Line Following & Object Avoidance Robot

Project for ECE357, Shiv Nadar University

Overview

This project implements an autonomous mobile robot in Embedded C capable of following a predefined line, detecting obstacles, and executing avoidance maneuvers. The system demonstrates real-time control, sensor integration, and modular software architecture on an Arduino platform.

Academic Context

• Course: ECE357 – Embedded Systems and Applications
• Institution: Shiv Nadar University
• Objective: Apply principles of embedded programming, sensor fusion, and control logic to design a reliable line-following and obstacle-avoiding robot.

Core Functionality

1. Line Tracking

   • Uses an infrared sensor array (2- or 3-channel) to detect and follow black tape on the ground.

2. Obstacle Detection

   • Employs an HC-SR04 ultrasonic sensor for distance measurements up to 4 meters.

3. Collision Avoidance

   • Implements decision logic to stop, change direction, and resume line tracking when an obstacle is within a predefined threshold.

4. Real-Time Control

   • Executes a continuous control loop (while(1)) in Embedded C to achieve sub-millisecond response times.

Hardware Components

Component	Specification / Notes
Arduino Uno (or equivalent)	Provides control logic and I/O interfaces.
IR Line Sensor Array	2- or 3-channel module for robust edge detection.
HC-SR04 Ultrasonic Sensor	Ultrasonic rangefinder for obstacle detection.
DC Motors with Wheels (×4)	Rear motors daisy-chained to front for synchronized movement.
Power Supply (Battery Pack)	7.4 V LiPo recommended to separate logic and motor power.
Chassis Kit	Adjustable frame for sensor and component mounting.

Design Note: Although the Arduino was capable of directly driving the motors, it is strongly recommended to use a dedicated motor driver (e.g., L298N) and an independent power source for the motors. This configuration prevents voltage drops and protects the microcontroller from brownouts.

Software Architecture

• Language: Embedded C (Arduino-compatible)
• Structure: Modular design with separate files for sensing, actuation, and control logic.
• Main Loop: Implements the sequence “sense → decide → act” with minimal overhead.

Module Breakdown

Module	Description
line_tracker.c	Reads IR sensors, computes deviation from line.
ultrasonic.c	Triggers ultrasonic pulses, measures echo time.
motor_ctrl.c	Generates PWM signals, controls motor direction.
main.c	Initializes hardware, manages the control loop.

Behavior Flowchart

flowchart TD
  Start --> CheckLine
  CheckLine{Line Detected?}
  CheckLine -- Yes --> CheckObstacle
  CheckLine -- No --> RecoveryMode
  CheckObstacle{Obstacle Within Threshold?}
  CheckObstacle -- No --> MoveForward
  CheckObstacle -- Yes --> AvoidObstacle
  RecoveryMode --> Start
  MoveForward --> Start
  AvoidObstacle --> Start

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