const int Trigger = 32;
const int Echo    = 34;
const int Buzzer  = 14;
const int LEDR = 13;
const int LEDY = 25;
const int LEDG = 26;


#define SOUND_SPEED 0.034

long duration;
float distanceCm;


void setup() 
{
  pinMode (LEDR     ,OUTPUT) ;
  pinMode (LEDY     ,OUTPUT) ;
  pinMode (LEDG     ,OUTPUT) ;
  pinMode (Trigger ,OUTPUT);
  pinMode (Echo    , INPUT);
  pinMode (Buzzer  ,OUTPUT);
  Serial.begin(115200);
}

void loop() 
{
  digitalWrite(Trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(Trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(Trigger, LOW);
  duration = pulseIn(Echo, HIGH);
  distanceCm = duration*SOUND_SPEED/2;
  Serial.print("PEDESTRIAN CROSSSING !!! ");
  //Serial.print(distanceCm);
  //Serial.println("cm");
  
  if (distanceCm < 5) 
  {
    digitalWrite(Buzzer, HIGH);
    delay(50);
    digitalWrite(Buzzer, LOW);
    digitalWrite(LEDG, HIGH);
    delay(50);
    digitalWrite(LEDG, LOW);
    
  }
  else if (distanceCm < 10)
  {
    digitalWrite(Buzzer, HIGH);
    delay(100);
    digitalWrite(Buzzer, LOW);
    digitalWrite(LEDG, HIGH);
    delay(100);
    digitalWrite(LEDG, LOW);
    
  }
  
  else if (distanceCm < 15)
  {
    digitalWrite(Buzzer, HIGH);
    delay(200);
    digitalWrite(Buzzer, LOW);
    digitalWrite(LEDG, HIGH);
    delay(200);
    digitalWrite(LEDG, LOW);
  }
  
  else if (distanceCm < 20)
  {
    digitalWrite(Buzzer, HIGH);
    delay(500);
    digitalWrite(Buzzer, LOW);
    digitalWrite(LEDG, HIGH);
    delay(500);
    digitalWrite(LEDG, LOW);
  }
  
  delay(100);

}