const int trigPin=5;
const int echoPin=18;
const int nene=33;

#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;

void setup(){
 Serial.begin(115200);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
pinMode(nene, OUTPUT);
}

void loop(){
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin,HIGH);
distanceCm = duration * SOUND_SPEED/2;
distanceInch = distanceCm * CM_TO_INCH;

Serial.print("Distance(cm): ");
Serial.println(distanceCm);
Serial.print("Distance(inch): ");
Serial.println(distanceInch);

if(distanceInch>=100){
digitalWrite(nene, HIGH);
delay(3000);
digitalWrite(nene, LOW);

}

delay(1000);

}