MySensors Ping Pong (gateway <--> sensor)

gateway.ino

#define MY_DEBUG

#define MY_RADIO_NRF24
#define MY_RF24_CHANNEL 69
#define MY_NODE_ID 0
#define MY_GATEWAY_SERIAL

#include <MySensors.h>

#define PONGNODEID 15

MyMessage msg(MY_NODE_ID, V_VAR1);

void setup(){
  msg.setDestination(PONGNODEID);
}

void presentation(){}

long lastSent = 0;
void loop(){
    if(millis() - lastSent >= 3000){
      lastSent = millis();
      send(msg.set("Message Gateway -> Pongnode"));
    }
}

pongnode.ino

#define MY_DEBUG 

#define MY_RADIO_NRF24
#define MY_RF24_CHANNEL 69
#define MY_NODE_ID 15

#include <SPI.h>
#include <MySensors.h>

#define GATEWAYID 0

MyMessage msg(MY_NODE_ID, V_VAR1);

void setup()  { 
  msg.setDestination(GATEWAYID);
}

void presentation()  {
  sendSketchInfo("Pong Node", "1.0");
}

void loop(){}

void receive(const MyMessage &message){
  send(msg.set("Mesage Pongnode -> Gateway"));
}

repeater.ino

#define MY_DEBUG 

#define MY_RADIO_NRF24
#define MY_RF24_CHANNEL 69
#define MY_NODE_ID 10

#define MY_REPEATER_FEATURE

#include <SPI.h>
#include <MySensors.h>

void setup()  { }

void presentation()  {
  sendSketchInfo("Repeater Node", "1.0");
}

void loop(){}