6.Ultrasonic with Led and Buzzer

Ultrasonic with Led and Buzzer

Materials Needed:

• Arduino board
• Ultrasonic sensor (e.g., HC-SR04)
• LED (any color)
• 220Ω resistor for LED
• 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. LED to Arduino:

   • Connect the anode (longer leg) of the LED to Pin 13 through a 220Ω resistor.
   • Connect the cathode (shorter leg) to GND.

3. Buzzer to Arduino:

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

Procedure:

1. Connect the Components:

   • Use jumper wires to connect the ultrasonic sensor, LED, and buzzer as described above.

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 ledPin = 13;

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(ledPin, OUTPUT);

  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 LED and buzzer if the object is closer than the threshold distance

  if (distance <= thresholdDistance) {

    digitalWrite(ledPin, HIGH);

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

  } else {

    digitalWrite(ledPin, LOW);

    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 LED and Buzzer Behavior:

   • The LED will light up, and 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, both the LED and buzzer will turn off.

Explanation:

• The TRIG pin sends a pulse to start measuring distance.
• The ECHO pin receives the reflected pulse, and the time taken is used to calculate the distance.
• The LED is turned on and the buzzer is activated if the measured distance is less than or equal to the specified threshold (thresholdDistance).
• The tone function (tone(buzzerPin, 1000)) generates a sound at 1kHz when the distance condition is met, and the noTone function turns it off.