Need to add a clock function to your next Arduino project? This Real Time Clock (RTC) breakout board kit is your answer. Based on a DS1307 RTC and equipped with an onboard battery and crystal, this kit is simple to solder together, works well, and is easy to use thanks to Adafruit’s online documentation. It’s a great starting point for building your own clock, or even just time-stamping any data your project is gathering.