How It Works

Team Kelompok 2 IVA:

Lor Ino

•

Diaz Erlangga Al Farizi

•

14. Jannus Fransiskus Sinaga

•

Arrayan Munzi hipni

•

Gilang Wirakusuma10

•

Alghafari Muhammad Khadafi

•

mulia asih

Published June 12, 2026

Conveyor Belt Sorting System Using ATmega328P

Automated conveyor system using ATmega328P bare-metal C programming. Features IR detection, PWM speed control, and LCD monitoring.

IntermediateFull instructions provided37

Conveyor Belt Sorting System Using ATmega328P

Things used in this project

Hardware components

Microchip ATmega328

Adafruit RGB Backlight LCD - 16x2

Digilent IR Range Sensor

SparkFun Dual H-Bridge motor drivers L298

DC Motor, 12 V

Single Turn Potentiometer- 10k ohms

Solderless Breadboard Full Size

Female/Female Jumper Wires

Software apps and online services

Proteus 8 Profesional

PlatformIO IDE

Microsoft VS Code

Hand tools and fabrication machines

Soldering iron (generic)

Solder Flux, Soldering

Story

This project simulates an automated conveyor belt control system for a small-scale production line. The core challenge and primary objective of this project was to build the entire system using strict bare-metal C programming on an ATmega328P microcontroller.

As part of our Microprocessor & Microcontroller System Final Project, the use of standard Arduino functions (such as digitalWrite(), analogRead(), delay()) and external libraries (like LiquidCrystal.h) was strictly prohibited. Every hardware interaction—from driving the LCD to reading analog sensors and triggering interrupts—is handled entirely through direct register manipulation.

How It Works

The system relies on a DC motor to drive the conveyor and two Infrared (IR) obstacle sensors placed at the entry and exit points.

Initial State: The motor is stopped, and the product counters are at zero. Upon booting, the LCD displays a splash screen showing "Project Uas" and our group name, "Kelompok 2 IVA".
Product Entry (Auto-Start): When a product enters the conveyor, the first IR sensor detects it. This triggers an external interrupt that immediately starts the DC motor and increments the "In" counter.
Speed Control: While the conveyor is running, an operator can adjust the speed using a potentiometer. The microcontroller reads this analog value and converts it into a Pulse Width Modulation (PWM) signal to smoothly control the motor's speed.
Product Exit (Auto-Stop): When the product reaches the end of the line, the second IR sensor detects it. This triggers another interrupt that halts the motor instantly and increments the "Out" counter.
Real-Time Monitoring: A 16x2 LCD continuously displays the live conveyor speed (in percentage 0-100%), the motor status (RUN/STOP), and the total number of products that have entered and left.

Code

Main Code using Platform IO

#include <Arduino.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <stdbool.h>

volatile int products_entered = 0;
volatile int products_left = 0;
volatile bool motor_running = false;
volatile uint8_t current_pwm_value = 0;

void lcd_write_port(uint8_t data) {
    PORTB &= ~((1 << PB0) | (1 << PB2) | (1 << PB3) | (1 << PB4) | (1 << PB5));
    PORTC &= ~((1 << PC3) | (1 << PC4) | (1 << PC5));

    if (data & 0x01) PORTB |= (1 << PB0); // D0
    if (data & 0x02) PORTB |= (1 << PB2); // D1
    if (data & 0x04) PORTB |= (1 << PB3); // D2
    if (data & 0x08) PORTB |= (1 << PB4); // D3
    if (data & 0x10) PORTB |= (1 << PB5); // D4
    if (data & 0x20) PORTC |= (1 << PC3); // D5
    if (data & 0x40) PORTC |= (1 << PC4); // D6
    if (data & 0x80) PORTC |= (1 << PC5); // D7
}

void lcd_command(uint8_t cmd) {
    PORTD &= ~(1 << PD4); // Set RS = 0 
    lcd_write_port(cmd);  
    
    // Pulse Enable
    PORTD |= (1 << PD5); 
    _delay_us(1); 
    PORTD &= ~(1 << PD5); 

    // Clear Display dan Return
    if (cmd == 0x01 || cmd == 0x02) {
        _delay_ms(2);
    } else {
        _delay_us(100);
    }
}

void lcd_data(char data) {
    PORTD |= (1 << PD4);  // Set RS = 1 
    lcd_write_port(data); 
    
    // Pulse Enable
    PORTD |= (1 << PD5); 
    _delay_us(1); 
    PORTD &= ~(1 << PD5); 
    _delay_us(100);
}

void lcd_init() {
    DDRB |= (1 << PB0) | (1 << PB2) | (1 << PB3) | (1 << PB4) | (1 << PB5);
    DDRC |= (1 << PC3) | (1 << PC4) | (1 << PC5);
    DDRD |= (1 << PD4) | (1 << PD5); 
    
    _delay_ms(20); 
    PORTD &= ~(1 << PD4); 

    lcd_command(0x38); 
    _delay_ms(5);
    lcd_command(0x38); 
    _delay_us(15);
    lcd_command(0x38);
    lcd_command(0x0C); 
    lcd_command(0x06); 
    lcd_command(0x01); 
}

void lcd_print(const char* str) {
    while (*str) {
        lcd_data(*str++); 
    }
}

void lcd_print_num(int num) {
    char buffer[6];
    int i = 0;
    if (num == 0) {
        lcd_data('0');
        return;
    }
    while (num > 0) {
        buffer[i++] = (num % 10) + '0';
        num /= 10;
    }
    while (i > 0) {
        lcd_data(buffer[--i]);
    }
}

void lcd_set_cursor(uint8_t col, uint8_t row) {
    uint8_t row_offsets[] = {0x00, 0x40};
    lcd_command(0x80 | (col + row_offsets[row]));
}

void adc_init() {
    ADMUX = (1 << REFS0); 
    ADCSRA = (1 << ADEN) | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); 
}

uint16_t adc_read() {
    ADCSRA |= (1 << ADSC); 
    while (ADCSRA & (1 << ADSC)); 
    return ADC; 
}

void pwm_init() {
    DDRB |= (1 << PB1); // OC1A Output
    TCCR1A = (1 << COM1A1) | (1 << WGM10); // Fast PWM 8-bit
    TCCR1B = (1 << WGM12) | (1 << CS11) | (1 << CS10); // Prescaler 64
}

void motor_init() {
    DDRC |= (1 << PC1) | (1 << PC2); 
}

void interrupt_init() {
    DDRD &= ~((1 << PD2) | (1 << PD3)); 
    PORTD |= (1 << PD2) | (1 << PD3);   
    EICRA = (1 << ISC11) | (1 << ISC01);
    EIMSK = (1 << INT1) | (1 << INT0);  
}

ISR(INT0_vect) {
    products_entered++;
    motor_running = true; 
    
    PORTC |= (1 << PC1);  
    PORTC &= ~(1 << PC2); 
    OCR1A = current_pwm_value;
}

ISR(INT1_vect) {
    products_left++;
    motor_running = false; 
    
    // Matikan motor
    PORTC &= ~(1 << PC1); 
    PORTC &= ~(1 << PC2); 
    OCR1A = 0;
}

void setup() {
    lcd_init();         
    adc_init();         
    pwm_init();         
    motor_init();       
    interrupt_init();   
    sei();              

    lcd_set_cursor(0, 0);
    lcd_print("Project Uas");
    lcd_set_cursor(0, 1);
    lcd_print("Kelompok 2 IVA");
    _delay_ms(100);
    lcd_command(0x01);  
}

void loop() {
    uint16_t pot_value = adc_read();
    current_pwm_value = pot_value >> 2; 

    if (motor_running) {
        PORTC |= (1 << PC1);  
        PORTC &= ~(1 << PC2); 
        OCR1A = current_pwm_value;    
    } else {
        PORTC &= ~(1 << PC1); 
        PORTC &= ~(1 << PC2); 
        OCR1A = 0;            
    }

    uint8_t speed_percent = (current_pwm_value * 100) / 255;
    
    lcd_set_cursor(0, 0);
    lcd_print("Spd:");
    if(speed_percent < 100) lcd_print(" ");
    if(speed_percent < 10) lcd_print(" "); 
    lcd_print_num(speed_percent);
    lcd_print("% St:");
    lcd_print(motor_running ? "RUN " : "STOP");

    lcd_set_cursor(0, 1);
    lcd_print("In:");
    lcd_print_num(products_entered);
    lcd_print(" Out:");
    lcd_print_num(products_left);
    lcd_print("    ");
    
    _delay_ms(15); 
}

Conveyor Belt Sorting System Using ATmega328P