#define SERIN_PIN 3
#define CLK_PIN 2
#define SHLD_PIN 4


void setup() {
  pinMode(CLK_PIN, OUTPUT);
  pinMode(SHLD_PIN, OUTPUT);
  pinMode(SERIN_PIN, INPUT);
  Serial.begin(9600);
}

void loop() {
  // SH_PIN is HIGH as default
  // Put SH_PIN to LOW and then rise up to HIGH to read the values
  digitalWrite(SHLD_PIN, HIGH);
  digitalWrite(CLK_PIN, HIGH);
  delay(1);
  digitalWrite(SHLD_PIN, LOW);
  digitalWrite(CLK_PIN, LOW);
  delay(1);
  digitalWrite(SHLD_PIN, HIGH);
  digitalWrite(CLK_PIN, HIGH);
  delay(1);

  // REad value from register
  unsigned int val =  shiftIn(SERIN_PIN, CLK_PIN, LSBFIRST);
  //Serial.print("Input value: ");
  Serial.println(val, BIN);
  delay(2500);
}