A board hosting an ATtiny85 MCU and two potentiometers, typically used as a minimal sound generator.
In this repository you can find the schematic and the production files.
The building is straightforward, the LED will light up accordingly to the output signal.
Since I'm using a PWM output, depending on the board application, a passive low pass filter can be customized by choosing the values for R and C components, i.e. a 1K resistor and a 100nF capacitor will lead to a cutoff frequency of 1591.54Hz.