F24: Tilt Maze
Contents
Project Title
Tilt Maze
Abstract
Tilt Maze is a motion-controlled puzzle game that challenges players to navigate a luminous ball through procedurally generated mazes using device tilting mechanics. Players must reach the exit within time constraints while maneuvering around obstacles and collecting power-ups that provide temporary advantages. The game combines physical device control with strategic gameplay elements, offering high replayability through its randomized level design and emphasizing skills in balance, spatial reasoning, and quick decision-making.
Objectives & Introduction
The Tilt Maze Game combines hardware and software to create an interactive puzzle experience. It uses an ADXL345 accelerometer for tilt-based movement control, navigating a character through a maze displayed on a 64x64 LED matrix. FreeRTOS manages concurrent tasks like accelerometer input, display updates, and game logic, ensuring smooth and responsive gameplay. Game states, collision detection, and immersive audio feedback via an MP3 decoder enhance the experience. Semaphores and mutexes ensure thread-safe resource management, while debug outputs provide insights during development. This project demonstrates advanced integration of peripherals and real-time systems in a cohesive gaming application.
Team Members & Responsibilities
- Shreya Belide
- Jyoshna Mallineni
- Pavan Charith
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BILL OF MATERIALS
| Part | # | Cost | Source |
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| SJ2 Board | 1 | $50.00 | Preet |
| Sparkfun RGB (64x64) LED Matrix Display | 1 | $65.72 | Amazon |
| Accelerometer | 1 | $10.99 | JLC PCB |
| 12v DC Power Jack Adapter Connector | 1 | $8.90 | Amazon |
| MP3 Decoder | 1 | 6.90 | Amazon |
| Packaging | 1 | $12 | Target |
| Jumper Wires | 1 | $6.99 | Amazon |
| Total Cost | $173.20 |
Design & Implementation
The design section can go over your hardware and software design. Organize this section using sub-sections that go over your design and implementation.
Hardware Design
Discuss your hardware design here. Show detailed schematics, and the interface here.
Hardware Interface
In this section, you can describe how your hardware communicates, such as which BUSes used. You can discuss your driver implementation here, such that the Software Design section is isolated to talk about high level workings rather than inner working of your project.
Software Design
Show your software design. For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level. Do not show the details of the code. For example, do not show exact code, but you may show psuedocode and fragments of code. Keep in mind that you are showing DESIGN of your software, not the inner workings of it.
Implementation
- **LED Matrix Driver Functions**:
- 1. `matrix_init`: Initializes GPIO pins for the RGB LED matrix and sets up the synchronization mutex:contentReference[oaicite:0]{index=0}.
- 2. `display_update`: Refreshes the LED matrix display to reflect any changes:contentReference[oaicite:1]{index=1}.
- 3. `display_clear`: Clears all active pixels on the matrix by setting them to zero:contentReference[oaicite:2]{index=2}.
- 4. `overwrite_pattern_to_screen`: Overwrites a specific pattern onto the LED matrix:contentReference[oaicite:3]{index=3}.8
- 5. `append_pattern_to_screen`: Adds a pattern to the existing screen matrix without overwriting:contentReference[oaicite:4]{index=4}.
- **Accelerometer Driver**:
- 1. `accelerometer_init`: Configures the ADXL345 accelerometer with ±2g sensitivity and sets up I2C communication with semaphores for thread safety:contentReference[oaicite:5]{index=5}.
- 2. `accelerometer_task`: Periodically reads acceleration data, applies smoothing, and updates player position based on tilt movements:contentReference[oaicite:6]{index=6}.
- Maze Logic:
- 1. `get_maze_layout`: Retrieves the maze pattern for the current level:contentReference[oaicite:7]{index=7}.
- 2. `is_wall_at`: Checks if a specific position in the maze contains a wall, used to constrain player movement:contentReference[oaicite:8]{index=8}.
- 3. `is_goal_at`: Determines if the player has reached the maze's goal position to proceed to the next level:contentReference[oaicite:9]{index=9}.
- **Game Logic**:
- 1. `set_player_to_start`: Resets the player position to the starting point of the current level:contentReference[oaicite:10]{index=10}.
- 2. `handle_collisions`: Detects collisions with walls, traps, and goals, triggering state changes like `GAME_STATE_GAME_OVER` or `GAME_STATE_LEVEL_UP`:contentReference[oaicite:11]{index=11}.
- 3. `change_game_state`: Manages game states such as `GAME_STATE_TITLE`, `GAME_STATE_PLAYING`, and `GAME_STATE_WIN`, and handles music transitions:contentReference[oaicite:12]{index=12}.
- **MP3 Decoder**:
- 1. `mp3_decoder__init`: Initializes the MP3 decoder, sets the default volume, and selects the storage device:contentReference[oaicite:13]{index=13}.
- 2. `mp3_decoder__play_song_at_index`: Plays a specific song based on its index in single-cycle mode:contentReference[oaicite:14]{index=14}.
- 3. `mp3_decoder__play_song_with_mode`: Allows playback in loop or single-cycle mode, depending on the game state:contentReference[oaicite:15]{index=15}.
- 4. `mp3_decoder__stop_playback`: Stops any active song playback:contentReference[oaicite:16]{index=16}.
- 5. `mp3_decoder__volume_set_level`: Adjusts the volume level of the MP3 decoder:contentReference[oaicite:17]{index=17}.
Testing & Technical Challenges
The most challenging part of the Tilt Maze game was the integration and calibration of the accelerometer. Reading accurate tilt data and translating it into smooth, responsive movements for the game character required careful implementation. Additionally, ensuring the player's movement was constrained within the maze boundaries while avoiding unintended behavior added complexity.
Bug/Issue Name
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Conclusion
Building the Tilt Maze game on a microcontroller proved to be a rewarding and challenging experience. Developing custom drivers for the accelerometer, LED matrix, and MP3 decoder required a deep understanding of embedded systems. Implementing FreeRTOS tasks to handle concurrent updates for accelerometer input, game logic, and display rendering added complexity but ensured smooth and responsive gameplay. One of the most challenging aspects was achieving accurate and stable accelerometer readings for tilt detection, which required calibration, noise filtering, and careful logic for player movement.
Throughout the project, we encountered various issues, including synchronization conflicts, noisy sensor data, and priority balancing in FreeRTOS. These challenges taught us the importance of debugging, modular design, and leveraging RTOS APIs effectively. As embedded engineers, we learned that creating a system from scratch involves meticulous attention to both hardware and software integration.
In the end, we successfully implemented a fun and interactive game that showcases the power of embedded systems. Future improvements could include adding a scoring system, dynamic maze generation, and more refined accelerometer controls to further enhance gameplay.
Project Video
[Watch the Tilt Maze game demo](https://youtu.be/QRE9pQ7dBBg)
Project Source Code
References
Acknowledgement
Special thanks to Mr. Preet Kang for his lessons and detailed-documentation website on microcontrollers.
References Used
- 1. Mp3 user manual: https://usermanual.wiki/Pdf/Serial20MP320Player20v10120Manual.2117229468/view
- 2. LPC40xx_FreeRtos Github: https://gitlab.com/sjtwo-c-dev/sjtwo-c
Appendix
- 1. LPC40xx_FreeRtos Github: https://gitlab.com/sjtwo-c-dev/sjtwo-c
- 2. FreeRTOS: https://www.freertos.org/a00116.html
