Instructables user 'Emacheen22' has started making things with his Arduino and has documented his binary clock. In this version of the Arduino users' rite-of-passage, he has fitted the LEDs inside a classic "Connect 4" game vertical board, so as to illuminate pieces in the board with LEDs. For example:
Although a simple project it's a good one for the beginners or those short on time but needing fast results. To get started with your own visit the project page here. And we're on twitter and Google+, so follow us for news and product updates as well.
Many beginners fall into the trap of making their own clocks and relying on the Arduino's internal timing systems - then become unhappy due to the lack of accuracy. This can be avoided by using a real-time clock IC. Here at Freetronics we have the Maxim DS3232 real-time clock IC module:
Apart from keeping accurate time for years due to the temperature-controlled oscillator and having a tiny coin-cell for backup, it is very simple to connect to your Arduino project. A driver library allows your program to easily set or read the time and date. Perfect for clock projects, dataloggers or anything that needs to know the date and time. Furthermore it contains a digital thermometer and 236 bytes of non-volatile memory to store user settings and other data. For more information, check out the module page here.