unsigned long timerPreset;
unsigned long timerVal;
const uint8_t sensor6button = 11;
const uint8_t LED = 5;


void setup() {
pinMode(sensor6button, INPUT_PULLUP);
pinMode(LED, OUTPUT); // wired as common anode
timerPreset = 1500;

}

void loop() {
   // as long as button is pressed, reset the timer
   //
  if(digitalRead(sensor6button) == LOW)
   timerVal = millis();

  // if button is not pressed the timer increments to preset
//
  if(millis()-timerVal > timerPreset) digitalWrite(LED, HIGH); // LED off
 
  else digitalWrite(LED,LOW); // LED on
}