#define S0  2
#define S1  3
#define S2  4
#define S3  5

void setup(){
  Serial.begin(9600);
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);
  pinMode(S3, OUTPUT);
}

void loop(){
  for (int i = 0; i < 16; i++){
    read4067(i);
    float izm = 5.00/1023*analogRead(A0);
    Serial.println(String(i)+" = "+String(izm)+" V");
  }
  delay(5000);
  Serial.println();
}

int read4067(byte ch){
  digitalWrite(S0, (ch & 0b0001));
  digitalWrite(S1, (ch & 0b0010)>>1);
  digitalWrite(S2, (ch & 0b0100)>>2);
  digitalWrite(S3, (ch & 0b1000)>>3);
}