Unity AR targets to Android and iOS. Are there single board devices that will run the custom apps created as if the device was a cellphone?
The device does not have to make calls, just run the application build with no adjustments.
The single board computer would attach to screen, camera, mic to run demos created in unity.
Lots of single-board computers support android in their BSP. It's often less porting effort than Ubuntu since the SoCs generally have mobile as a primary market. If you need it, this can give you more processing power than the more common Raspberry Pi 3. For example, the LeMaker HiKey which is an 8 core A53 with up to 2GB of RAM. Other options worth looking at to get a feel for the market are the generic Android TV boxes. The HiKey board I linked seems to have launched about 2 years ago, there will be newer options too.
You could potentially install Android 7 on a Raspberry Pi 3 if you wanted to run that, as described by the MagPi magazine.
The binaries can be downloaded here, although I can't tell if the performance will be that great, or if it will be sufficient to run an AR application. You might just be able to use a USB camera (according to this discussion) although there's no definitive documentation as to which devices work and which don't.
There are some reports that microphones don't work all that well, and sound is known to be a problem, but it may have been fixed in the more recent versions.
If you're more interested in making the Raspberry Pi run iOS, you're out of luck—Apple are not at all keen for people to run their software on non-Apple devices.
