Cryptic Wall Clock Inspired by the Mengenlehreuhr Features 96 LEDs in Concentric Rings
The circular device features 52-digit regions, which include a seconds ring, a pair of minutes rings, and two inner rings that denote hours.
Mechatronics and aerospace engineer Troy Hawkins (AKA tomatoskins) has designed a Cryptic Wall Clock that’s both pleasing to look at and confusing (initially) to read at the same time. Hawkins drew his inspiration for his clock from Berlin’s Mengenlehreuhr (set theory clock), which tells time through illuminated color fields, and features 24 lights that are divided into one circular blinking yellow light on top, denoting the seconds, two top rows displaying hours and two bottom rows for minutes.
Hawkins built his clock using 96 LEDs that illuminate 52-digit regions, including an outer seconds ring (in conjunction with the middle dot), with the next two rings indicating minutes, and the final inner rings for repressing hours, which are in the 24-hour format. The LEDs are set in a compartmented circular wooden frame and are held in place with a top board with drilled holes to keep them snug. The face is painted black, and a diffuser and acrylic cover is installed to light up each circle segment.
An Arduino Nano and RTC control the time, while an embedded light dependent resistor and balanced resistor dim the LEDs during nighttime. Reading the time looks confusing at first, but Hawkins explains the method to do so by starting from the inner circles to the outer.
“The inner ring of four fields denotes five full hours each, alongside the second ring, also of four fields, which denote one full hour each, displaying the hour value in 24-hour format. The third ring consists of eleven fields, which denote five full minutes each; the next ring has another four fields, which mark one full minute each. Finally, the outer ring of 29 fields denotes even seconds with the light in the center blinking to denote odd (when lit) or even-numbered (when unlit) seconds.”
For those interested, Hawkins uploaded a well-documented walkthrough of his Cryptic Wall Clock on his project page, complete with required materials, electronics, and code to get up and running.