I guess something is in the air, because this is the second DIY kit I've written about this week. Today I'd like to point your attention to the Mojoptix digital sundial kit.

What this amazingly clever, 3D-printed sundial does is use precisely-cut holes to display the time in its own shadow, digital-style. Here's how they describe it:

No batteries, no motor, no electronics... It's all just a really super-fancy shadow show. The shape of the sundial has been mathematically designed to only let through the right sunrays at the right time/angle. This allows to display the actual time with sunlit digits inside the sundial's shadow.

The sundial displays time (with actual digits !!) from 10:00 until 16:00, updating every 20 minutes. You can precisely adjust the displayed time simply by rotating the gnomon (the magic box that displays time). So you can even adjust for Daylight Saving Time.

In this YouTube video they describe how they came up with the design of the sundial:

The bit about how the sundial can be adjusted at certain angles to work anywhere on the planet is actually quite fascinating. If you want to skip all that and get to the part where you see it in action, that's at the 13:04 mark.

If you happen to own a 3D printer, you can download the source files at Thingiverse. If not — or if you'd just rather buy the thing premade — you can buy the kit on Etsy for $79 USD. All you have to do in that case is take the four 3D-printed elements and assemble them onto the included small jar with the also-included nuts and bolts.