Make a touchless Doorbell | Using arduino uno with ultrasonic sensor | Plugin Electronics 

Code: const int trigPin = 4; const int echoPin = 5; const int buzzerPin = 8; void setup() { pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); pinMode(buzzerPin, OUTPUT); } void loop() { digitalWrite(trigPin, LOW); delayMicroseconds(5); digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); int duration = pulseIn(echoPin, HIGH); delay(50); int distance = duration / 29.1; if (distance < 20) { digitalWrite(buzzerPin, HIGH); } else { digitalWrite(buzzerPin, LOW); } }

Thanks for the help

thank u soo much sir!!!!!! this worked for me on the very first try. please upload other projects like this. thank you once again !!!!!!

bro is there any poerfull buzzer to provide the sound more efficient and sufficient? IF there is suggest me one! BTW nice vid

Pulsein was not declared in this scope this error come program

Hello sir plz upload circuit diagram of it

Bro ur cheat Its not working Its play automatically within 5 sec