There's also quite a difference between programming for Android and programming for a Pi. To your point, there are a lot of cheaper projectors out there that m

There's also quite a difference between programming for Android and programming for a Pi. To your point, there are a lot of cheaper projectors out there that make the particular projector used in the linked post unnecessary. But straight Android isn't going to be the same thing, especially if you can't (or don't) root the device.