/*
Eric Chut
ENGR 103
Final Assignment
*/

#define SOUND_SPEED 0.034

const unsigned long interval = 600000;  // 10 minutes in milliseconds
const unsigned long duration = 86400000;  // 24 hours in milliseconds
float distanceCm;//distance variable

void setup() {
  pinMode(5, OUTPUT);//output pin
  pinMode(18, INPUT);//input pin
  Serial.begin(115200);// baud rate
}

void loop() {
  unsigned long startTime = millis();//setting the start time variable to match the millis

  while (millis() - startTime < duration) {//24 hour timer
    unsigned long intervalStartTime = millis();

    while (millis() - intervalStartTime < interval) {//10 minute timer
      digitalWrite(5, LOW);//sending out a signal to send a sound wave
      delayMicroseconds(2);
      digitalWrite(5, HIGH);
      delayMicroseconds(10);
      digitalWrite(5, LOW);
      unsigned long pulseTime = pulseIn(18, HIGH);//records how long it takes for the signal to be bounced back
      distanceCm = (pulseTime * SOUND_SPEED)/2;//calculating the distance into centimeters
      Serial.println(distanceCm);
      if (distanceCm < 150){//alerting that something passed by the sensor
        Serial.println("something passed by");
      }
      delay(1000);  // 1 second delay between readings
    }

    // Record the end of the interval
    Serial.println("Interval ended");
    delay(1000);  // 1 second delay before starting the next interval
  }

  // The 24-hour period has ended
  Serial.println("Recording finished");
  while (true) {
    // Do nothing
  }
}