int buttonHighLow = 0;

void setup() {                
  pinMode(7, OUTPUT);
  pinMode(3, INPUT);  
}

void loop() {
  buttonHighLow = digitalRead(3);
  
  if (buttonHighLow == HIGH) { 
    digitalWrite(7, HIGH);   
    delay(1000);             
    digitalWrite(7, LOW);    
    delay(1000);
  }
  else {
    digitalWrite(7, LOW);
  }
}