https://www.hackster.io/kot_behemot53/bluetooth-volume-control-for-an-old-stereo-with-buttons-ba33f0
Bluetooth Volume Control For An Old Stereo With Buttons! - Hackster.io
How about getting rid of that broken volume knob on your stereo and replacing it with some buttons, LEDs and Bluetooth?. Find this and other hardware projects...
bluetooth volume controlold stereo