Great solution for teachers that need to be mobile in the classroom and still be able to control the projector & AV system that is connected to your teacher computer:  

You can remotely access your Windows Computer using Chrome Browser by installing the Chrome Remote Desktop "App" on the PC. Then install the appropriate CRD app for your mobile device. See the following article on how to do this for each device.   

Read the Google "How To":  How to install Chrome Remote Desktop - For Windows, MAC, iPad, Android (Computer, Tablet, Phone).