Arduino VU meter

I wanted to implement a VU meter in an amp project I’m working on. There are several dedicated IC’s out there like the famous LM3915, but I already had an Arduino (AtMega 328p) on board for some other tasks. Why not use that! More fun and saves an IC.

There are several examples of Arduino driven VU meters floating on the net, but with respect to those fun and educational DIY projects, they don’t pass as a proper VU meter. Very jumpy, nervous, linear scale, no peak hold and only half the waveform resolution (more on that later). To get it as functional and ‘good looking’ as the LM3915, some hardware and software additions have to be made.