Stereo audio precision rectifier and envelope follower for VU meters or other low-frequency AC signals. Can be used to directly drive meter displays or with an ADC and a microcontroller. Eagle and PDF files are available at:

https://github.com/n0mjs710/Stereo-Audio-Dectector-v2

Part of a larger project for a complete stereo VU meter with 32 LEDs per channel that also includes:

Code:

https://github.com/n0mjs710/Stereo-VU-AVE-PEAK-Teensy

Display Board:

https://github.com/n0mjs710/Stereo-VU-Meter-v2

https://oshpark.com/shared_projects/fC6WZwjg