Using an Apple TV (at the time of this post, Feb 2015) can be somewhat tricky in our schools. The only way they work currently is to connect the device via ethernet (not wireless*) to the Admin network (not the Student network**). This will allow the teacher/staff to broadcast their screen from their BCBE issued Macbook to the projector/TV. This will not allow students to project from their laptops, as they are not on the Admin network.
(This post was updated on Sept 14, 2015 to also include Chromecast. Chromecast devices will not work for the same reasons outlined in this FAQ.)
* The Apple TV does not allow the type of authentication required by our wireless admin network, which necessitates the ethernet connection. Ed Tech does not install new network drops to accommodate these devices.
** If connected to the student wireless network, there is no way to control which student projects their screen, or what they project. Connecting to the student wireless is therefore not allowed.