Binary Clock

Created: 2021-05-30

A wall clock that tells time in binary-coded decimal. The styling is inspired by old SciFi movies. Each column of orange lights is a decimal digit, the white light indicates PM. In the picture, it is 6:47 pm.

The Matrix

The digits are made of 5mm yellow/amber LEDs, the PM indicator is a white 3mm LED. They are in 3d-printed plastic diffusers of the same color, with aluminum tape on the back to reflect more light forward. All of the LEDS are wired in a matrix. Two of the LEDS for hours are missing in this picture because I only thought of 2 (12) as the maximum, not 9. I fixed that later. The tens of minutes only goes up to 5, so the top LED of that column is correctly ommitted.

The Rest

The matrix is driven directly by an Adafruit ItsyBitsy with a Sparkfun RTC module. The time is initially set over serial, the same as my LED watch. The RTC then keeps the time accurately for quite a while, with battery backup. (I haven't had to set it again after a couple months.) The clock is powered by a Pi 3 power supply plugged into a panel-mount USB jack on the bottom. The boards are just floating, wrappped in electrical tape so as not to short out against the matrix. The panel-mount cable holds them in place. The case is printed in multiple pieces:

The face, in matte black PLA.
Two identical sides, in bamboo PLA.
Two more identical* halves, the top and bottom. The bamboo PLA started clogging my nozzle, so I did the bottom in silver PLA.

*The bottom has the mounting point for the USB connector, so it is a little bit different. The half pieces snap together, and are held in place by M3 screws that mate with threaded inserts in the face. The back pieces have posts for additional threaded inserts, meant for a back cover. However, I decied not to bother, and to just hang the clock on the wall by the top center post.