WALL-E (Self Balancing Robot)

Contents

• Overview
  • Features
  • Components
• System Design
  • Functional Diagram
  • Architecture Diagram
• Robot Firmware
  • Arduino
  • STM32
• User Software
  • Driver App
  • Dashboard App
• Demonstration
• Credit

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Overview

We designed WALL-E, an autonomously balancing two-wheel robot driven wirelessly via Bluetooth.

Features

WALL-E prioritizes safe navigation and secure access.

• Detects the nearby environment (i.e. obstacles, color recognition)
• Prevents unauthorized control with RFID authentication and BLE pairing code.
• Generates live camera feed and uploads to AWS S3 cloud storage.

Components

• Microcontrollers:

  • Arduino Nano 33 BLE Sense Rev2 (Balancing & BLE)
  • STM32L051K8T6 (Environmental Sensors, Auth)
  • Raspberry Pi Zero 2 W (Camera Feed)

• Sensors and Modules:

  • BMM150 IMU
  • HC-SR04 Ultrasonic Distance Sensor
  • TCS34725 Color Sensor
  • RC522 RFID Module
  • CEM-1302 Buzzer
  • Freenove 5MP Camera

• Actuation:

  • DRV8833 Motor Drivers
  • Pololu 37D DC Motors

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System Design

Functional Diagram

Architecture Diagram

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Robot Firmware

Arduino

• Autonomously balances robot with closed-loop control system (i.e. PID controller).
• Uses complementary filter to measure angular input from accelerometer and gyroscope sensors.
• Drives motors by generating PWM (slow decay) output to DRV8833 chip.
• Uses statemachine to prioritize balancing / movement functionality.
  • Injects noise (i.e. angular offset, PWM signals) to induce movement along axis / turning.

Source Code in Arduino_Firmware directory.

STM32

• Handles auxiliary features to reduce computational load on Arduino.
  • Distance Sensing: Toggles GPIO signal-low when object detected within 30cm.
  • Color Detection: Toggles GPIO signal-low when red is detected. WALL-E avoids red-lights at all costs.
  • RFID Authentication: Verifies UID and signals Arduino on success.
  • Buzzer: Alerts user on successful auth, errors, or warnings via PWM tone generation.

Source Code in STM32_Firmware directory.

User Software

Robot Driver App

• Flask web application hosted via ngrok for mobile access
• Uses GET/POST requests to update server with UI updates and perform Bluetooth operations.
• Handles BLE pairing authentication in backend (i.e. without affecting user experience).

Source Code in Driver_App directory.

Dashboard App

• Python application with live camera stream on Tkinter GUI.
  • Camera runs at ~20 FPS with reduced resolution for performance on Pi Zero 2 W.
• Snapshot and recording functionality with automatic upload to AWS S3 bucket.

Source Code in Dashboard_App directory.

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Demonstration

Watch our final robot demonstration here: 📽️ YouTube Demo

Report

Read our final project report here: 📝 Project Report

Credit

This was completed as part of the ELEC 391 - Design Studio project course in The University of British Columbia Electrical and Computer Engineering undergraduate program.

Team B-17

• Muntakim Rahman
• Tomaz Zlindra
• Xianyao Li

Special thanks to Dr. Joseph Yan for tremendous support and guidance.