// defines pins numbers const int trigPin = 9; const int echoPin = 10; const int buzzer = 6; // defines variables long duration; int distance; int safetyDistance; void setup() { pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output pinMode(echoPin, INPUT); // Sets the echoPin as an Input pinMode(buzzer, OUTPUT); safetyDistance = ultrasonic(); Serial.begin(9600); // Starts the serial communication } void loop() { int dist = ultrasonic(); if (dist <= safetyDistance){ tone(buzzer, 2500); delay(500); tone (buzzer, 2500); } else{ noTone (buzzer); } // Prints the distance on the Serial Monitor Serial.print("Distance: "); Serial.println(dist); } int ultrasonic(){ // Clears the trigPin digitalWrite(trigPin, LOW); delayMicroseconds(2); // Sets the trigPin on HIGH state for 10 micro seconds digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); // Reads the echoPin, returns the sound wave travel time in microseconds duration = pulseIn(echoPin, HIGH); // Calculating the distance distance= duration*0.034/2; return distance; }