Final Central Server.ino

#include <ESP8266WiFi.h>
#include <espnow.h>
#include <Arduino.h>
#if defined(ESP32)
  #include <WiFi.h>
#elif defined(ESP8266)
  #include <ESP8266WiFi.h>
#endif
#include <Firebase_ESP_Client.h>

#include "addons/TokenHelper.h"
#include "addons/RTDBHelper.h"
#define WIFI_SSID "Inter"
#define WIFI_PASSWORD "#helloworld"
#define API_KEY "AIzaSyA5bJvaz2rlyiGu3MtKcDLCo7Ycd4OZzkM"
#define DATABASE_URL "https://inter-iit-60162-default-rtdb.firebaseio.com/" 
FirebaseData fbdo;
FirebaseAuth auth;
FirebaseConfig config;
unsigned long sendDataPrevMillis = 0;
int count = 0;
bool signupOK = false;



// Structure example to receive data
// Must match the sender structure
typedef struct struct_message {
    int id;
    int x;
    int y;
} struct_message;

// Create a struct_message called myData
struct_message myData;

// Create a structure to hold the readings from each board
struct_message board1;
struct_message board2;

// array of struc
struct_message boardsStruct[2] = {board1, board2};

// Callback function that will be executed when data is received
void OnDataRecv(uint8_t * mac_addr, uint8_t *incomingData, uint8_t len) {
  char macStr[18];
  Serial.print("Packet received from: ");
  snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
           mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
  Serial.println(macStr);
  memcpy(&myData, incomingData, sizeof(myData));
  Serial.printf("Board ID %u: %u bytes\n", myData.id, len);
  // Update the structures with the new incoming data
  boardsStruct[myData.id-1].x = myData.x;
  boardsStruct[myData.id-1].y = myData.y;
  Serial.printf("x value: %d \n", boardsStruct[myData.id-1].x);
  Serial.printf("y value: %d \n", boardsStruct[myData.id-1].y);
  Serial.println();
}
 
void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  
  // Set device as a Wi-Fi Station and soft access simultaneouly
  WiFi.mode(WIFI_AP_STA);   // added
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    while (WiFi.status() != WL_CONNECTED){
    Serial.print(".");
    delay(300);
  }
  
  config.api_key = API_KEY;
  config.database_url = DATABASE_URL;
if (Firebase.signUp(&config, &auth, "", "")){
    signupOK = true;
  }
  else{
    Serial.printf("%s\n", config.signer.signupError.message.c_str());
  }

  config.token_status_callback = tokenStatusCallback;
  
  Firebase.begin(&config, &auth);
  Firebase.reconnectWiFi(true);
 

  // Init ESP-NOW
  if (esp_now_init() != 0) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }
  
    // getting recv packer info
  esp_now_set_self_role(ESP_NOW_ROLE_SLAVE);
  esp_now_register_recv_cb(OnDataRecv);
}

void loop(){
   if (Firebase.ready() && signupOK && (millis() - sendDataPrevMillis > 15000 || sendDataPrevMillis == 0)){
    sendDataPrevMillis = millis();
    int a=random (1,20);
    int b=random (1,20);
    int c=random (1,20);
    
    bool sent1=Firebase.RTDB.setInt(&fbdo, "sensor 1/ate", a);
    bool sent2=Firebase.RTDB.setInt(&fbdo, "test/b", b);
    bool sent3=Firebase.RTDB.setInt(&fbdo, "test/c", c);
    if(sent1 || sent2 || sent3) 
    Serial.print("Scuces");
  }
}