A square object hanging on a wall. It has curved beige sides and a black face. The face is covered in a grid of orange squares, and one white circle. Some of the orange squares are lit up.

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 back of the clock, showing the backs of LEDs inside plastic diffusers, with their leads connected in a grid pattern.

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 back of the clock again, with more parts added: deeper walls, a circuit board wrapped in electrical tape, wires, and a cable mounted to the bottom.

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 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.

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