const unsigned long Minutes = 60ul * 1000ul;
const unsigned long SevenMinutes = 3000;
const unsigned long EightMinutes = Minutes * 8;
#define pin3 3
static unsigned long startTime = millis(); 
//static unsigned long startTime = 0;
unsigned long elapsedInterval;
unsigned long now;
static unsigned long previousMillis = 0; 
unsigned long currentMillis = 0;
static int latch = 0;
const long interval = 4000;           
int led2 = 2;
static int lastButtonState = 1;  
int buttonState = 1;
void setup() {
  Serial.begin(9600);
Serial.println();
static int dingo;

pinMode(pin3,INPUT_PULLUP);
pinMode(led2,OUTPUT);

}
void loop() {
//WORKIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIING

//delay(500);
 
 
 buttonState = digitalRead(pin3);
 unsigned long elapsedInterval = millis() - startTime;

 startTime=millis(); //Updates startTime.
  
 if(digitalRead(pin3)==LOW && buttonState != lastButtonState){ //this is your trigger
 now=millis(); //starts the Clock because now will not update with startime/Millis till button state change.
 latch=1; //Captures moments of truth
 }

  // latch is important because it maintains state even as lasbutton state changes after initial press
  
  Serial.println(now);   
    
  if (latch==1){
  if (millis() - now >= interval ) {//&& latch ==1
 
  digitalWrite(led2, HIGH);
  delay(800);
  digitalWrite(led2, LOW);
  latch = 0;
  }
  }
  lastButtonState = buttonState; 

  /* else if(digitalRead(pin3)==HIGH) {  
 latch = 0;  // Prevents any accidental switch press from triggering led.
 }*/
 }