Smart Endoscope is a free Android app created by GrusIoT that connects to a camera. It supports both Wifi and USB cameras, and allows the user to take photos and record videos which can be viewed and shared in the system album. One of the most useful features of this app is its full-screen mode and Angle rotation, which is helpful for a variety of situations.

It's important to note that for Android 9 and later, users need to grant camera permissions to fully access USB video devices. However, the app does not include any functionality or code to access the built-in camera, as it's not necessary. Overall, Smart Endoscope is a handy tool for those who need a camera app with additional features such as Angle rotation and full-screen mode.