Smart Waste Segregator (Dry & Wet Dustbin)

Introduction

Separating wet and dry trash is crucial for recycling, but it’s a messy job. In this advanced Plzpapa Robotic Kit project, we build an Automatic Waste Segregator equipped with a sensitive Water Level Sensor. This smart bin can detect even small traces of liquid or moisture in the trash and automatically sorts it into the correct compartment.

How It Works: 

This intelligent system uses a two-step verification process:

1. Object Detection: An Ultrasonic Sensor acts as a proximity detector, waking up the system when waste is thrown in.
2. Liquid Analysis: The waste lands on a Water Level Sensor plate.
   1. Conductivity Check: The sensor measures the conductivity of the object. Since wet items (like fruit peels or tea bags) conduct electricity better than dry items (like paper or plastic), the sensor sends a signal to the Arduino.
   2. Auto-Sorting: If liquid is detected, the Servo Motor directs the waste to the Wet Bin. If the object is dry, it is sorted into the Dry Bin.

Key Features:

• High Sensitivity: Detects water, juice, or moisture instantly using the Water Level Sensor.
• Hands-Free Sorting: Fully automated process powered by Arduino.
• Servo Mechanism: Precise 180-degree motor control for accurate separation.
• Eco-Friendly: Encourages proper waste disposal habits in children and adults alike.

Components Required

To build this Smart Waste Segregator (Dry & Wet Dustbin) with Plzpapa Robotic Kit, we used the following parts from the Plzpapa Basic Robotic Kit:

• Arduino Uno
• Ultrasonic Sensor
• Servo Motor
• Water Level Sensor

Wiring (Taarein Jorna)

1. Ultrasonic Sensor:

• [VCC]  to 5V
• [Trig] to Pin8
• [ECHO] to Pin9
• [GND] to GND

2. Servo Motor

• Brown Wire to GND
• Red Wire to 5V
• Orange Wire to Arduino Pin 7

3. Water Level Sensor

• Water Sensor (+) : Arduino 5V
• Water Sensor (-) : Arduino GND
• Water Sensor (S) : Arduino Pin A0 (Signal Pin)

Code

#include <Servo.h>

Servo myservo;

// --- PINS ---
const int trigPin = 8;
const int echoPin = 9;
const int waterSensorPin = A0; // Water Level Sensor Pin

// --- SETTINGS ---
// Water Sensor ki reading 0 se shuru hoti hai.
// Agar kachra geela hoga to reading 100-300 se upar jaye gi.
// Hum ne '100' threshold rakha hai (Isay adjust kar saktay hain).
int wetThreshold = 100;   

int Ultra_Distance = 15; // 15cm range

// Variables
long duration;
int distance = 0;
int waterValue = 0;

void setup() {
  Serial.begin(9600);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  myservo.attach(7);
  myservo.write(90); // Normal Position (Middle)
  
  Serial.println("System Ready: Water Sensor Mode");
}

void loop() {
  // 1. Ultrasonic Distance Check
  distance = 0;
  for(int i=0; i<2; i++) {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(7);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    
    duration = pulseIn(echoPin, HIGH);
    distance = (duration * 0.034 / 2) + distance;
    delay(10);
  }
  distance = distance / 2;

  // 2. Agar Kachra Aya (15cm se qareeb)
  if (distance < Ultra_Distance && distance > 1) {
    Serial.println("Waste Detected! Checking for Liquid...");
    delay(1500); // Thora wait taake kachra sensor par sahi se gir jaye
    
    // 3. Water Sensor Reading Check
    waterValue = 0;
    // Hum 3 dafa check karein ge taake ghalti na ho
    for(int i=0; i<3; i++) {
      waterValue = waterValue + analogRead(waterSensorPin);
      delay(50);
    }
    waterValue = waterValue / 3; // Average reading

    Serial.print("Water Level Reading: ");
    Serial.println(waterValue);

    // 4. Decision (Faisla)
    if (waterValue > wetThreshold) {
      // --- WET WASTE (Right Side) ---
      Serial.println("==> LIQUID Detected (Wet Waste)");
      myservo.write(10);  // Right Side
      delay(3000);
    } 
    else {
      // --- DRY WASTE (Left Side) ---
      Serial.println("==> NO Liquid (Dry Waste)");
      myservo.write(170); // Left Side
      delay(3000);
    }
    
    // 5. Reset
    myservo.write(90);
    distance = 0;
    waterValue = 0;
    delay(1000);
  }
}