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SplashPad

Published on: June 30, 2025

3 min read

SplashPad Banner
Hack Club Junior Year

SplashPad

A Tiny, Glowing, Feature-Packed Macropad for Maximum Efficiency™

(Or just a cool way to press “Play” on your music.)

Renders

Visuals because everyone loves eye candy.

BOM

All the bits and pieces needed can be found here.

What is this?

It’s a custom macropad built with the Seeed Studio XIAO RP2040, KMK firmware, and way too many LEDs. Whether you’re gaming, editing, coding, or just pressing random buttons for fun, this thing’s got you covered.

Features:

  • 3x3 Matrix – Nine glorious keys to map to whatever your heart desires.
  • Rotary Encoder – Twist for volume, scroll, or secret hacker functions.
  • Clickable Encoder Button – Because sometimes, twisting isn’t enough.
  • 14 SK6812 Mini LEDs – Way too many for a macropad this size. But hey, ✨blinkenlights✨.
  • Multiple LED Modes – Solid, Rainbow, Wave, and Grid Fade, for when you need that cyberpunk aesthetic.
  • KMK Firmware – Python-powered and open-source, because we like freedom.

How It Works:

This macropad runs either KMK or QMK, which means you get:

  • Custom Keymaps – Map macros, media keys, or even full-blown scripts.
  • Dynamic Layers – More functions per button? Yes, please.
  • LED Control – Pulsing blue? Rainbow waves? Subtle grid fade? Pick your poison.
  • Rotary Encoder Support – Spin for volume, brightness, scrolling, or whatever.

How to Use:

  1. Flash KMK onto your XIAO RP2040. (If you don’t know how, Google it.)
    or flash my QMK build from here.
  2. Drop kb.py and main.py onto your board.
    or use the QMK firmware provided in the link above.
  3. Plug it in. Watch the lights do their thing.
  4. Press buttons. Turn the knob. Make magic happen.

LED Modes:

Because a macropad without RGB is just a fancy calculator.

  • Solid Mode – A slow, pulsing blue (totally not just lazy coding).
  • Rainbow Mode – Taste the colors.
  • Wave Mode – Water flow effect because vibes.
  • Grid Fade Mode – Simulates sunlight through water. Or something poetic like that.

(Press the encoder button to switch between them.)

Why?

I built this macropad for Hackpad—an awesome Hack Club YSWS project run by Alex Ren. With a the funding provided by the project, I wanted to create something that’s as practical as it is playful. Whether you’re coding, gaming, or just jamming to your favorite tunes, this macropad is my way of saying:

why settle for ordinary when you can hack something extraordinary?

The Biggest Challenge:

I wanted to use nice thick wires for my PCB (0.6mm) and routing all of these took quite a bit of effort. I think the time spent was definitely worth it, as the routing looks awesome.

The Final Build:

After soldering everything together and putting it in the case, here’s how it looks:

(The super cool keycaps are from Undercity!)

Future Plans (Maybe):

  • OLED Screen? 🤔
  • Bluetooth support? (If I hate myself enough to deal with that.)
  • More layers? (How many is too many? Asking for a friend.)
  • MIDI support? (Why not turn this into a DJ controller?)

Disclaimer

This project is 100% free, open-source, and powered by vibes. If it breaks, explodes, or opens a black hole, that’s on you.

Propose a modification on GitHub