Blynk_ControlRelay.ino

/*
  Created by Thanapon@Arduino2Day.com
*/
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxxxxxxxxxxxxxxxxx";
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "xxxxxxxxxx";
char pass[] = "xxxxxxxxxx";
bool state = 0;
BlynkTimer timer;
BLYNK_WRITE(V1)
{
  int pinValue = param.asInt(); // assigning incoming value from pin V1 to a variable
  Serial.print("V1 Slider value is: ");
  Serial.println(pinValue);
  if (pinValue)
  {
    state = 1;
  }
}

void myTimerEvent()
{
  // You can send any value at any time.
  // Please don't send more that 10 values per second.
  if (digitalRead(D2) == 1)
  {
    Blynk.virtualWrite(V1, 0);
  }
}
void setup()
{
  // Debug console
  // Serial.begin(9600);
  pinMode(D2, OUTPUT);
  digitalWrite(D2, HIGH);
  Blynk.begin(auth, ssid, pass);
  timer.setInterval(1000L, myTimerEvent);
}

void loop()
{
  Blynk.run();
  timer.run();
  if (state == 1)
  {
    Serial.println("1");
    digitalWrite(D2, LOW);
    delay(200);
    digitalWrite(D2, HIGH);
    Serial.println("0");
    state = 0;
  }
}