Eye blink sensor circuit diagram and code

 Arduino code:

#define SENSE A0 

void setup()

{

pinMode(SENSE, INPUT);

pinMode(2, OUTPUT);

pinMode(LED_BUILTIN, OUTPUT);

}

void loop()

{

if(digitalRead(SENSE))

{

 digitalWrite(LED_BUILTIN, LOW);

 pinMode(2, LOW);

}

else

{

  delay (2000);

  if(digitalRead(SENSE))

  {

 digitalWrite(LED_BUILTIN, LOW);

 pinMode(2, LOW);

}

  else

  digitalWrite(LED_BUILTIN, HIGH);  

   pinMode(2, HIGH);

  }

}