Another intereresting and different form of clock has been made possible, and demonstrated by enthusiast Alexander Lang with his "knock clock". The clock operates in a similar manner to an older clock with a gong, in but instead the Arduino will control a solenoid mounted inside an enclosure - and use that to "knock" the side over certain intervals to indicate the time.
The circuit is a typical Arduino-compatible ATmega328P microcontroller with a real-time clock IC and a MOSFET to control the higher voltage required for the solenoid. You can see the operation of the solenoid in the following video:
As well as an interesting clock, Alexander's series of articles demonstrate making a PCB at home and quite a few design considerations which can be useful for the beginner or enthusiast alike - so to get started, visit the first project page. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're wanting to make your own Arduino-compatible clocks or other off-board projects, you'll need an ATmega328P MCU with Arduino Uno bootloader:
This is the same Atmel AVR ATmega328P microcontroller used in the official Arduino Uno, as well as our Eleven, EtherTen, USBDroid, and other boards. Perfect for building your own Arduino-compatible project directly on a breadboard or on a custom PCB, or for replacing the MCU in an existing board.
It comes with the Arduino Uno bootloader pre-installed and has a special label stuck on top with details of the pinouts, so you don't even need to look up the datasheet when connecting it up in your project! For more information and to order, click here!