STM32 Enhanced Line Follower Robot

Overview

This project is a high-performance line follower robot firmware designed for the STM32F103C8T6 (Blue Pill) microcontroller. It features an advanced navigation system capable of handling multiple complex zones, including:

• Black Box: Initial blind navigation.
• Curved Sections: Smooth PID control for sinuous lines.
• Hexagon Zone: Logic for navigating complex polygonal paths.
• Checkerboard: Handling discontinuous lines.
• Brain/Color Zone: Special logic for color inversion or specific tasks.

The system uses a 6-channel IR sensor array for line detection and an H-Bridge motor driver for differential drive control.

Hardware Requirements

• Microcontroller: STM32F103C8T6 (Blue Pill)
• Motor Driver: L298N, TB6612FNG, or similar H-Bridge driver.
• Sensors: 6-Channel Analog IR Line Sensor Array (e.g., QTR-8A or generic).
• Chassis: Differential drive robot chassis.
• Power: LiPo battery (2S or 3S recommended).

Wiring & Pinout

Motor Connections

Based on Core/Inc/motor_control.h:

Function	STM32 Pin	Timer/Channel	Description
Left Motor PWM	PB6	TIM4 CH1	Speed control for Left Motor
Left Motor Dir	PA4	GPIO Output	Direction for Left Motor
Right Motor PWM	PB7	TIM4 CH2	Speed control for Right Motor
Right Motor Dir	PA5	GPIO Output	Direction for Right Motor

Note: Ensure your motor driver supports PWM+Direction control. If using L298N with IN1/IN2/EN pins, connect PWM to EN and Direction to IN1 (with IN2 inverted via hardware or code modification).

Sensor Connections

The system expects 6 Analog Sensors. Current Configuration Note: The generated main.c currently initializes ADC1 on PA0. You must configure the remaining ADC channels in STM32CubeMX or main.c to match your hardware (typically PA0-PA3, PA6-PA7, avoiding the motor pins PA4/PA5).

Sensor Index	Recommended Pin	Description
Sensor 0 (Left)	PA0	ADC1 Channel 0
Sensor 1	PA1	ADC1 Channel 1
Sensor 2	PA2	ADC1 Channel 2
Sensor 3	PA3	ADC1 Channel 3
Sensor 4	PA6	ADC1 Channel 6
Sensor 5 (Right)	PA7	ADC1 Channel 7

Other Peripherals

• LED: PC13 (On-board LED) - Used for calibration status.
• Debug/Aux: PA8, PA9, PA10, PA11 are configured as outputs (usage defined in user code).

Software Architecture

Core Files

• Core/Src/enhanced_line_follower_fixed.c: The main entry point and control loop. Replaces the standard main.c logic.
• Core/Inc/motor_control.h: Motor control logic and pin definitions.
• Core/Src/sensor_processing.c: Sensor data normalization, calibration, and line position calculation.
• Core/Src/calibration.c: Routines for calibrating sensor min/max values.

Zone Logic

The robot uses a state machine to switch between different navigation strategies:

1. Calibration: On startup, the robot calibrates sensors (rotate over line).
2. Black Box: Blind acceleration.
3. Line Follow: PID control based on weighted average of sensor inputs.
4. Special Zones: Detected via specific sensor patterns (e.g., all white, all black, specific widths).

How to Build and Flash

1. Open in STM32CubeIDE:

   • Select File > Open Projects from File System...
   • Point to the project directory.

2. Configuration:

   • Open final test i hope.ioc if you need to change pin assignments using CubeMX. Warning: Regenerating code might overwrite manual changes in main.c.

3. Build:

   • Click the "Hammer" icon or Project > Build Project.

4. Flash:

   • Connect ST-Link V2.
   • Click "Run" or "Debug".

Calibration

On startup, the robot expects to be placed on the line. It may perform a calibration sequence (spinning left/right) to learn the white/black values. Ensure the LED (PC13) indicates the calibration state.

Credits

Strategy analysis and zone logic based on robot_strategy.md.