This is some Houdini mathematics here. Mojoptix uses no batteries, no motor, and no electronics to build and operate his Digital Sundials. Instead he 3D prints the time tellers with an intricate, expertly-computed arrangement of rectangular perforations in their ABS bodies that allow only the sun rays that indicate the current time of day to shine through and penetrate the sundial's shadow. Wha-wha-what?!
Mojoptix says the Digital Sundial is "all just a really super-fancy shadow show." When the sun hits a specific time / angle its light shines through the appropriate openings in Mojoptix's carefully laid out design, and projects the current time of day as a digital reading inside the instrument's shadow.
The sundial as a digital clock does have some limitations--it displays time only from 10:00 a.m. to 4:00 p.m., and updates in increments of 20 minutes. But I sure don't care. Mojoptix's use of an awesome high-tech piece of equipment (3D printer) to produce an equally awesome no-tech piece of equipment is brilliant. His mama should have a bumper sticker that says, "My Kid Is an Honor Student at Life."
The Digital Sundial arrives as a DIY kit that includes 4 x 3D-printed elements, a small jar, and 4 x nuts and bolts for assembly. You'll have your choice of color and where you plan to use the sundial (northern or souther hemisphere) at checkout.