We love the design of this calculated doom clock, and it’s quite simple inside — an Arduino Pro Mini outputs the graph on an 2.9″ e-paper display, and both are powered with a 5.5 V solar panel.

It runs on an Arduino Pro Mini knockoff and an RTC module for the sake of simplicity. [Lee] chained NeoPixel strips together in five rows of eight, which allowed him to use a 3×5 font to display ...