Line Follower

🤖 ESP32 Line Follower Robot — Hardware Design

A compact and efficient line follower robot built using the ESP32

Demo

This project showcases the schematic and PCB design of a reliable line follower robot capable of high-speed tracking with stable power delivery and clean motor control. It is designed as a practical exploration of real-world embedded hardware development and PCB design workflows.

📂 Repository Structure

PID-Line-Follower
│
├── Firmware
│   └── Arduino_Code
│
├── Hardware
│   ├── Images
│   ├── Schematic
│   ├── Datasheet
│   └── Pin_Mapping
│
├── README.md
└── .gitignore

Working Principle

• The ESP32 DevKit (38-pin) acts as the main controller.
• An 8-channel IR sensor array detects the line:
  • 6 sensors operate in analog mode for precise position tracking.
  • 2 sensors operate in digital mode for edge detection.
• The TB6612FNG motor driver controls two DC motors with efficient PWM-based speed regulation.
• A LM2596 buck converter steps down the battery voltage to provide a stable 3.3V rail for the ESP32 and logic circuitry.
• Two push buttons allow:
  • Calibration mode – tune sensor thresholds.
  • Mode selection – switch between operating behaviors.
• Decoupling capacitors and a ground plane ensure noise reduction and power stability.

🎯 Objective

To design and develop a robust hardware platform for a line follower robot that demonstrates:

• Proper power architecture
• Motor driver integration
• Mixed analog/digital sensing
• Clean PCB layout practices
• Expandable embedded design

Hardware Overview

Power Architecture

Battery → Slide Switch → LM2596 Buck → 3.3V Rail

Design considerations:

✅ Wide power traces for motor current
✅ Dedicated ground plane
✅ Local decoupling near driver and ESP32
✅ Separate motor and logic routing where possible

Firmware

The robot firmware is written for the ESP32 using the Arduino framework.

Key features of the control software:

• Multi-sensor line detection
• Adaptive speed control
• PID-based steering correction
• Calibration routines for sensor tuning

Firmware source code is available in the Firmware directory.

📷 Preview

🖼️ Schematic

📐 PCB Layout

🧊 3D View

Key Features

✅ Stable buck-regulated power supply
✅ High-efficiency TB6612FNG motor control
✅ Mixed analog + digital sensor interface
✅ Compact 2-layer PCB
✅ Ground plane for noise reduction
✅ Designed following practical PCB routing guidelines

Design Notes

• Motor traces are sized to handle higher current.
• Ground return paths are optimized using copper pour.
• Mounting holes are included for chassis integration.
• Connectors are placed for easy wiring and maintenance.

Future Improvements

• PID tuning for smoother tracking
• Encoder-based speed feedback
• Bluetooth / Wi-Fi telemetry
• Battery voltage monitoring
• On-board charging circuit
• Custom buck stage instead of module
• Fully integrated motor + sensor board

📚 Learning Outcomes

This project helped strengthen understanding of:

• Power electronics in embedded systems
• PCB stackup and routing
• Grounding strategies
• Motor driver layout considerations
• Hardware debugging practices