A Modular Macro Keypad

What happened

The introduction of the ATmega32U4 microcontroller, with its integrated USB controller, made a lot of hardware tasks much simpler than they were before. The suutari20, as it is called by its creator [Squalius] is able to achieve these aims by using 3.5 mm jacks commonly found in audio equipment.

One of the arenas it revolutionized was custom keyboards, making it much easier to build not only standard mechanical keyboards, but keyboards of all kinds of shapes and layouts and custom macro keyboards as well. Each jack can support up to three keys, with the hub ultimately able to support 18 different keys.

Those can include analog devices as well, such as volume knobs or jog controllers. From there, all that’s needed is a case, in this example a 3D printed one, and the commodity audio hardware to plug everything in to.