feat: complete smart dustbin embedded system with dual ultrasonic, servo lid control, 16x2 I2C LCD, alerts, and Wokwi simulation

Author: adarshsrivastav23905

.github/workflows/platformio.yml

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+name: PlatformIO Build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up PlatformIO
+        uses: n-vr/setup-platformio-action@v1
+
+      - name: Build Arduino UNO firmware
+        run: pio run

.gitignore

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+.pio/
+.vscode/
+!.vscode/extensions.json
+
+*.log
+.DS_Store
+Thumbs.db

LICENSE

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+/**
+ * ============================================================================
+ * PROJECT: Smart Dustbin – Industry-Oriented Embedded System
+ * PLATFORM: Arduino UNO / ATmega328P (Fully compatible with Wokwi / Tinkercad)
+ * AUTHOR: Adarsh Srivastav
+ * REPOSITORY: Smart-Dustbin-Embedded-System
+ * ============================================================================
+ * 
+ * DESCRIPTION:
+ * An automated, hygienic, dual-sensor smart waste management system designed
+ * for institutional and public deployment. It features:
+ * 1. Proximity-based touchless lid actuation (Ultrasonic Sensor 1 + Servo Motor).
+ * 2. Real-time internal waste level monitoring (Ultrasonic Sensor 2).
+ * 3. 16x2 I2C LCD Display telemetry output.
+ * 4. Fill-level percentage calculation and threshold detection.
+ * 5. Multi-tier alert management (Green LED, Red LED, Active Buzzer).
+ * 6. Full-bin safety interlock (prevents lid opening when bin is 100% full).
+ * 7. Non-blocking state management using millis() timers.
+ * ============================================================================
+ */
+
+#include <Arduino.h>
+#include <Servo.h>
+#include <Wire.h>
+#include <LiquidCrystal_I2C.h>
+
+// ============================================================================
+// 1. PIN DEFINITIONS & HARDWARE MAPPINGS
+// ============================================================================
+// Proximity Sensor (Hand Detection)
+const uint8_t HAND_TRIG_PIN  = 9;
+const uint8_t HAND_ECHO_PIN  = 10;
+
+// Level Sensor (Internal Bin Fill Depth)
+const uint8_t LEVEL_TRIG_PIN = 6;
+const uint8_t LEVEL_ECHO_PIN = 7;
+
+// Actuator & Acoustic Alert
+const uint8_t SERVO_PIN      = 5;
+const uint8_t BUZZER_PIN     = 4;
+
+// Visual Indicators
+const uint8_t GREEN_LED_PIN  = 12; // Normal operation / Ready
+const uint8_t RED_LED_PIN    = 13; // Full-bin warning alert
+
+// ============================================================================
+// 2. CALIBRATION CONSTANTS & SYSTEM THRESHOLDS
+// ============================================================================
+const float HAND_DETECTION_DISTANCE_CM = 20.0f;
+
+const float EMPTY_BIN_DISTANCE_CM = 30.0f;
+const float FULL_BIN_DISTANCE_CM  = 6.0f;
+
+const uint8_t FULL_LEVEL_PERCENT  = 90;
+
+const int LID_CLOSED_ANGLE = 10;
+const int LID_OPEN_ANGLE   = 100;
+
+const unsigned long HAND_SENSOR_INTERVAL_MS  = 100;
+const unsigned long LEVEL_SENSOR_INTERVAL_MS = 400;
+const unsigned long LID_HOLD_TIME_MS         = 3000;
+const unsigned long BUZZER_BEEP_INTERVAL_MS  = 2000;
+const unsigned long LCD_UPDATE_INTERVAL_MS   = 500;
+const unsigned long SERIAL_PRINT_INTERVAL_MS = 1000;
+
+// ============================================================================
+// 3. GLOBAL OBJECTS & STATE VARIABLES
+// ============================================================================
+Servo lidServo;
+LiquidCrystal_I2C lcd(0x27, 16, 2);
+
+float currentHandDistance  = -1.0f;
+float currentWasteDistance = -1.0f;
+int   currentFillPercent   = 0;
+bool  isBinFull            = false;
+bool  isLidOpen            = false;
+
+unsigned long lastHandReadTime   = 0;
+unsigned long lastLevelReadTime  = 0;
+unsigned long lidAutoCloseTarget = 0;
+unsigned long lastBuzzerBeepTime = 0;
+unsigned long lastLcdUpdateTime  = 0;
+unsigned long lastSerialLogTime  = 0;
+
+// ============================================================================
+// 4. HELPER FUNCTION: Read HC-SR04 Ultrasonic Sensor
+// ============================================================================
+float readUltrasonicDistance(uint8_t trigPin, uint8_t echoPin) {
+    digitalWrite(trigPin, LOW);
+    delayMicroseconds(2);
+
+    digitalWrite(trigPin, HIGH);
+    delayMicroseconds(10);
+    digitalWrite(trigPin, LOW);
+
+    unsigned long duration = pulseIn(echoPin, HIGH, 30000UL);
+    if (duration == 0) return -1.0f;
+
+    float distanceCm = (duration * 0.0343f) / 2.0f;
+    if (distanceCm < 2.0f || distanceCm > 400.0f) return -1.0f;
+
+    return distanceCm;
+}
+
+// ============================================================================
+// 5. HELPER FUNCTION: Calculate Bin Fill Percentage
+// ============================================================================
+int calculateFillPercentage(float distanceCm) {
+    if (distanceCm < 0.0f) return currentFillPercent;
+
+    float percentage = ((EMPTY_BIN_DISTANCE_CM - distanceCm) / 
+                        (EMPTY_BIN_DISTANCE_CM - FULL_BIN_DISTANCE_CM)) * 100.0f;
+
+    if (percentage < 0.0f) percentage = 0.0f;
+    if (percentage > 100.0f) percentage = 100.0f;
+
+    return (int)(percentage + 0.5f);
+}
+
+// ============================================================================
+// 6. ACTUATION FUNCTIONS
+// ============================================================================
+void openLid() {
+    lidServo.write(LID_OPEN_ANGLE);
+    isLidOpen = true;
+    lidAutoCloseTarget = millis() + LID_HOLD_TIME_MS;
+}
+
+void closeLid() {
+    lidServo.write(LID_CLOSED_ANGLE);
+    isLidOpen = false;
+}
+
+// ============================================================================
+// 7. ALERT MANAGEMENT FUNCTION
+// ============================================================================
+void updateAlertSystem(bool binFull) {
+    unsigned long now = millis();
+
+    if (binFull) {
+        digitalWrite(GREEN_LED_PIN, LOW);
+        digitalWrite(RED_LED_PIN, HIGH);
+
+        if (now - lastBuzzerBeepTime >= BUZZER_BEEP_INTERVAL_MS) {
+            lastBuzzerBeepTime = now;
+            digitalWrite(BUZZER_PIN, HIGH);
+            delay(100);
+            digitalWrite(BUZZER_PIN, LOW);
+        }
+    } else {
+        digitalWrite(GREEN_LED_PIN, HIGH);
+        digitalWrite(RED_LED_PIN, LOW);
+        digitalWrite(BUZZER_PIN, LOW);
+    }
+}
+
+// ============================================================================
+// 8. 16x2 LCD DISPLAY MANAGER
+// ============================================================================
+void updateLCD(unsigned long now) {
+    if (now - lastLcdUpdateTime < LCD_UPDATE_INTERVAL_MS) return;
+    lastLcdUpdateTime = now;
+
+    lcd.clear();
+
+    if (isBinFull) {
+        lcd.setCursor(0, 0);
+        lcd.print("BIN FULL! LOCK");
+        lcd.setCursor(0, 1);
+        lcd.print("FILL: ");
+        lcd.print(currentFillPercent);
+        lcd.print("% CRIT");
+    } else if (isLidOpen) {
+        lcd.setCursor(0, 0);
+        lcd.print("LID: OPENING...");
+        lcd.setCursor(0, 1);
+        lcd.print("FILL: ");
+        lcd.print(currentFillPercent);
+        lcd.print("% READY");
+    } else {
+        lcd.setCursor(0, 0);
+        lcd.print("SMART DUSTBIN");
+        lcd.setCursor(0, 1);
+        lcd.print("FILL: ");
+        lcd.print(currentFillPercent);
+        lcd.print("% NORMAL");
+    }
+}
+
+// ============================================================================
+// 9. TELEMETRY & SERIAL DIAGNOSTICS
+// ============================================================================
+void printTelemetry(unsigned long now) {
+    if (now - lastSerialLogTime >= SERIAL_PRINT_INTERVAL_MS) {
+        lastSerialLogTime = now;
+
+        Serial.print(F("[TELEMETRY] Hand: "));
+        if (currentHandDistance < 0) Serial.print(F("NONE"));
+        else { Serial.print(currentHandDistance, 1); Serial.print(F(" cm")); }
+
+        Serial.print(F(" | Waste Depth: "));
+        if (currentWasteDistance < 0) Serial.print(F("ERR"));
+        else { Serial.print(currentWasteDistance, 1); Serial.print(F(" cm")); }
+
+        Serial.print(F(" | Fill: "));
+        Serial.print(currentFillPercent);
+        Serial.print(F("% | Lid: "));
+        Serial.print(isLidOpen ? F("OPEN   ") : F("CLOSED "));
+
+        Serial.print(F(" | Status: "));
+        Serial.println(isBinFull ? F("CRITICAL (FULL)") : F("NORMAL (READY)"));
+    }
+}
+
+// ============================================================================
+// 10. SETUP FUNCTION
+// ============================================================================
+void setup() {
+    Serial.begin(9600);
+
+    pinMode(HAND_TRIG_PIN, OUTPUT);
+    pinMode(HAND_ECHO_PIN, INPUT);
+    pinMode(LEVEL_TRIG_PIN, OUTPUT);
+    pinMode(LEVEL_ECHO_PIN, INPUT);
+
+    pinMode(BUZZER_PIN, OUTPUT);
+    pinMode(GREEN_LED_PIN, OUTPUT);
+    pinMode(RED_LED_PIN, OUTPUT);
+
+    digitalWrite(BUZZER_PIN, LOW);
+    digitalWrite(GREEN_LED_PIN, HIGH);
+    digitalWrite(RED_LED_PIN, LOW);
+
+    lidServo.attach(SERVO_PIN);
+    closeLid();
+
+    // Initialize 16x2 I2C LCD
+    lcd.init();
+    lcd.backlight();
+    lcd.clear();
+    lcd.setCursor(0, 0);
+    lcd.print("SMART DUSTBIN");
+    lcd.setCursor(0, 1);
+    lcd.print("INITIALIZING...");
+    delay(1000);
+    lcd.clear();
+
+    Serial.println();
+    Serial.println(F("=========================================================="));
+    Serial.println(F("  SMART DUSTBIN - EMBEDDED SYSTEM CONTROL PLATFORM"));
+    Serial.println(F("  Architecture: Arduino UNO / ATmega328P + 16x2 I2C LCD"));
+    Serial.println(F("=========================================================="));
+    Serial.println(F("[SYS] System Initialized Successfully. Running main loop..."));
+}
+
+// ============================================================================
+// 11. MAIN SUPER-LOOP (Non-Blocking Cooperative Scheduling)
+// ============================================================================
+void loop() {
+    unsigned long now = millis();
+
+    if (now - lastHandReadTime >= HAND_SENSOR_INTERVAL_MS) {
+        lastHandReadTime = now;
+        currentHandDistance = readUltrasonicDistance(HAND_TRIG_PIN, HAND_ECHO_PIN);
+    }
+
+    if (now - lastLevelReadTime >= LEVEL_SENSOR_INTERVAL_MS) {
+        lastLevelReadTime = now;
+        currentWasteDistance = readUltrasonicDistance(LEVEL_TRIG_PIN, LEVEL_ECHO_PIN);
+        currentFillPercent = calculateFillPercentage(currentWasteDistance);
+        isBinFull = (currentFillPercent >= FULL_LEVEL_PERCENT);
+    }
+
+    if (!isBinFull) {
+        if (currentHandDistance > 0.0f && currentHandDistance <= HAND_DETECTION_DISTANCE_CM) {
+            openLid();
+        }
+    } else {
+        if (isLidOpen) {
+            closeLid();
+        }
+    }
+
+    if (isLidOpen && ((long)(now - lidAutoCloseTarget) >= 0)) {
+        closeLid();
+    }
+
+    updateAlertSystem(isBinFull);
+    updateLCD(now);
+    printTelemetry(now);
+}

README.md

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+# System Architecture
+
+```text
+                    USER
+                     |
+                     v
+             +---------------+
+             | Hand Sensor   |
+             | HC-SR04       |
+             +-------+-------+
+                     |
+                     v
+              +-------------+
+              | Arduino UNO |
+              | Control     |
+              | Logic       |
+              +------+------+ 
+                     |
+          +----------+----------+
+          |          |          |
+          v          v          v
+       Servo      Level       Alert
+       Control    Sensor      System
+          |          |          |
+          v          v      +---+---+
+        Lid       Fill %    LED   Buzzer

arduino_code/smart_dustbin.ino

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+# Pin Configuration
+
+| Component | Signal | Arduino Pin |
+|---|---|---|
+| Hand HC-SR04 | TRIG | D9 |
+| Hand HC-SR04 | ECHO | D10 |
+| Level HC-SR04 | TRIG | D6 |
+| Level HC-SR04 | ECHO | D7 |
+| Servo | PWM | D5 |
+| Buzzer | Signal | D4 |
+| Green LED | Anode | D12 |
+| Red LED | Anode | D13 |