The BeagleBone Black (BBB) is similar to the Raspberry Pi in that it is an ultra-low cost computer. This means that some standard computer features had to be cut out in order to reduce costs. For example, your laptop and computer have a little coin-battery-powered 'Real Time Clock' (RTC) module, which keeps time even when the power is off, or the battery removed. To keep costs low and the size small, a battery-backed RTC is not included with the BBB. Instead, the BBB is intended to be connected to the Internet via Ethernet or WiFi, updating the time automatically from the global ntp (nework time protocol) servers.

For stand-alone projects with no network connection, you will not be able to keep the time when the power goes out. So in this project we will show you how to add a low cost battery-backed RTC to your BBB to keep time!