void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP321");
  pinMode (15, OUTPUT);
  pinMode(2, INPUT_PULLUP);
}

void loop() {
  delay(10); // this speeds up the simulation
  int a = digitalRead(2);
  digitalWrite(15,a);//if 1-a ,under 100 lux nothing glows relay&LDR glows above 110 
}                     //a,under 110 relay, above LDR glows