/********* Car Bumper Sensor ******/

// Pins
const int TRIG_PIN = 4;
const int ECHO_PIN = 1;
int RED = 13;
int GREEN = 7;
int BUZZER = 8;

// Anything over 400 cm (23200 us pulse) is "out of range"
const unsigned int MAX_DIST = 232000;

void setup() {

 Serial.begin(115200);
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);


}

float readDistanceCM ()
{
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN,HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration *0.034 / 2;

}

void loop() {

  float distance = readDistanceCM();
  bool isNOTNearby = distance > 100; 
  bool isNearby = distance < 100;
  digitalWrite(GREEN, isNOTNearby);
  digitalWrite(RED, isNearby);
  digitalWrite(BUZZER, isNearby);

  Serial.print ("Measured distance: ");
  Serial.println(readDistanceCM());

  delay(100);
}