wet and dry waste segregation project using arduino code for science exhibition – diy – howtofunda

#include <Servo.h>

Servo myServo;

const int trigPin = 9;
const int echoPin = 8;
const int moisturePin = A0;

// Set threshold based on your moisture sensor calibration (0 – 1023)
const int moistureThreshold = 600;

void setup() {
  myServo.attach(10);
  myServo.write(90); // Neutral position (center)

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  Serial.begin(9600);
}

void loop() {
  // Clear trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Trigger ultrasonic sensor pulse
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);
  int distance = duration * 0.034 / 2; // Distance in cm

  // If object detected within 10 cm
  if (distance > 0 && distance <= 10) {
    delay(1000); // Wait for item to rest on sensor plate
    int moistureValue = analogRead(moisturePin);

    if (moistureValue < moistureThreshold) {
      // Wet Waste detected -> Rotate Servo to Wet Bin side
      myServo.write(180);
      delay(3000);
    } else {
      // Dry Waste detected -> Rotate Servo to Dry Bin side
      myServo.write(0);
      delay(3000);
    }

    // Return flap to center position
    myServo.write(90);
    delay(1000);
  }
}