Week 8 Assignment

Ultrasonic Distance-Based LED Switch

Concept: This project uses an HC-SR04 ultrasonic sensor and an Arduino to activate an LED when an object is within 10 cm. This distance-based switch can serve as a touchless light control.

Materials
– Arduino Uno
– HC-SR04 Ultrasonic Sensor
– LED
– 220Ω Resistor
– Breadboard and Jumper Wires

Process:
1. Setup: The ultrasonic sensor’s Trig and Echo pins connect to Digital Pins 12 and 13 on the Arduino, while the LED is connected to Digital Pin 2 with a resistor.
2. Code: The Arduino reads the distance from the sensor. If within 10 cm, it lights the LED; otherwise, it turns off.
3. Testing: The LED successfully turns on when an object is close, providing feedback on proximity.

CODE: 

const int echo = 13;     // Echo pin of the ultrasonic sensor
const int trig = 12;     // Trigger pin of the ultrasonic sensor
int LED = 2;             // LED pin

int duration = 0;        // Variable to store pulse duration
int distance = 0;        // Variable to store calculated distance

void setup() {
  pinMode(trig, OUTPUT);    // Set trig pin as output
  pinMode(echo, INPUT);     // Set echo pin as input
  pinMode(LED, OUTPUT);     // Set LED pin as output
  Serial.begin(9600);       // Initialize serial monitor for debugging
}

void loop() {
  // Send out a 10 microsecond pulse on the trig pin
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  // Read the echo pin and calculate distance
  duration = pulseIn(echo, HIGH);
  distance = (duration / 2) / 29.1;  // Convert duration to distance in cm

  // Turn on the LED if the distance is less than 10 cm
  if (distance < 10 && distance > 0) {  // Check distance within range
    digitalWrite(LED, HIGH);  // Turn on LED
  } else {
    digitalWrite(LED, LOW);   // Turn off LED
  }

  // Print distance to the serial monitor for debugging
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(500);  // Delay for stability
}

VIDEO DEMONSTRATION

 

 

Reflection: This project demonstrates basic sensor integration and is adaptable for touchless applications in home automation.