const int PUMP_PIN = 9;     // output to mosfet driving the pump
const int BUTTON_PIN = 2;   // input from start button
const int LED_PIN = 13;     // status led

const int PULSE_COUNT = 1000;   // number of pulses to generate
const int PULSE_WIDTH = 22;     // pulse width in milliseconds
const int PERIOD = 200;         // total period in milliseconds (5hz = 200ms)

void setup() {
  // set up pin modes
  pinMode(PUMP_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  // ensure pump is off at startup
  digitalWrite(PUMP_PIN, LOW);

  // initialise serial for debugging
  Serial.begin(9600);
  Serial.println("diesel pump calibration system");
  Serial.println("press button to start 1000 pulses at 5hz");
}

void loop() {
  // wait for button press (active low due to pull-up)
  while (digitalRead(BUTTON_PIN) == HIGH) {
    // blink led while waiting
    digitalWrite(LED_PIN, !digitalRead(LED_PIN));
    delay(100);
  }

  // debounce button
  delay(50);

  // turn on led to indicate running
  digitalWrite(LED_PIN, HIGH);

  Serial.println("starting 1000 pulses sequence...");

  // generate 1000 pulses
  for (int i = 0; i < PULSE_COUNT; i++) {
    // turn on pump
    digitalWrite(PUMP_PIN, HIGH);

    // keep on for pulse width duration
    delay(PULSE_WIDTH);

    // turn off pump
    digitalWrite(PUMP_PIN, LOW);

    // wait for remainder of period
    delay(PERIOD - PULSE_WIDTH);

    // print progress every 100 pulses
    if (i % 100 == 0) {
      Serial.print("pulses completed: ");
      Serial.println(i);
    }
  }

  // turn off led when complete
  digitalWrite(LED_PIN, LOW);

  Serial.println("sequence complete! 1000 pulses delivered.");
  Serial.println("check if you have 65ml in the measuring flask.");

  // wait for button release before allowing another cycle
  while (digitalRead(BUTTON_PIN) == LOW) {
    delay(10);
  }

  // debounce button release
  delay(50);
}