Ultrasonic light

/*
HC-SR05 pin   Arduino pin   Relay Board     Light      Plug
  vcc           5V             X            x          x
  Trig         pin 9           X            x          x
  Echo         pin 8           X            x          x
  Gnd          Gnd             Gnd          x          x
   X           pin 12         signal pin    x          x
   X           Vin            +V            x          x
   x           x               NO           com        x
   x           x               x            Gnd        Gnd
   x           x              Com           x          Com         
*/
int s;
int state=0; 
void setup() {
  // initialize serial communication:
  Serial.begin(9600);
   pinMode(8, INPUT);
   pinMode(9, OUTPUT);
   pinMode(12, OUTPUT);  
   digitalWrite(9, LOW);
   digitalWrite(8, LOW);
}

void loop() {
  
  long duration, inches, cm;

  

    digitalWrite(9, HIGH);
    delayMicroseconds(5);
    digitalWrite(9, LOW);
    delayMicroseconds(5);
 
 
  duration = pulseIn(8, HIGH);

  
  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);

  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();

 
  if(inches<12){  //   change number too increase/decrease sensor range
 digitalWrite(12, HIGH);
    delay(10000);//change number for how long kight stays on mil sec
    }else{
    digitalWrite(12, LOW);//change number too change off state distance
      }

   delay(100);
}

long microsecondsToInches(long microseconds) {
 
  return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds) {
 
  return microseconds / 29 / 2;
}