Automatic Movie Volume Adjustment
Modern movies, according to YouTuber GreatScott!, are problematic because the speaking volume is often low, while the music is too loud in comparison. Although one might argue this is his opinion, GreatScott! isn’t the only person to have noticed this issue, and decided to do something about it.
His solution is an automatic volume adjusting device. The perfboard-based unit listens to the volume output from his sound bar, and adjusts it up if there’s an extended period of quiet, or down if there is a period of excessive loudness.
This is done via an IR emitter, acting as a sort of automatic single-purpose remote control, without modification to the actual TV/sound equipment.
Onboard the device, GreatScott! is using an Arduino Pro Mini board for processing along with an electret microphone to pick up sound levels.
Two potentiometers provide user input: a deadband pot sets the range where the system does not react to fluctuations, and a react pot sets the time it takes the system to react to out-of-scope volumes.
With this setup, a single clap or similar suitably short loud sounds can be experienced without adjustment, while extended quiet or loud segments are suitably normalized. You can see his explanation in the video below.
A circuit diagram for the build, as well as code and a parts list is available in the project's write-up.