4 layers117.3 × 78.7 mm
OSMC Receiver
Koalaven/Open-Source-Modular-Controller
A modular controller that can be configure to how you want to use it
91 parts
4 layers34 × 41 mm
OSMC Module Buttons
Koalaven/Open-Source-Modular-ControllerA modular controller that can be configure to how you want to use it
- Size
- 34 × 41 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 11
- Nets
- 22
- Pads
- 77
- Tracks, vias
- 124, 28
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 1 Sep 2025
- Updated
- 23 Apr 2026
Overview
OSMC Module Buttons is an open-source printed circuit board by Koalaven, from the Koalaven/Open-Source-Modular-Controller repository on GitHub. It is a 4-layer board of 34 × 41 mm with 11 parts on 22 nets, routed with 124 tracks and 28 vias.
It is built around the PCF8574DWR and 24LC02BT-I/OT. Its parts include 4 connectors, 4 switches and 3 ICs.
Main components
2
PCF8574DWR
SOIC-16-300mil-40℃~+85℃ 100kHz 10uA 2.5V~6V 25mA 30uA 8 I2C Interrupt Output Push-Pull Reset function、Cascading and address extension、Built-in LED driver SOIC-16-300mil I/O Expanders ROHSTexas InstrumentsI/O Expanders
24LC02BT-I/OT
SOT-23-5-40℃~+85℃ 1,000,000 cycles 2.5V~5.5V 200 Years 2Kbit 400kHz 5ms Hardware write protection function、Noise suppression function I2C SOT-23-5 EEPROM ROHSMicrochip TechnologyEEPROM
README
README.mdOpen Source Modular Controller
Using a modular, reconfigurable hardware architecture to create a customizable USB HID game controller.
Project Details
The Open Source Modular Controller project is a fully modular and customizable gaming input system. Users can freely rearrange joysticks, buttons, and future input modules on a set of interchangeable receiver boards to build a layout that fits their gameplay style, ergonomic needs, or accessibility requirements.
The controller connects over USB and is recognized as a standard Human Interface Device (HID) with no additional drivers required.
Current State
The current prototype includes:
- A functional ESP32‑S3‑based main controller
- Hot-swappable joystick and button modules
- Receiver boards that can be placed anywhere in the 3D‑printed shell
- USB HID communication via TinyUSB
The system operates as a recognized USB gamepad on Windows. Some hardware issues were identified and corrected in updated revisions.
Project Structure
The repository is organized as follows:
- Firmware – ESP32‑S3 code handling HID communication and module input processing.
Link: Firmware - Software – PC‑side utilities or test scripts (coming soon).
- Hardware – KiCad project files, schematics, PCBs, and 3D‑printed shell models.
Link: Hardware - Documentation – Assembly instructions, diagrams, semester report, and testing notes.
Link: Documentation
Features
- Modular input modules (buttons, joystick, future sensors)
- Repositionable input layout using multiple receiver boards
- ESP32‑S3 native USB HID support
- Open‑source hardware and firmware
- 3D‑printable ergonomic controller shell
System Architecture
Core system components include:
- Receiver boards distributing power, signals, and micro-controller
- Module boards for inputs (joystick/button)
- 3D‑printed enclosure with heat‑set inserts for secure mounting
USB HID enumeration and report handling are implemented using TinyUSB. Modules communicate through standardized connectors to the controller board.
Bill of Materials
A full BOM including the ESP32‑S3 boards, connector sets, resistors, capacitors, PCBs, wire, and 3D‑printed components is provided in the documentation.
BOM
Tools Used
Software
- Arduino IDE
- KiCad
- OnShape (frame design)
- GitHub Desktop
- Cura slicer
Hardware
- 3D printer
- Soldering iron
- Hot air station
- Multimeter
- Tweezers
Assembly Overview
- Gather materials (refer to BOM).
- Order PCBs (Gerber files included).
- 3D print shell and module housings.
- Clean and prepare boards.
- Solder components (headers, ESP32 module, connectors, buttons/joysticks).
- Upload firmware via Arduino IDE.
- Install modules into the shell.
- Test controller.
What the Project Could Use Next
- On‑board processing for more advanced input mapping
- PCB adjustment and testing
- Wireless mode using Bluetooth HID
- Additional module types (battery, gyroscope, sliders, touchpads)
Semester End Report
For the Enterprise Program at Michigan Tech there is a end of semester and project report for the project to summarize the progress of the project. Link
Acknowledgements
This project is supported by the Open Source Hardware Enterprise at Michigan Technological University.
Helpful Links
References
Parts
11| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | SW_Push | footprints:SW_Push_1P1T_XKB_TS-1187A | SW1, SW2, SW3, SW4 |
| 3 | SolderJumper_2_Bridged | Jumper:SolderJumper-2_P1.3mm_Bridged2Bar_Pad1.0x1.5mm | J1, J2, J3 |
| 1 | 24LC02BT-I/OT | Library:SOT-23-5_MC_MCH | U2 |
| 1 | Conn_01x08_Socket | Library:OSMC_Button_Membrane | J1 |
| 1 | OSMC Module Board w/pins | Library:Module standard pin large | U1 |
| 1 | PCF8574DWR | Library:DW16 | U3 |
Questions
How big is the OSMC Module Buttons PCB?
It measures 34 × 41 mm and has 4 copper layers, 1.6 mm thick.
What parts does the OSMC Module Buttons use?
11 parts, built around the PCF8574DWR and 24LC02BT-I/OT. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the OSMC Module Buttons KiCad files?
From the Koalaven/Open-Source-Modular-Controller repository on GitHub, at the commit this page was made from: the board is Hardware/PCBs/module/OSMC_Module_Buttons/OSMC_Module_Buttons.kicad_pcb and its schematic Hardware/PCBs/OSMC_Receiver/Modules.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the OSMC Module Buttons design in my own project?
Its repository states no licence, so its author keeps all rights: ask Koalaven before reusing the design.
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