Adafruit DS1307 Real Time Clock Assembled Breakout Board Category_Radio & Wireless/RF 84 & 84) are called

84 & 84) are called "Real" because they perform a complete ranging

The use of advanced digital filtering technology can effectively reduce measurement noise and improve accuracy

B and B+ Raspberry Pi's

It's a truly flexible logger

Adafruit DS1307 Real Time Clock Assembled Breakout Board Category_Radio & Wireless/RF 84 & 84) are calledThis is a great battery backed real time clock (RTC) that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. Perfect for datalogging, clock building, time stamping, timers and alarms, etc. The DS1307 is the most popular RTC but it requires 5V power to work (although we've used it with 5V power and 3. 3V logic successfully) Works great with an Arduino using our RTC library or with a Raspberry