An LED Ring Light-Enabled Potentiometer

Rotary potentiometers have been used some time to adjust, or “crank up” a given setting — maybe even to 11. A physical mark is usually good enough to tell the rotary status, but in this project, Vaclav Krejci (AKA upir) shows how to enhance a potentiometer knob with coaxial lights that illuminate its position.

The build features an Arduino Uno for processing, along with a breadboard/prototyping shield on top. Lights are provided by a clever ring of 32 yellow LEDs, carefully arranged on top and in the center of the potentiometer knob. LED connections are bent into place on the breadboard, and jumper wires are used to transfer potentiometer readings to the controlling Arduino.

The results are quite nice, with LEDs following the potentiometer position. With a few programming changes, Krejci was also able to get the lights to fill the LEDs up to the this position, which is a neat effect.

This LED display uses traditional — i.e. non-addressable — LEDs, controlled in this case by the Arduino via an 8x4 matrix setup. While driving LEDs in this manner would be impractical in most cases, it allows Krejci to demonstrate how LED matrix control works on a low level. If you’re unfamiliar with this methodology or need a refresher, his excellent explanation can be seen in the first part of the video below.

On the other hand, if you’d rather utilize a driver and save your main IO for other tasks, the video is still a nice intro to this sort of multi-LED rotary display. Components and code are available on GitHub.