ESP8266 Home Automation Relay with Blynk App

/*********************************************************************
 * ESP8266 Home Automation Relay with Blynk App
 * 
 * Control any AC device from your phone
 * Hardware: NodeMCU ESP8266, 5V Relay
 * 
 * Libraries Required:
 * - Blynk (install from Library Manager)
 * - ESP8266 WiFi (built-in)
 * 
 * Pin: D1 (GPIO 5) for relay control
 *********************************************************************/

#define BLYNK_TEMPLATE_ID "YOUR_TEMPLATE_ID"
#define BLYNK_TEMPLATE_NAME "Home Automation"
#define BLYNK_AUTH_TOKEN "YOUR_AUTH_TOKEN"

#include 
#include 

// ============== WIFI CONFIGURATION ==============
const char* wifi_ssid = "YOUR_WIFI_NAME";
const char* wifi_password = "YOUR_WIFI_PASSWORD";

// ============== RELAY PIN ==============
#define RELAY_PIN D1  // GPIO 5
#define LED_PIN D4    // Built-in LED (GPIO 2)

// ============== STATE VARIABLES ==============
bool relayState = false;
bool wifiConnected = false;

// ============== SETUP ==============
void setup() {
  Serial.begin(115200);
  Serial.println(F("\n======================================"));
  Serial.println(F("ESP8266 Home Automation Starting..."));
  Serial.println(F("======================================"));
  
  // Configure pins
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  
  // Initial state - relay OFF
  digitalWrite(RELAY_PIN, HIGH);  // Relay is active LOW
  digitalWrite(LED_PIN, HIGH);   // LED OFF
  
  // Connect to WiFi
  connectToWiFi();
  
  // Initialize Blynk
  Blynk.begin(BLYNK_AUTH_TOKEN, wifi_ssid, wifi_password);
  
  Serial.println(F("Setup complete!"));
  Serial.println(F("Use Blynk app to control the relay."));
}

// ============== MAIN LOOP ==============
void loop() {
  // Run Blynk
  Blynk.run();
  
  // Check WiFi connection
  if (WiFi.status() != WL_CONNECTED) {
    wifiConnected = false;
    digitalWrite(LED_PIN, LOW);  // LED ON when disconnected
  } else {
    wifiConnected = true;
  }
}

// ============== BLYNK CONNECTED ==============
BLYNK_CONNECTED() {
  Serial.println(F("Blynk connected!"));
  Blynk.syncVirtual(V0);  // Sync relay state
}

// ============== VIRTUAL PIN V0 - RELAY CONTROL ==============
BLYNK_WRITE(V0) {
  int pinValue = param.asInt();
  
  if (pinValue == 1) {
    digitalWrite(RELAY_PIN, LOW);   // Turn ON
    relayState = true;
    digitalWrite(LED_PIN, LOW);    // LED ON
    Serial.println(F("Relay: ON"));
  } else {
    digitalWrite(RELAY_PIN, HIGH);  // Turn OFF
    relayState = false;
    digitalWrite(LED_PIN, HIGH);   // LED OFF
    Serial.println(F("Relay: OFF"));
  }
}

// ============== VIRTUAL PIN V1 - TOGGLE BUTTON ==============
BLYNK_WRITE(V1) {
  // Toggle relay
  relayState = !relayState;
  digitalWrite(RELAY_PIN, relayState ? LOW : HIGH);
  digitalWrite(LED_PIN, relayState ? LOW : HIGH);
  
  // Update Blynk
  Blynk.virtualWrite(V0, relayState ? 1 : 0);
  
  Serial.print(F("Toggle: "));
  Serial.println(relayState ? F("ON") : F("OFF"));
}

// ============== HELPER FUNCTION ==============
void connectToWiFi() {
  Serial.print(F("Connecting to WiFi"));
  WiFi.begin(wifi_ssid, wifi_password);
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    Serial.print(F("."));
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println(F(" Connected!"));
    Serial.print(F("IP Address: "));
    Serial.println(WiFi.localIP());
    wifiConnected = true;
  } else {
    Serial.println(F(" Connection failed!"));
  }
}

// ============== END OF CODE ==============