2 layers50 × 35 mm
2 layers44.8 × 73.8 mm
Pathfinder
Rainier-PS/GridCoreGridCore is a modular 2×2 LED grid game and tool platform built for the Xiao RP2040.
- Size
- 44.8 × 73.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 17
- Nets
- 18
- Pads
- 80
- Tracks, vias
- 91, 0
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 25 Jul 2025
- Updated
- 30 Dec 2025
Overview
Pathfinder is an open-source printed circuit board by Rainier-PS, from the Rainier-PS/GridCore repository on GitHub. It is a 2-layer board of 44.8 × 73.8 mm with 17 parts on 18 nets, routed with 91 tracks and 0 vias.
Its parts include 4 resistors, 4 diodes, 4 switches and 3 connectors. It belongs with the RP2040 boards of this library.
README
README.mdGridCore
GridCore is a minimalist reaction-based game system built on a 2×2 LED grid with 4 buttons. Modular. Expandable. Fun.
What is GridCore?
GridCore is a lightweight, open-source mini game console using only 4 buttons and a 2×2 LED grid. GridCore is designed to be fun, hackable, and extendable. It runs simple games like reaction challenges with plans for more in future updates. (more games)
Images
Schematic
PCB Layout
PCB Front (Render)
PCB Back (Render)
GridCore Board - Front
GridCore Board - Back
Features
- Reaction-based game logic that gets harder with each level
- Built-in splash screen animation
- MX keys 4-button control
- Organized, human-readable code
- Easily expandable architecture for additional games/tools
How to Play
- Watch for a random LED to light up.
- Press the corresponding button as fast as possible.
- Get it right? You level up and it gets faster.
- Miss or timeout? The game restarts.
Button–LED Layout
(Button position ≠ LED index)
| Button No. | Position | LED No. | LED Position |
|---|---|---|---|
| Button 1 | Top Left | LED 3 | Upper Right |
| Button 2 | Top Right | LED 2 | Upper Left |
| Button 3 | Bottom Left | LED 1 | Lower Left |
| Button 4 | Bottom Right | LED 4 | Lower Right |
Future Plans
- Add multiple minigames (reaction, memory, binary input)
- Tool modes (timer, counter, morse trainer, etc)
Getting Started
1. Flash the Code
Upload the GridCore.ino sketch to your board using Arduino IDE or PlatformIO.
2. Wiring
| Function | GPIO Pin | Notes |
|---|---|---|
| Button 1 | GPIO26 | Pull-down |
| Button 2 | GPIO27 | Pull-down |
| Button 3 | GPIO28 | Pull-down |
| Button 4 | GPIO29 | Pull-down |
| LED 1 | GPIO0 | Lower Left |
| LED 2 | GPIO7 | Upper Left |
| LED 3 | GPIO6 | Upper Right |
| LED 4 | GPIO1 | Lower Right |
Advanced Notes
-
GND Test Pad
A dedicated exposed GND pad is included on the PCB for easy multimeter probing and diagnostics. Useful during debugging or for adding temporary modules or sensors. -
Dual Pin Headers for Xiao
The Xiao RP2040 footprint includes double/duplicate pin holes, one for standard mounting, and another inline set for breakout or jumper wiring. This allows GridCore to be used not only as a game system, but also as a hackable Xiao devboard for rapid prototyping.
Note
This project has passed both ERC (Electrical Rule Check) and DRC (Design Rule Check) with no errors. All submission requirements for Pathfinder have been completed.
Parts
17| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | L08R5000Q1 | Footprints:LEDRD254W57D500H1070 | D1, D2, D3, D4 |
| 4 | R | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R1, R2, R3, R4 |
| 4 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_PCB | SW1, SW2, SW3, SW4 |
| 2 | Conn_01x07 | Footprints:PinHeader_1x07_P2.54mm_Vertical | J1, J2 |
| 1 | Conn_01x01 | TestPoint:TestPoint_THTPad_D1.5mm_Drill0.7mm | J3 |
| 1 | XIAO-RP2040-DIP | Footprints:XIAO-RP2040-DIP | XIAO-RP2040 |
The 16 most common of 17 parts.
Questions
How big is the Pathfinder PCB?
It measures 44.8 × 73.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Pathfinder use?
17 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 Pathfinder KiCad files?
From the Rainier-PS/GridCore repository on GitHub, at the commit this page was made from: the board is PCB/Pathfinder.kicad_pcb and its schematic PCB/Pathfinder.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Pathfinder design in my own project?
Its repository states no licence, so its author keeps all rights: ask Rainier-PS before reusing the design.
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