CODIGO DEL RECEPTOR:


#define ledpin 12
String incomingString;
void setup() {
  Serial.begin(9600);
  pinMode(ledpin, OUTPUT);
  Serial.println("AT+ADDRESS=155");  //0~65535
  delay(500);
  Serial.println("AT+NETWORKID=3");  //=3~15,18(default18)
  delay(500);
  Serial.println("AT+BAND=928000000");  //915M a 928M --> Caso Colombia
  delay(1500);
}
void loop() {
  if (Serial.available()) {
    incomingString = Serial.readString();
    if (incomingString.indexOf("PREND") > 0) {
      digitalWrite(ledpin, HIGH);
      delay(500);
      digitalWrite(ledpin, LOW);
    } else {
      digitalWrite(ledpin, LOW);
    }
  }
}




CODIGO DEL TRASMISOR:

#define ledpin 2
int toggleState_1 = 0;
void setup() {
  Serial.begin(9600);
  pinMode(ledpin, OUTPUT);
  Serial.println("AT+ADDRESS=1");  //0~65535
  delay(500);
  Serial.println("AT+NETWORKID=5");  //=3~15,18(default18)
  delay(500);
  Serial.println("AT+BAND=928000000");  //915M a 928M --> Caso Colombia
  delay(1000);
}
void loop() {
  if (toggleState_1 == 0) {
    Serial.println("AT+SEND=155,5,PREND");  // Direccion, Longitud, Mensage
    digitalWrite(ledpin, HIGH);
    toggleState_1 = 1;
    delay(1500);
  } else {
    digitalWrite(ledpin, LOW);
    toggleState_1 = 0;
    delay(1500);
  }
}