Driving a clock with a microcontroller, Arduino or otherwise, may seem overkill when a simple timer circuit is enough - but when you're building a clock as unusual as Danté Roumega's latest creation, it makes a certain twisted sense. Where a traditional clock moves hands over a fixed face, Danté's version moves the face behind a fixed hand.
Danté's clock, while not the first based on the design, is a great introduction to crazy clock design: a stepper motor and controller are connected to an Arduino Micro, and linked to a cardboard wheel with a 72cm circumference. By programming the Arduino to drive the stepper motor in such a way that the outside edge of the wheel moves at 1cm every ten minutes, the clock completes a single rotation over a twelve hour period - just like a traditional analogue clock. A strip of paper marked with one-centimetre ten-minute intervals and a fixed-position pointer to indicate the current time finishes the build, which is certainly better suited to sitting on a desk than being mounted on a wall.
The Arduino is surprisingly popular for these types of projects, given that most variants don't include an integrated real-time clock (RTC) module: we've seen impressive Grandfather clock rebuilds, smart internet-connected alarm clocks, and even false sunrise clocks for children alongside more esoteric measurement tools like Joe Bembridge's population infographic project.
Full instructions on how to build a clock like Danté's are available from the Instructable page.
Today I'm going to show you how to build a very different looking clock, powered by an Arduino. The idea behind the clock is a circle with a circumference of 72cm (28.3465 inches) that ticks at 1cm every ten minutes which means every 72 ticks will equal 12 hours making it a 12 hour clock.