Eptaora, an Electromechanical Cam Clock

Time is the thing that keeps everything from occurring at once... is a quote that I’m likely half-remembering, but as such we need a way to coordinate our actions according to this fourth dimension. Smartphones are the easy solution, but if you want to show things off in 3D-printed electromechanical style, then the seven-segment Eptaora clock from Ekaggrat Singh Kalsi could be your next timepiece.

Eptaora employs a system of cams driven by two 15mm geared stepper motors (one for hours, another for minutes) to pop each of the needed 7-segments up in order to display the appropriate digits. The device is controlled by a Microchip ATtiny84 processor, as well as two A4988 driver boards. Hall effect sensors keep the apparatus on track, though without a precision timekeeping device, it would likely need to be reset fairly often. Perhaps that's an upgrade someone integrate in a future revision.

As shown in the video below (along with some sharp renderings), it’s a fantastic device from a mechanical standpoint, with a satisfying cam lifter motion, and a carryover gear that appropriately links the first digit to the second in each set. Several prototypes of the Eptaora were made, including a larger setup to help understand the motion, and an all-in-one unit that used only a single stepper (but was painfully slow to adjust).

Files for the build are available on Thingiverse, which looks like a great reason to keep your printer running for the next few hours and/or days!