2 layers19 × 76 mm
Sub
google/mozc-devices
Circuit diagrams and firmware source code for Gboard DIY keyboards
15 parts3kApache-2.0
2 layers50.8 × 50.8 mm
Mobilemashbuddy
gregsimon/mobilemashbuddyMobileMash Buddy is a custom companion PCB designed for the MobileMash physical button-mashing harness. It provides a compact, dedicated controller platform based on the Seeed Studio XIAO ESP32-S3 microcontroller.
- Size
- 50.8 × 50.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 15
- Nets
- 16
- Pads
- 59
- Tracks, vias
- 125, 3
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 9 Jul 2026
- Updated
- 18 Jul 2026
Overview
Mobilemashbuddy is an open-source printed circuit board by gregsimon, from the gregsimon/mobilemashbuddy repository on GitHub, published under the Apache-2.0 licence. It is a 2-layer board of 50.8 × 50.8 mm with 15 parts on 16 nets, routed with 125 tracks and 3 vias.
Its parts include 4 connectors, 3 capacitors, 2 ICs and 2 switches. It belongs with the ESP32 and RISC-V boards of this library.
README
README.mdMobileMash Buddy
MobileMash Buddy is a custom companion PCB designed for the MobileMash physical button-mashing harness. It provides a compact, dedicated controller platform based on the Seeed Studio XIAO ESP32-S3 microcontroller.
The board interfaces directly with the servo motors of the MobileMash harness while adding local physical control inputs for activation of functions and tuning without an attached computer (rotary encoder and push buttons).
Features
- Microcontroller: Support for the ultra-compact Seeed Studio XIAO ESP32-S3.
- Servo Control: 3x servo PWM channels (compatible with SG90 micro servos):
- PWR (Power button servo)
- VOL+ (Volume-up button servo)
- VOL- (Volume-down button servo)
- Interactive Controls:
- 1x Rotary Encoder (with integrated click switch) for menu navigation.
- 1x General-purpose tactile push button (BTN1) for triggers / actions.
- Display Support: Header for a standard 4-pin I2C OLED display (SSD1306 128x64 or 128x32).
- Power System: Power via USB-C (for the XIAO and display) and external center-positive DC jack to supply dedicated power to the servo channels.
Hardware Reference & Pinout
Below is the actual pin assignment table for the Seeed Studio XIAO ESP32-S3 as routed in the KiCad schematic:
| XIAO Pin Label | ESP32-S3 GPIO | Component / Label | Function / Role |
|---|---|---|---|
| D0 | GPIO 1 | — | Unused / No Connect (NC) |
| D1 | GPIO 2 | — | Unused / No Connect (NC) |
| D2 | GPIO 3 | OLED Display - SDA | I2C Data |
| D3 | GPIO 4 | OLED Display - SCL | I2C Clock |
| D4 | GPIO 5 | Rotary Encoder - DT (B) | Input (ENC_B) |
| D5 | GPIO 6 | Rotary Encoder - SW (Click) | Digital Input (ENC_SW) |
| D6 | GPIO 43 | Push Button 1 | Digital Input (BTN1) |
| D7 | GPIO 44 | Rotary Encoder - CLK (A) | Input (ENC_A) |
| D8 | GPIO 21 | Servo 3 (VOL-) | PWM Control Signal (SERVO3) |
| D9 | GPIO 7 | Servo 2 (VOL+) | PWM Control Signal (SERVO2) |
| D10 | GPIO 8 | Servo 1 (PWR) | PWM Control Signal (SERVO1) |
| 3V3 | — | OLED Display - VCC | 3.3V Power Output for the Display |
| GND | — | Common Ground | Connected to OLED GND, button, encoder, and servo power GND |
Repository Structure
mobilemashbuddy.kicad_pro/mobilemashbuddy.kicad_sch/mobilemashbuddy.kicad_pcb: The core KiCad project, schematic, and board layout files.lib/: KiCad footprint and symbol libraries, including:- Custom symbols/footprints for the Seeed Studio XIAO ESP32-S3.
- Footprints for the SSD1306 OLED module and vertical Alps EC11E rotary encoder.
Polarity_marking_center_positive.svg: Graphic file for the power jack polarity indicator.
Getting Started
- Open in KiCad:
Open the
mobilemashbuddy.kicad_proproject using KiCad (compatible with KiCad 8.0 / 9.0). - Manufacture the Board: Export the Gerber and drill files from KiCad to manufacture the PCB at any standard fabrication house.
- Assemble: Solder the components using the schematic reference. Be sure to check polarities on the power input connector and capacitors.
- Firmware: Upload appropriate control firmware to the Seeed Studio XIAO ESP32-S3 to control the servos and interface with the MobileMash system.
License
This project is licensed under the Apache License 2.0. See the LICENSE file for details.
Parts
15| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | MountingHole_Pad | MountingHole:MountingHole_2.5mm_Pad_TopBottom | H5, H6, H7, H8 |
| 2 | 100nF | Capacitor_SMD:C_1206_3216Metric | C2, C3 |
| 1 | 470uF | Capacitor_SMD:CP_Elec_8x10.5 | C1 |
| 1 | Barrel_Jack_Switch | Connector_BarrelJack:BarrelJack_Horizontal | J1 |
| 1 | EC11 | Rotary_Encoder:RotaryEncoder_Alps_EC11E-Switch_Vertical_H20mm | SW3 |
| 1 | KEY1 | Button_Switch_THT:SW_PUSH_6mm_H5mm | SW1 |
| 1 | PWR | Connector_PinSocket_2.54mm:PinSocket_1x03_P2.54mm_Vertical | J2 |
| 1 | SSD1306 OLED | SSD1306:128x64OLED | U2 |
| 1 | VOL+ | Connector_PinSocket_2.54mm:PinSocket_1x03_P2.54mm_Vertical | J3 |
| 1 | VOL- | Connector_PinSocket_2.54mm:PinSocket_1x03_P2.54mm_Vertical | J5 |
| 1 | XIAO ESP32-C6 | XIAO_ESP32S3:XIAO_ESP32S3 | U1 |
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Questions
How big is the Mobilemashbuddy PCB?
It measures 50.8 × 50.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Mobilemashbuddy use?
15 parts. 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 Mobilemashbuddy KiCad files?
From the gregsimon/mobilemashbuddy repository on GitHub, at the commit this page was made from: the board is mobilemashbuddy.kicad_pcb and its schematic mobilemashbuddy.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Mobilemashbuddy design in my own project?
Its repository publishes it under the Apache-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).