laser123456.ino

#define LASER_PIN (4)
#define SEND_DELAY (4)

void setup() {
  pinMode(LASER_PIN, OUTPUT);
  Serial.begin(9600);
  sendByte(0x7);
}

void loop() {
  while(Serial.available()) {
    char msg = Serial.read();
    Serial.write(msg);
    sendByte(msg);
  }
}

void sendString(String str) {
  for(int i = 0; i < str.length(); i++) {
    sendByte(str.charAt(i));
  }
}

void sendByte(char byte_to_send) {
  digitalWrite(LASER_PIN, HIGH);
  delay(SEND_DELAY);
  for(int i = 0; i < 8; i++) {
    char bit_value = (byte_to_send >> i) & 1;
    digitalWrite(LASER_PIN, bit_value ? HIGH : LOW);
    delay(SEND_DELAY);
  }
  digitalWrite(LASER_PIN, LOW);
  delay(10);
}