I think I may have figured it out. Will this work:
int buttonState = 0; // variable for reading the pushbutton status
int timeleft = 0;
void setup() {
// initialize pins
pinMode(D5, OUTPUT);
pinMode(D1, INPUT);
Serial.begin(9600);
}
void loop() {
delay (10);
// read the state of the pushbutton value:
buttonState = digitalRead(D1);
if (buttonState == HIGH) {
(timeleft == 900000); // sets time to 15 min
digitalWrite(D5,HIGH); // set D5 HIGH
Serial.print("Reset to 15 min");
delay(2000);
Serial.print(timeleft);
}
else {
(timeleft =- 10);
Serial.print(timeleft);
}
if (timeleft < 0) {
digitalWrite(D5,LOW);
Serial.print("Expired");
(timeleft == 0);
}
}