We've seen quite a few cool clocks made with our products over the years. We even have one of our own proudly displayed right by reception! But this project from from SparkFun customer Matt Keeter is one of the best we've seen. Check it out!
Matt's Slideclock uses two motorized slide potentiometers and a custom-designed PCB based on an ATMega168 microcontroller. Matt designed the PCB in Eagle which uses an H-Bridge for motor control, a 32.768 KHz clock crystal for timekeeping, an LED, and various other parts.
Matt designed the board so the microcontroller can be programmed through the on-board SPI header. There is also an FTDI header for debugging/serial communication and a five-pin header to connect to the slide potentiometer. He also put some useful features into the firmware for his clock, most notably a power-saving sleep mode where the microcontroller spends most of its time. Timer2 interrupts the sleep every second to keep the time accurate.
Matt designed the case in CAD and cut it out of some scrap wood using a laser cutter. The one hiccup he ran into during his design was that he forgot to include a voltage regulator on his board - which he solved via a pretty darn clever modification to his battery plug that you can see above.
The final result is impressive! Check out Matt's website for more information on this project as well as some of his other designs. Great job!