This has to be invented already

such a simple Idea, yet I have never seen it...but it has to be out there right???

Anyways what it is is a phone that can turn from silent to regular mode automatically, I usually remember to turn my phone on silent before classes but afterwards I forget to turn it back on. If I could set it to turn on ring automatically at certian times I could forget about it.

Expanding further on this, a smartphone can incorperate a setting for calendar events such as meetings to each have a specific ring profile.