#define PIN_RED 2     // The Arduino pin connected to R pin of traffic light module
#define PIN_YELLOW 3  // The Arduino pin connected to Y pin of traffic light module
#define PIN_GREEN 4   // The Arduino pin connected to G pin of traffic light module

//#define RED_TIME 2000     // RED time in millisecond
#define YELLOW_TIME 1000  // YELLOW time in millisecond
//#define GREEN_TIME 2000   // GREEN time in millisecond

#define RED    1  // Index in array
#define YELLOW 0  // Index in array
#define GREEN  2  // Index in array

const int pins[] = { PIN_YELLOW, PIN_GREEN, PIN_RED  };

const int times = YELLOW_TIME ;
const int inputPin = 5;
unsigned long last_time = 0;
int light = GREEN;  // start with RED light
int pirState; // we start, assuming no motion detected
int val = 0; // variable for reading the pin status
int minimummSecsLowForInactive = 5000; // If the sensor reports low for
// more than this time, then assume no activity
long unsigned int timeLow;
long unsigned int RED_TIME;
long unsigned int GREEN_TIME;
boolean takeLowTime;

void setup() {
  Serial.begin(9600);
  pinMode(PIN_RED, OUTPUT);
  pinMode(PIN_YELLOW, OUTPUT);
  pinMode(PIN_GREEN, OUTPUT);
  pinMode(inputPin, INPUT); // declare sensor as input
  trafic_light_on(light);
  
}

// loop the PIR sensor detection
void loop() {

  val = digitalRead(inputPin); // read input value
  if (val == HIGH) { // check if the input is HIGH
    
    if (pirState) {
    int light = YELLOW;// start with yellow
    trafic_light_on(light);
    if ((millis() - last_time) > times) { //wait for yellow 1s
    light++;//turn to redlight

    trafic_light_on(light);
          
    Serial.println("People Detection!");
    delay(50);
     // turn to red
     pirState = false;
    }
    RED_TIME = false;// start red time
   }
  }
   
  
      
  else {
     
    if (RED_TIME){
     timeLow = millis(); 
     RED_TIME = false;
    }
 
    if(!pirState && millis() - timeLow > minimummSecsLowForInactive)
    // in red light and wait until over 5s 
    {
     pirState = true;// change back to original state to detect
     int light = GREEN;
     trafic_light_on(light);
     Serial.print("People Pass Safely!") ;  
     delay(50);
     last_time = millis();
     
    }
  }
}
  
void trafic_light_on(int light) {
  if (light == RED){ 
  // red light on
  digitalWrite(PIN_RED, HIGH);   // turn on
  digitalWrite(PIN_YELLOW, LOW); // turn off
  digitalWrite(PIN_GREEN, LOW);  // turn off
  delay(RED_TIME); // keep red light on during a period of time
  }
  else if(light == YELLOW){
  // yellow light on
  digitalWrite(PIN_RED, LOW);    // turn off
  digitalWrite(PIN_YELLOW, HIGH); // turn on
  digitalWrite(PIN_GREEN, LOW); // turn off
  delay(YELLOW_TIME); // keep yellow light on during a period of time
  }
  else if(light == GREEN){
  // green light on
  digitalWrite(PIN_RED, LOW);    // turn off
  digitalWrite(PIN_YELLOW, LOW); // turn off
  digitalWrite(PIN_GREEN, HIGH); // turn on
  delay(GREEN_TIME); // keep green light on during a period of time
  }
}