🤖 Pixel — STM32 Autonomous Robot

Pixel is a real-time embedded robotics project built on the STM32 Nucleo-F401RE.
It autonomously navigates its environment using ultrasonic sensing and PWM-based motor control.

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🚀 Overview

This project implements a differential-drive robot that:

• detects obstacles using an ultrasonic sensor (HC-SR04)
• processes sensor data on an STM32 microcontroller
• generates real-time PWM signals to control motor speed
• executes autonomous navigation logic

The goal is to demonstrate embedded systems design, real-time control, and hardware-software integration.

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🧠 System Architecture

Ultrasonic Sensor → STM32 Nucleo-F401RE → L298N Motor Driver → Motors ↑ Battery

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⚙️ Key Features

• Modular firmware design (motors, ultrasonic, control loop)
• PWM-based motor speed control using STM32 timers
• Real-time distance measurement with ultrasonic sensing
• Autonomous obstacle avoidance behavior
• Clean separation between hardware and software components

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🧰 Hardware

• STM32 Nucleo-F401RE
• HC-SR04 ultrasonic sensor
• L298N motor driver
• 2× DC gear motors + wheels
• External battery pack
• Breadboard and jumper wires
• Chassis (or custom base)

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💻 Software

• STM32CubeIDE (HAL-based development)
• Embedded C
• Timer peripherals for PWM generation
• GPIO and timing logic for sensor interfacing

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📂 Repository Structure

pixel/

├── docs/ # system design and documentation

├── firmware/ # STM32 firmware (in progress)

├── hardware/ # wiring diagrams (in progress)

├── BOM.xlsx # bill of materials

└── README.md

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📚 Documentation

• System Design: docs/system_design.md
• BOM (Bill of Materials): BOM.xlsx

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🏁 Status

🟡 Planning & system design
⬜ Hardware assembly
⬜ Firmware implementation
⬜ Integration & testing

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🔧 Next Steps

• finalize hardware wiring and power setup
• implement PWM motor control
• implement ultrasonic distance measurement
• integrate real-time control loop

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🎯 Why this project matters

This project demonstrates:

• embedded systems development using STM32
• real-time control loop design
• sensor → decision → actuation pipelines
• hardware/software integration and debugging

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🧠 Future Improvements

• PID control for smoother navigation
• wheel encoders for closed-loop control
• Bluetooth or wireless control interface
• multi-sensor fusion

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👤 Author

Built by Mahi Joshi