"This is the XXI Century Sundial, created by Alessandro using an Arduino microcontroller, a wall, and a laser.
This is a simple project of a sundial wherein the pinion is replaced by a line LASER I took from a LASER level. The LASER is mounted on a RC servo which in turn is driven by a micro controller. The micro controller keeps the time and turns the RC servo accordingly. ... Shorting pins 1-2 adds some life to the sundial and makes it count just the seconds. Hypnotic initially, then pointless.
Originally put together using an Atmel controller, it is "very basic in design it does exactly what I wanted," Alessandro writes."
XXI century sundail -- Now for Arduino also ! [5volt via Make]