This repository contains the hardware and software for a line-following robot based on the ESP32 platform. The project was developed iteratively, starting from very simple motor-control boards and gradually evolving into a complete robot designed for further experimentation and improvement.
- Microcontroller: ESP32-S3-WROOM-1
- Motors: DC motors (up to 12 V)
- Motor Driver: TB6612FNG
- Sensors: QRD1114 reflective IR sensors
The main goal of the project is to build a reliable and understandable line-following robot while keeping the hardware and software modular and easy to modify.
The project began with simple ESP-based prototype boards whose only purpose was to verify basic motor control.
The earliest versions were essentially just ESP32 boards capable of driving DC motors, without sensors or any control algorithm. These prototypes used the L9110 motor driver and served mainly for learning how the ESP32 behaves in real hardware conditions.
Later, the project moved to a more complete design using the L293D motor driver, which made it possible to build the first fully functional robot.
These early boards established the foundation for all later hardware and software revisions.
The project went through several hardware versions. Only Revision C is actively used today; earlier versions mainly served as learning steps.
Across all hardware versions, the project consistently uses QRD1114 reflective IR sensors. Keeping the same sensor type made it easier to compare different revisions and focus on layout and software improvements instead of changing components.
Early prototype boards focused purely on motor control.
Purpose:
- Verify ESP32 motor control
- Test basic power distribution and I/O
Specifications:
- MCU: ESP32-S3-WROOM-1
- Motor driver: L9110
- Motors: Random DC motors (3–6 V)
- Sensors: Not implemented
Additional features:
- Status LED
- Programmable buttons
These versions were not complete robots, but they were crucial for early testing and experimentation.
V1.0 was the first fully functional line-following robot. All later revisions are conceptually based on this version.
Specifications:
- MCU: ESP32-S3-WROOM-1
- Motor driver: L293D
- Motors: N20, 1000 RPM, 6 V
- Sensors: QRD1114 (9×)
Additional features:
- Status LED
- Programmable buttons
- MPU-6050 socket (functional)
- Downforce fan (later abandoned after real-world testing)
This version validated the overall robot architecture and control concept.
Revision B was a design-only iteration that was never manufactured.
Planned specifications:
- MCU: ESP32-S3-WROOM-1
- Motor driver: L293D
- Motors: N20, 2000 RPM, 6 V
- Sensors: QRD1114 (9×)
Planned additional features:
- Status LED
- Programmable buttons
- MPU-6050 socket
- I2C OLED display socket
- Connector for an external master power switch
(currently shorted when not used)
This revision was scrapped because it did not provide enough benefit compared to its complexity.
Revision C is the current and actively used hardware version.
Specifications:
- MCU: ESP32-S3-WROOM-1
- Motor driver: TB6612FNG
- Motors: N20, 3000 RPM, 6–12 V
- Sensors: QRD1114 (11×)
Additional features:
- Status LED
- Programmable buttons
- MPU-6050 socket
- I2C OLED display socket
- Connector for an external master power switch
(currently shorted, prepared for competition rules)
Revision C is considered stable and serves as the final PCB platform.
- Written in Arduino-style C++ for ESP32
- Uses a PD control algorithm for line following
- Clear separation between sensor reading, control logic, and motor output
The software is structured to allow easy tuning and future feature expansion.
- Tune the PD control algorithm as much as possible
- Improve stability in turns
- Reduce oscillations
- Achieve consistent behavior on different surfaces
- Wireless communication using ESP-NOW
- Implementation of the MPU-6050
- Orientation and motion data
- Possible use for improved control or diagnostics