Proximity Sensor Arduino - Sample Code

The project video: https://www.youtube.com/watch?v=yBHyAFmtH-E&feature=youtu.be

const int greenLightPin = 6;
const int yellowLightPin = 5;
const int redLightPin = 4;

const int ussTrigPin = 2;
const int ussEchoPin = 3;

void setup() {
  // put your setup code here, to run once:
  pinMode(greenLightPin,OUTPUT);
  pinMode(yellowLightPin,OUTPUT);
  pinMode(redLightPin,OUTPUT);

  pinMode(ussTrigPin,OUTPUT);
  pinMode(ussEchoPin,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  long duration, inches;
  digitalWrite(ussTrigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(ussTrigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(ussTrigPin, LOW);
  pinMode(ussEchoPin, INPUT);
  duration = pulseIn(ussEchoPin, HIGH);
  inches = microsecondsToInches(duration);
  if(inches > 10 && inches < 15){
    digitalWrite(greenLightPin, HIGH);
    delay(100);
    digitalWrite(greenLightPin, LOW);
    delay(100);
  }
  if(inches < 10 && inches > 5){
    digitalWrite(yellowLightPin, HIGH);
    delay(100);
    digitalWrite(yellowLightPin, LOW);
    delay(100);
  }
  if(inches < 5){
    digitalWrite(redLightPin, HIGH);
    delay(100);
    digitalWrite(redLightPin, LOW);
    delay(100);
  }
  
}
long microsecondsToInches(long microseconds)
{
  return microseconds / 74 / 2;
}