Controller

Controller!

This is my first custom hardware module for the hackxpansion console. It combines a physical rotary encoder knob with two extra push buttons so you can scroll through menus, tweak settings, and play games with tactile controls.

Design

I wanted to build something practical for menu navigation without taking up too much space.

I combined a standard EC11 rotary encoder (with its built-in push switch) alongside two standalone push buttons. The encoder handles spinning controls for scrolling lists or adjusting levels, while the buttons give you quick action controls for selecting items or going back.

Schematic

I made this schematic in KiCad by routing the encoder pins (GPIO0 & GPIO1), the two external buttons (GPIO2 & GPIO3), and the encoder shaft button (GPIO4) directly to the hackxpansion pin headers.

Layout

The board layout fits a single hackxpansion module slot. It uses a standard 2-layer PCB with ground planes on both top and bottom layers.

You can inspect the design in your browser using the Live Interactive PCB Layout (KiCanvas).

Case & 3D Model

I modeled the enclosure in Fusion 360 using the hackxpansion base template. The shell holds the PCB using two M2 screws from the back so the knob and buttons stay solid when pressed.

Check out the interactive 3D model via the Fusion 360 Live Web Link.

Software & Hardware Config

The driver for this module was built in Rust using xpanse-api.

• Public Project Page: https://hackxpansion.hackclub.com/explore/1k:36k
• MD0 Resistor: 1kΩ (R1K)
• MD1 Resistor: 36kΩ (R36K)

Pin mapping:

• GPIO0 & GPIO1 -> Rotary Encoder rotation
• GPIO2 -> Button A
• GPIO3 -> Button B
• GPIO4 -> Encoder Shaft Push Switch (Button X)

The driver code lives in the /firmware folder.

BOM