Adjust Your Volume with theKnob, a Concrete Audio Controller

Concrete and electronics don't meet all that often, but when they do, it usually results in something delightful and unexpected. theKnob, a concrete USB human interface device, is no exception.

"Life is too short to adjust the sound with the mouse and not with a specially designed HID audio control device," says theKnob's creator, and I certainly agree — the more extremely specialized HID interfaces, the better! theKnob is inspired by this project by DIY Perks, but instead of controlling volume with an in-line potentiometer, the creator, BrainHUB Lab, integrated an HID library, allowing it to be seen as a peripheral device when attached to a PC.

Physically, theKnob features a PLA 3D-printed base with a concrete topper. The concrete section acts as a tactile spinner affixed to a potentiometer, and the PLA base contains all the electronics. The hardware is based on a DFRobot Beetle 32u4, one of the smallest Arduino-compatible boards out there, making it compact and easy to program.

Though theKnob's main purpose is volume control and switching, it has a few other features too. Because of the USB-HID library, it can be used for any number of in-application purposes, like as a dedicated scroll wheel. Beyond that, a NeoPixel ring in the base lets it act as a VU meter, giving you a visualizer for whatever music you're listening to.

The team behind theKnob has very thorough documentation that you can use to inspire a build of your own. Check out their 3D-printed parts on Thingiverse, their code on GitHub, and instructions on Hackaday.