#define SERIAL_ADDRESS 2

void setup() {
   pinMode(7, OUTPUT);
   pinMode(17, OUTPUT);
   Serial.begin(115200);
   Serial1.begin(9600);

   digitalWrite(17, LOW);
}

int receivedByte;

void loop() {
  while (Serial1.available() == 0) {;}
  receivedByte = Serial1.read();
  Serial.print(receivedByte, HEX);
  
  if (receivedByte == SERIAL_ADDRESS) {
    digitalWrite(7, HIGH);
    Serial.write(" This is for me!\r\n");

    while (Serial1.available() == 0) {;}
    receivedByte = Serial1.read();

    Serial.print(receivedByte, HEX);
    
    if (receivedByte == 1) {
      Serial.write(" ON\r\n");
      digitalWrite(17, HIGH);
    } else {
      Serial.write(" OFF\r\n");
      digitalWrite(17, LOW);
    }
  } else {
    digitalWrite(7, LOW);
    Serial.write(" This is not for me!\r\n");

    while (Serial1.available() == 0) {;}
    receivedByte = Serial1.read();

    Serial.print(receivedByte, HEX);
    Serial.write(" IGNORED\r\n");
  }
}