Tx 1

// #include <SPI.h>
#include <RF22.h>
#include <RF22Router.h>
#define MY_ADDRESS 12
#define DESTINATION_ADDRESS 5

#define echoPin 8 // attach pin D2 Arduino to pin Echo of HC-SR04
#define trigPin 9 //attach pin D3 Arduino to pin Trig of HC-SR04


RF22Router rf22(MY_ADDRESS);

// Aloha
int sensorVal = 10;
long randNumber;
boolean successful_packet = false;
int max_delay=3000;
int dist_limit = 20;
int level = 1;

// defines distance sensor variables
long duration; // variable for the duration of sound wave travel
int distance = 5; // variable for the distance measurement

void sendData(int data){

    char data_read[RF22_ROUTER_MAX_MESSAGE_LEN];
    uint8_t data_send[RF22_ROUTER_MAX_MESSAGE_LEN];
    memset(data_read, '\0', RF22_ROUTER_MAX_MESSAGE_LEN);
    memset(data_send, '\0', RF22_ROUTER_MAX_MESSAGE_LEN);
    sprintf(data_read, "%d", data);
    data_read[RF22_ROUTER_MAX_MESSAGE_LEN - 1] = '\0';
    memcpy(data_send, data_read, RF22_ROUTER_MAX_MESSAGE_LEN);



    successful_packet = false;
    while (!successful_packet)
    {
      if (rf22.sendtoWait(data_send, sizeof(data_send), DESTINATION_ADDRESS) != RF22_ROUTER_ERROR_NONE)
      {
        Serial.println("sendtoWait failed");
        randNumber=random(200,max_delay);
        Serial.println(randNumber);
        delay(randNumber);
      }
      else
      {
        successful_packet = true;
        Serial.println("sendtoWait Succesful");
      }
    }

}







void setup() {

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
  pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT

  Serial.begin(9600);
  if (!rf22.init())
    Serial.println("RF22 init failed");
  // Defaults after init are 434.0MHz, 0.05MHz AFC pull-in, modulation FSK_Rb2_4Fd36

  if (!rf22.setFrequency(431.0))
    Serial.println("setFrequency Fail");
  rf22.setTxPower(RF22_TXPOW_20DBM);
  //1,2,5,8,11,14,17,20 DBM
  //rf22.setModemConfig(RF22::OOK_Rb40Bw335  );
  rf22.setModemConfig(RF22::GFSK_Rb125Fd125);
  //modulation

  // Manually define the routes for this network
  rf22.addRouteTo(DESTINATION_ADDRESS, DESTINATION_ADDRESS);
  sensorVal = analogRead(A0);                             // Metraei kathe fora kati diaforetiko kai ara bgazei allo seed
  randomSeed(sensorVal);// (μία μόνο φορά μέσα στην setup)
}

void loop() {

  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)


  Serial.print("Distance: ");
  Serial.println(distance);

  if(distance <= dist_limit)
  {
    sendData(level);
    delay(150);
  }

}