5.Ultrasonic Obstacle Detection with Buzzer

 Ultrasonic Obstacle Detection with Buzzer

Materials Needed:

• Arduino board
• Ultrasonic sensor (e.g., HC-SR04)
• Buzzer
• Jumper wires
• Breadboard (optional)

Connections:

1. Ultrasonic Sensor to Arduino:

• TRIG pin → Pin 9
• ECHO pin → Pin 10
• VCC pin → 5V
• GND pin → GND

2. Buzzer to Arduino:

   • Connect one terminal of the buzzer to Pin 11.
   • Connect the other terminal to GND.

Procedure:

1. Connect the Ultrasonic Sensor and Buzzer:

   • Use jumper wires to connect the ultrasonic sensor as described above.
   • Connect the buzzer to Pin 11 and GND.

2. Write the Arduino Code:

• Copy and paste the following code into the Arduino IDE:

C++ Code

const int trigPin = 9;

const int echoPin = 10;

const int buzzerPin = 11;

int thresholdDistance = 20;  // Set the distance threshold in centimeters

void setup() {

  Serial.begin(9600);  // Start the serial communication at 9600 baud rate

  pinMode(trigPin, OUTPUT);

  pinMode(echoPin, INPUT);

  pinMode(buzzerPin, OUTPUT);

}

void loop() {

  long duration;

  int distance;

  // Send a 10us pulse to trigger the sensor

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  // Measure the duration of the pulse on the echo pin

  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in centimeters

  distance = duration * 0.034 / 2;

  // Print the distance to the serial monitor

  Serial.print("Distance: ");

  Serial.print(distance);

  Serial.println(" cm");

  // Turn on the buzzer if the object is closer than the threshold distance

  if (distance <= thresholdDistance) {

    tone(buzzerPin, 1000);  // Emit a 1kHz sound

  } else {

    noTone(buzzerPin);  // Turn off the buzzer

  }

  delay(500);  // Wait for a short while before the next measurement

}

1. Upload the Code:

   • Connect your Arduino to the computer and upload the code using the Arduino IDE.

2. Open the Serial Monitor:

   • Open the Serial Monitor to see the distance readings. Ensure the baud rate is set to 9600.

3. Observe Buzzer Behavior:

   • The buzzer will emit a sound when an object is closer than 20 cm (you can adjust the thresholdDistance value to change the threshold).
   • When the object is beyond that distance, the buzzer will turn off.

Explanation:

The TRIG pin is used to send a pulse to initiate distance measurement.

The ECHO pin receives the reflected pulse, and the time taken is used to calculate the distance.

The buzzer is controlled by Pin 11 and emits a 1kHz tone when the object is within the threshold distance.

The tone function (tone(buzzerPin, 1000)) generates the sound, and the noTone(buzzerPin) function turns it off.