This Arduino Extender Box Adds a Joystick and Rotary Controls to a Keyboard

I frequently extol the virtues of good keyboards here on Hackster, because I very firmly believe that your keyboard can dramatically affect your comfort when using a computer. Because of that, we often feature custom keyboard builds. These are often mechanical keyboards with high-quality key switches and that integrate many interesting features. But not everyone wants to deal with the expense and effort of creating a custom keyboard. Maybe you like the keyboard you already have and just want to add a bit of extra functionality. That’s the scenario Bradgrier’s Arduino Extender Box is designed to address.

This is a small auxiliary controller that attaches to the top of an existing keyboard. It contains a joystick and four rotary knobs. Bradgrier built it to provide an extra control interface for video games and flight simulators. The knobs can be used to adjust and mix volume while in a game, so, for instance, the master volume can be controlled independently of team chat volume. The joystick can be used for all sorts of controls, like a plane’s throttle in a flight sim or camera panning in a city builder game. Bradgrier obviously designed this box to fit onto to his keyboard, but the design is universal enough that it should fit pretty seamlessly with a wide range of keyboard models.

The heart of this controller is an Arduino Pro Micro board. The joystick is an Arduino KY-023 module, which is based on a biaxial potentiometer and has a switch when pushed down. The four rotary knobs are simple potentiometers. Aside from the cables and wires, the only other components are a standard resistor and a 5mm red LED. All of that hardware is housed within a simple, but attractive, 3D-printed enclosure. The code running on the Arduino is programmed to work with deej, which is open source hardware volume mixer software that is compatible with both Windows and Linux computers. That takes care of the knobs, but the joystick requires a separate library that makes the Arduino show up as a standard USB HID controller. That works with most PC games so you can assign functions to the joystick. If you want to expand your existing keyboard’s capabilities, this seems like a great choice.