How do I notified when camera is used or opened by any other application

I want to get notified whenever any other application opened or accessed camera. I already know that I can check Camera.open() and its exception. but for that I have to check every time using service but it drain battery so I want whenever opened camera just notified me and get its package name. I already read these.

How to find whether the camera is in use?

How to check if camera is opened by any application