Project/vlad mihnea.ene

website/versioned_docs/version-acs_cc/project/2026/vlad_mihnea.ene/index.md

@@ -4,53 +4,55 @@ A wireless arcade game controller built with Rust and Embassy on STM32 Nucleo-U5
 :::info
 
 **Author:** Ene Vlad-Mihnea
-**GitHub Project Link:** [link_to_github](https://github.com/UPB-PMRust-Students/acs-project-2026-enevlad)
+**GitHub Project Link:** [RustPad](https://github.com/UPB-PMRust-Students/acs-project-2026-enevlad)
 
 :::
 
 ## Description
 
-THe project is a wireless game controller based on the STM32 Nucleo-U545RE-Q microcontroller,
+RustPad is a wireless game controller based on the STM32 Nucleo-U545RE-Q microcontroller,
 programmed in Rust using the Embassy async framework. It features an analog joystick, four
-digital action buttons, an SSD1306 OLED display showing battery level and Bluetooth status,
-rumble feedback via a vibration motor, and wireless communication over Bluetooth (HC-05).
-Power is provided by a LiPo battery with a TP4056 charging module. All components are mounted
-on an open acrylic frame, making the hardware fully visible and accessible.
+digital action buttons, an SSD1306 OLED display showing Bluetooth connection status,
+rumble feedback via a PWM vibration motor module, and wireless communication over Bluetooth
+(HC-05). The controller is recognised by any game on Linux through a virtual gamepad created
+with uinput, bridged by a companion Rust application running on the host PC.
 
 ## Motivation
 
-My motivation for this project stems directly from my passion/hobby for gaming. Building one from scratch in Rust
-provides hands-on experience with ADC sampling, GPIO interrupts, UART-based wireless protocols,
-and async embedded programming — all within a single cohesive project. Rust's ownership model
-makes it especially suitable for embedded development: memory safety without a runtime and
-strong type guarantees that catch peripheral misconfigurations at compile time.
+My motivation for this project stems directly from my passion for gaming. Building a controller
+from scratch in Rust provides hands-on experience with ADC sampling, GPIO interrupts,
+UART-based wireless protocols, and async embedded programming — all within a single cohesive
+project. Rust's ownership model makes it especially suitable for embedded development: memory
+safety without a runtime and strong type guarantees that catch peripheral misconfigurations at
+compile time.
 
 ## Architecture
 
-The system is split into four main components:
+The system is split into two main parts: **firmware** running on the Nucleo and a **bridge
+application** running on the host PC.
 
-**Input Layer** — The KY-023 analog joystick sampled via ADC and four tactile buttons read via
-GPIO interrupts. All input state is collected into a shared data structure protected by an
-Embassy Mutex.
+**Input Layer** — The KY-023 analog joystick is sampled via ADC on PA0 and PA1. Four tactile
+buttons are read via GPIO with internal pull-ups on PB0–PB3. Input state is collected every
+20 ms in the main Embassy loop.
 
-**Processing Layer** — The STM32 Nucleo-U545RE-Q runs an Embassy async executor with separate
-tasks for ADC sampling, button handling, display updates, battery monitoring, and Bluetooth
-transmission.
+**Communication Layer** — The HC-05 Bluetooth module communicates with the MCU over USART1 at
+115200 baud. Controller frames (`X:50 Y:-30 BTN:0101`) are sent to the host PC every 20 ms.
+The HC-05 STATE pin on PC0 is used to detect Bluetooth connection status.
 
-**Communication Layer** — An HC-05 Bluetooth module receives serialised controller frames over
-USART every 10 ms and forwards them to the host PC wirelessly. On the PC side, a Python script
-reads the frames from the Bluetooth COM port and forwards them to a vJoy virtual gamepad,
-making the controller recognised by any game with gamepad support.
+**Output Layer** — An SSD1306 OLED display shows connection status over I²C (updated only on
+BT status change). A PWM vibration motor module on PA8 provides haptic feedback, triggered
+either by button press or by a rumble command (`V`) received from the host.
 
-**Output Layer** — An SSD1306 OLED display shows Bluetooth connection status and battery level
-over I²C. A coin vibration motor driven via PWM through an N-MOSFET provides haptic feedback.
+**Host Bridge** — A Rust application on the PC connects to the HC-05 via Bluetooth RFCOMM,
+parses controller frames and forwards them to a uinput virtual gamepad, making the controller
+recognised by any Linux game.
 
 ## Log
 
 ### Week 5 - 11 May
 
-Selected project components and ordered hardware. Set up the Rust/Embassy development 
-environment with the correct toolchain (1.90) and probe-rs for flashing. Tested basic 
+Selected project components and ordered hardware. Set up the Rust/Embassy development
+environment with the correct toolchain (1.90) and probe-rs for flashing. Tested basic
 project compilation for the STM32 Nucleo-U545RE-Q target.
 
 ### Week 12 - 18 May
@@ -61,14 +63,20 @@ All components confirmed working. Created EasyEDA schematic with all connections
 
 ### Week 19 - 25 May
 
+Integrated all components into the main controller firmware. Implemented Bluetooth communication
+at 115200 baud (after AT command reconfiguration of HC-05). Developed the host bridge
+application in Rust using bluer and evdev. Tested full controller functionality in SuperTuxKart
+on Linux. Implemented haptic feedback via vibration motor triggered by button press.
+
 ## Hardware
 
 The controller is built around the **STM32 Nucleo-U545RE-Q** (ARM Cortex-M33, 160 MHz). Input
-comes from a **KY-023 analog joystick module** connected to two ADC channels and four
-**tactile push buttons** on GPIO pins with internal pull-ups. Wireless communication is handled
-by an **HC-05 Bluetooth module** over USART. An **SSD1306 OLED 128×64** display is connected
-via I²C and shows battery level and connection status. A **PWM vibration motor module**
-(3–5V, with integrated driver) provides rumble feedback.
+comes from a **KY-023 analog joystick module** connected to two ADC channels (PA0, PA1) and
+four **tactile push buttons** on GPIO pins PB0–PB3 with internal pull-ups. Wireless
+communication is handled by an **HC-05 Bluetooth module** over USART1 (PA9/PA10) at 115200
+baud. An **SSD1306 OLED 128×64** display is connected via I²C (PB6/PB7) and shows Bluetooth
+connection status. A **PWM vibration motor module** (3–5V, integrated driver) on PA8 provides
+haptic feedback.
 
 ## Schematics
 
@@ -79,32 +87,39 @@ via I²C and shows battery level and connection status. A **PWM vibration motor
 | Device | Usage | Price |
 |--------|-------|-------|
 | [STM32 Nucleo-U545RE-Q](https://www.st.com/en/evaluation-tools/nucleo-u545re-q.html) | Main microcontroller | ~60 RON |
-| [KY-023 Analog Joystick](https://www.optimusdigital.ro) × 2 | Analog axis input | ~10 RON |
+| [KY-023 Analog Joystick](https://www.optimusdigital.ro) | Analog axis input (X/Y) | ~5 RON |
 | [HC-05 Bluetooth Module](https://www.optimusdigital.ro) | Wireless UART communication | ~18 RON |
-| [SSD1306 OLED 128×64 I²C](https://www.optimusdigital.ro) | Battery + BT status display | ~15 RON |
-| [Tactile push buttons](https://www.optimusdigital.ro) × 6 | Action buttons | ~3 RON |
-| [Modul motor vibratii PWM 3-5V](https://sigmanortec.ro/modul-motor-vibratii-dc-control-pwm-3-5v) | Rumble / haptic feedback | ~5 RON | 
-| [TP4056 Charger Module](https://www.optimusdigital.ro) | LiPo USB charging + protection | ~6 RON |
-| LiPo Battery 3.7V 1000mAh | Power source | ~20 RON |
-| AMS1117-3.3 LDO Regulator | 3.3V power supply | ~2 RON |
-| Perfboard + wires + resistors | Wiring and assembly | ~10 RON |
+| [SSD1306 OLED 128×64 I²C](https://www.optimusdigital.ro) | BT status display | ~15 RON |
+| [Tactile push buttons](https://www.optimusdigital.ro) × 4 | Action buttons | ~2 RON |
+| [Modul motor vibratii PWM 3-5V](https://sigmanortec.ro/modul-motor-vibratii-dc-control-pwm-3-5v) | Rumble / haptic feedback | ~10 RON |
+| Breadboard + wires | Wiring and assembly | ~10 RON |
 
 ## Software
 
+### Firmware (STM32 Nucleo)
+
 | Library | Description | Usage |
 |---------|-------------|-------|
 | [embassy-stm32](https://github.com/embassy-rs/embassy) | Async HAL for STM32 | ADC, GPIO, USART, I²C, PWM peripherals |
-| [embassy-executor](https://github.com/embassy-rs/embassy) | Async task executor for embedded | Running concurrent tasks on the MCU |
-| [ssd1306](https://github.com/jamwaffles/ssd1306) | Display driver for SSD1306 OLED | Rendering battery level and BT status |
-| [embedded-graphics](https://github.com/embedded-graphics/embedded-graphics) | 2D graphics library | Drawing text and shapes to the OLED |
+| [embassy-executor](https://github.com/embassy-rs/embassy) | Async task executor for embedded | Main async loop on the MCU |
+| [embassy-time](https://github.com/embassy-rs/embassy) | Time abstractions for embedded | Timers and delays |
+| [ssd1306](https://github.com/jamwaffles/ssd1306) | Display driver for SSD1306 OLED | Rendering BT status on the display |
+| [embedded-graphics](https://github.com/embedded-graphics/embedded-graphics) | 2D graphics library | Drawing text to the OLED |
+| [embedded-hal](https://github.com/rust-embedded/embedded-hal) | Hardware abstraction traits | PWM control for vibration motor |
 | [defmt](https://github.com/knurling-rs/defmt) | Logging framework for embedded Rust | Debug output via probe-rs |
-| [pyserial](https://pypi.org/project/pyserial/) (PC) | Serial communication in Python | Reading Bluetooth frames on the host PC |
-| [vJoy](https://github.com/njz3/vJoy/) (PC) | Virtual gamepad driver | Exposing controller as HID gamepad to games |
+| [heapless](https://github.com/rust-embedded/heapless) | Static data structures | String formatting without heap |
 
-## Links
+### Host Bridge (Linux PC)
 
-<!-- Add a few links that inspired you and that you think you will use for your project -->
+| Library | Description | Usage |
+|---------|-------------|-------|
+| [bluer](https://github.com/bluez/bluer) | Bluetooth library for Rust | RFCOMM connection to HC-05 |
+| [evdev](https://github.com/emberian/evdev) | Linux input device library | Creating virtual gamepad via uinput |
+| [tokio](https://tokio.rs) | Async runtime for Rust | Async Bluetooth I/O on the host |
+
+## Links
 
-1. [link](https://example.com)
-2. [link](https://example3.com)
-...
+1. [Embassy Framework](https://embassy.dev)
+2. [STM32 Nucleo-U545RE-Q User Manual](https://www.st.com/resource/en/user_manual/um3062-stm32u3u5-nucleo64-boards-mb1841-stmicroelectronics.pdf)
+3. [SSD1306 Datasheet](https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf)
+4. [HC-05 AT Commands Reference](https://www.instructables.com/AT-command-mode-of-HC-05-Bluetooth-module/)