Before LCD, OLED, and other similar displays were extremely cheap, we had electromechanical flip clocks, which cycle through a series of numbers marked on their own individual flaps. While still available, either for purchase or as hacked devices, it seems that the flip clock concept has come full circle with Mark Wilson’s project.
Instead of physical flaps, Wilson’s unit simulates this movement with a three-step animation, revealing pictures of the flaps progressively tumbling down to their lower position. Additionally, it features a blinking colon, date display, and even shows days until the trash or recycling needs to be taken out (in red or yellow depending on the situation), likely impractical on an actual physical build.
Code for the device is quite involved, taking up all but about 100 bytes of the Arduino Uno used to power the display. Programming includes several “bonus” faces, such as a CubeClock, TriangleClock, and a PongClock, and more details can be found in Wilson’s write-up as a .zip file if you’d like to create your own.
Two buttons set the time and date, as as well as the face on display, and one can even configure it to randomly cycle through faces. A DS3231 RTC module takes care of proper timing, and the physical build itself is fairly simple, consisting of the screen, Arduino, and interface shield, along with a minimal enclosure made of standoffs and front/back acrylic plates.