/*
-------------------------------------------------------------------------
Car Parking System

Create by: aruna devi

Ig: aruna.com
Github: aruz
-------------------------------------------------------------------------
*/

#define echoPin 3 // Echo Pin
#define trigPin 2 // Trigger Pin
#define LEDPin 13 // Onboard LED
int LED_EMPTY = 6;
int LED_FULL = 7;
int LED_PENDING = 8;
int BUZZER = 4;

void ULT(void);
long myChannelNumber ="2652840";//thingspeak channel number
const char * myWriteAPIKey = "K1212PF176LLRKYR"; //thingspeak mywrite_apikey
char ssid[] = "Wokwi-GUEST"; //wifi id
char pass[] = ""; //wifi password
int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
  Serial.begin (115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
  pinMode(LED_EMPTY, OUTPUT);
  pinMode(LED_FULL, OUTPUT);
  pinMode(LED_PENDING, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() {
  ULT();
  Serial.println(distance);  //show distance

  /*vacant, out green light*/
  if(distance >= 100){
    digitalWrite(LED_EMPTY,1);
    digitalWrite(LED_PENDING,0);
    digitalWrite(LED_FULL,0);
    Serial.println("Empty Space.");
  }

  /*someone is parking, out yelow light*/
  else if(distance < 100 && distance >= 30){
    digitalWrite(LED_EMPTY,0);
    digitalWrite(LED_PENDING,1);
    digitalWrite(LED_FULL,0);
    tone(BUZZER, 800);
    delay(400);
    digitalWrite(LED_EMPTY,0);
    digitalWrite(LED_PENDING,0);
    digitalWrite(LED_FULL,0);
    noTone(BUZZER);
    delay(300);
    Serial.println("Car is going to park here or going out.");
  }

  /*occupied, out red light*/
    else{
    digitalWrite(LED_EMPTY,0);
    digitalWrite(LED_PENDING,0);
    digitalWrite(LED_FULL,1);
    Serial.println("Car is Parking.");
  }

}
ThingSpeak.setField(3,distance);

void ULT(){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);

  //Calculate the distance (in cm) based on the speed of sound.
  distance = duration / 58.2;
}