Tape your iPhone headphone controller to the carrier, adjust the carrier position with the knurled nut so the cam just hits the + button, set the turntable on top, aim your iPhone at the subject you place in the center and turn the crank. One complete rotation of the turntable equals 30 exposures- I use the free version of 3df Zephyr to build a 3d model from these.
I'm just starting out 3d scanning with photogrammetry, and I really, really wanted to like the $30 3D scanner (https://www.thingiverse.com/thing:1762299). Unfortunately, it has some problems, and after trying to fix one after another I decided to scrap it and start from scratch with my own design.
The turntable's weight is supported by four rollers, and the drive is by worm gear, so no more skipping teeth or rocking with lightweight subjects. The iPhone headphone control holder is easily exposed and has an adjustment nut, so you can fine-tune the cam pressure without tearing the whole thing down or making a bunch of shims. I didn't include an iPhone stand, since there's no shortage of excellent designs already out there. According to S3D, using $25/kg filament the whole thing cost $3.47 to print.
Update 2/11/2018: Just added one piece turntable and frame STLs for folks with large printers. For folks printing the two-piece versions, my dovetails are friction fit and shouldn't require glue, but they're directional- make certain you're snapping the small part down on the large part, not the other way around.
Update 2/22/2018: Per request, just added turntable and frame versions to allow printing on very small printers (110mm diameter). For the frame, print TinyFrameA, two of the existing FrameB, and one each TinyFrameC and TinyFrameD. For the turntable, print TinyTurntableA and six TinyTurntableB. As always, place the male dovetail over the female and press together, not the other way around.