#define CLK 3
#define SER 4
#define LATCH 2

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(CLK, OUTPUT);
  pinMode(SER, INPUT);
  pinMode(LATCH, OUTPUT);

}

int switches[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

void loadData() {
  // latch the data in
  digitalWrite(LATCH, LOW);
  digitalWrite(LATCH, HIGH);

  // then send a clock pulse and read what is on the data line
  for(int i = 0; i < 16; i++) {
    switches[15-i] = digitalRead(SER);
    digitalWrite(CLK, HIGH);
    digitalWrite(CLK, LOW);
    Serial.print(switches[i]);
  }
  Serial.println();

  // then unlatch the register
  digitalWrite(LATCH, LOW);

}

void loop() {
  // put your main code here, to run repeatedly:
  loadData();
  delay(10);

}