The Apple TV unit is a must for any classroom using iPads. The ability to share screens via AipPlay with others makes teaching and learning a far more communal experience, and at $99 it is just too good to pass up.
Unfortunately, most classroom are not equipped with a brand new HDMI enabled video and audio inputs that exist on the Apple TV as the majority still utilise VGA data projectors.
Many teachers in this situation who have purchased an Apple TV are somewhat disappointed, as they sacrifice functionality or mobility in an effort to project iPads to the big screen due to the incompatibility of new and old technology.
Yes, there are multiple alternatives to get around this but if you want high quality video, and audio to your existing old school speakers and full wireless mobility then this is the easiest and cheapest solution that just simply works.
The Kanex ATV Pro adapter is the ultimate solution to this problem offering full functionality with a traditional VGA projector and also enables audio through a standard headphone jack. This device will also allow you to work wirelessly.
There is no power required, and at under $50 it is an essential item for any classroom in this situation.
I have installed this device in a number of schools. It takes minutes to setup and you can forget about it from there on in and just get on with teaching.