Step-by-Step Guide: Modernize Your Garage Remote with IoT and Control it via Smartphone

				
					#include <PubSubClient.h>
#include <ESP8266WiFi.h>

#define WIFI_SSID "YOURNETWORKNAME"
#define WIFI_PASSWORD "NOVAYOURNETWORKPASSWORD"
#define RELAY 0 // relay connected to  GPIO0

char mqttServer[]  = "broker.hivemq.com"; //change it for your MQTT server IP or network name
int mqttPort  = 1883; //1883 is the default port for MQTT. Change if necessary
char deviceId[]  = "myRelay-001"; //every device should have a different name
char topic[]  = "garage1212"; //the topic should be different for each device as well
//char mqttUser[]  = "YOURMQTTUSERNAME"; // Used for private MQTT broker
//char mqttPassword[]  = "YOURMQTTPASSWORD"; // Used for private MQTT broker
WiFiClient wifiClient;
PubSubClient client(wifiClient);
int status = WL_IDLE_STATUS;

void setup() {
  Serial.begin(9600);
  pinMode(RELAY,OUTPUT);
  digitalWrite(RELAY, HIGH);
  delay(10);
  Serial.println("Let' start now");
}

void loop() {
  if ( !client.connected() ) {
    connect();
  }
  client.loop();
}

unsigned long lastOperation;
const long MIN_OPERATION_INTERVAL = 2000L;

void callback(char* topic, byte* payload, unsigned int length) {
    Serial.print("Message arrived in topic: ");
    Serial.println(topic);
    Serial.print("Message: ");
    signed long now = millis();
    long deltaTime = now - lastOperation;
    if (deltaTime > MIN_OPERATION_INTERVAL) {
      String message = "";
      for (int i = 0; i < length; i++) {
        message = message + (char)payload[i];
      }
      if(message == "1") {
        digitalWrite(RELAY,LOW); // If message "1" received, press the button
        delay(2000);
        digitalWrite(RELAY,HIGH); // After 2 seconds, release button
      }
      Serial.println();
  } else {
    Serial.println("Operation denied right now. Try again later.");
  }
}

void connect() {
  while (!client.connected()) {
    status = WiFi.status();
    if ( status != WL_CONNECTED) {
      WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
      while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
      }
      Serial.print("Connected to ");
      Serial.println(WIFI_SSID);
    }
    client.setServer(mqttServer, mqttPort);
    client.setCallback(callback);
    if (client.connect(deviceId, mqttUser, mqttPassword)) {
      client.subscribe(topic);
      Serial.println("Connected to MQTT Server");
    } else {
      Serial.print("[FAILED] [ rc = ");
      Serial.print(client.state() );
      Serial.println(" : retrying in 5 seconds]");
      delay(5000);
    }
  }
}