Clocks normally tell you the time in your particular location, but what about that person that you know across the country or even on the other side the world? What time is it there? While it’s easy enough to do a web search or do a calculation, in order to find this out at an instant, Jeremy Cook made his own mechanical dual time zone clock.

The device is powered by an Arduino Nano, which drives a stepper motor to advance each minute. Using physical gear reduction, dual hour gears move at 1/12th the rate of the minute indicator gear, which can be offset to the secondary time zone of your choosing.

A real-time clock module is implemented to trigger each stepper advance, and a single button fast forwards the assembly when needed. Code, while still in a somewhat experimental state, is available on GitHub.