As part of our large range of convenient modules, we offer a real-time clock module based on the Maxim DS3232 accurate real-time clock IC. The module makes this SMD IC easy to use with any development board that has the I2C data bus, and one of these is the Raspberry Pi.
As the I2C bus can be a little scary for beginners, Matt W from the Australian Bloody Brilliant Blog (!) has documented using this module with an RPi in order to keep accurate time with network time servers. Apart from explaining how to prepare python for the I2C bus, Matt also shows how to scan for the DS3232's I2C bus address and of course set the date and time.
The most important part of any clock project is the inclusion of an accurate 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.