// the stup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output
pinMode (D7, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {

digitalWrite(D7,HIGH);  //turn the LED on (HIGH is the voltage level)
delay(1000);           // wait for a second
digitalWrite(D7,LOW); // turn the LED off by making the voltage LOW
delay(1000);         // wait for a second
}