A more recent phenomenon, the "Word Clock" consists of a large square face, with a printed cover that has all the words required to articulate the time in speech. Behind each word (or letter) is an LED, and when illuminated in the correct sequence, the time in words is displayed on the clock. Furthermore various effects can be created as you also have a large LED matrix to experiment with. One great example of a word clock has been demonstrated by Arduino forum member "Riva", who offers the following demonstration:
The circuitry behind the clock isn't that complex, mainly due to the use of two MAX7219 LED display driver ICs to take care of all the LEDs. And if you want to make your own, Riva has published the sketch, schematic and a template so you can print your own cover as well. For these files and discussion, log in to the Arduino forum. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
When making your own clock - don't skimp on timing accuracy - instead, consider using our real-time clock module based on the DS3232 - with a temperature-controlled oscillator it is highly accurate, and has an onboard backup battery for when the power dies and 236 bytes of non-volatile memory for user data.
It's easy to use with almost any platform due to the I2C interface, and we've got tutorials for both I2C and using the Arduino library. To learn more and order, visit the RTC home page.
