An ultrasonic sensor is an instrument that measures the distance to an object using ultrasonic sound waves.
An ultrasonic sensor uses a transducer to send and receive ultrasonic pulses that relay back information about an object’s proximity.
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// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
// defines variables
long duration;
long distance;
void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
Serial.begin(9600); // Starts the serial communication
}
void loop() {
// 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;
Serial.print(distance);
Serial.println(" CM ");
}