const int Trigger = 10; const int Echo = 11; int buzzer=7; void setup() { Serial.begin(9600); pinMode(buzzer, OUTPUT); } void loop() { long duration, cm; pinMode(Trigger, OUTPUT); digitalWrite(Trigger, LOW); delayMicroseconds(2); digitalWrite(Trigger, HIGH); delayMicroseconds(5); digitalWrite(Trigger, LOW); pinMode(Echo, INPUT); duration = pulseIn(Echo, HIGH); cm = microsecondsToCentimeters(duration); if(cm<=60) { tone(buzzer,700,90); } Serial.print(cm); Serial.print("cm"); Serial.println(); delay(1000); } long microsecondsToCentimeters(long microseconds) { return microseconds / 29 / 2; }