“Today we are going to build one of the most important tools in sound mixing; A audio VU (volume unit) meter based on an Arduino/AVR microcontroller. This project serves to demonstrate how the knowledge of electronics can be applied to build solutions for any part of your day to day life.
A volume unit (VU) meter or standard volume indicator (SVI) as it’s sometimes called, is a device which displays the audio signal level of an audio signal. It is essentially a basic voltmeter (fitted with transducers to convert sound to voltage) that takes a simple average of the signal and displays it with an attack and release time of around 300 ms. It was originally designed as a kind of loudness meter, rather than as a peak meter, but it is generally used in audio recording to help make sure you’re recording at appropriate levels.
Today’s version of the project is based on a project started by Adam Ples on Github and it uses AVR ATMega88/168/328 (and ATMega48 if possible) which makes it compatible with Arduino boards like the Uno, Nano and Due. For the display, the project was designed to be compatible with small (and cheap) monochrome OLED displays based on the SSD1306 or SH1106 driver.
The goal of this version of VU meter include:
To achieve a 2-channel operation,
Accuracy to be as close to real VU-meter specification as possible,
high FPS, 60+ — no visible jumping of the needle, as is common in other designs.”