The build relies on a 20×2 character VFD display that looks ... The Arduino Nano inside takes in the audio signal via its analog inputs. It then processes the audio with the fix_fft library, ...

There’s no shortage of clock projects, but [niq_ro] has his own take using a vacuum fluorescent display (VFD), and Arduino, and a pair of MAX6921 ICs. Those chips are made to drive a VFD, and ...