bits[i]);
  }
}

void loop() {

  byte buttonPressed = digitalRead(buttonPin);

  if (lastState != buttonPressed) {
    lastState = buttonPressed;
    if (buttonPressed == HIGH) {
      Serial.println(" released");
      readSwitch();
    }
    if (buttonPressed == LOW) {
      Serial.println(" pressed");
    }
  }

}