#define pin_mode0 '0'
#define pin_mode1 '1'
#define pin_mode2 '2'
#define pin_mode3 '3'
void setup() {
  Serial.begin(9600);
  pinMode(1,OUTPUT);
}
void loop() {
//Serial.write(0x31);
Serial.write(pin_mode0);
delay(1000);
Serial.write(pin_mode1);
delay(1000);
Serial.write(pin_mode2);
delay(1000);
Serial.write(pin_mode3
delay(1000);
}