These are great battery-backed real time clock (RTC) that allow 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). The PCF8523 RTC can run from 3.3V or 5V power & logic!
Works great with an Arduino using our RTC library or with a Raspberry Pi (or similar single board linux computer).
- PCB & header are included
- Plugs into any breadboard, or you can use wires
- Two mounting holes
- Will keep time for 5 years or more
Note: These products do not come with a CR1220 coin cell battery. We recommend you purchase a coin cell battery to use with these products.
The PCF8523 and DS1307 are simple and inexpensive but not high precision devices. They may lose or gain up to 2 seconds a day. For a high-precision, temperature compensated alternative, please check out the DS3231 precision RTC.