const int dataPin  = 4;
const int clockPin = 2;
const int latchPin = 3;

void setup() {
  Serial.begin(9600);
  pinMode(dataPin, INPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
}

uint32_t read165() {
  digitalWrite(latchPin, LOW);
  digitalWrite(latchPin, HIGH);

  uint32_t value = 0;

  for (int i = 0; i < 24; i++) {
    value <<= 1;
    value |= digitalRead(dataPin);
    digitalWrite(clockPin, HIGH);
    digitalWrite(clockPin, LOW);
  }

  return value;
}

void loop() {
  uint32_t v = read165();

  for (int i = 23; i >= 0; i--) {
    Serial.print((v & (1UL << i)) ? '1' : '0');
  }
  Serial.println();

  delay(200);
}