Rich WiKi Resources: We provide official Wiki resources, please visit our store and click the wiki page to get resources. Arduino UNO And RTC Module DS3231 This product requires a 3V CR1220 button battery for operation, which is not included. Aazon.co: Waveshare RTC WatchDog HAT (B) for Raspberry Pi, Onboard Precision RTC With Battery Backup Waveshare Precision RTC Module For Raspberry Pi Pico Mini Board, Incorporates High Precision Real-Time Clock Chip DS3231, Uses I2C Bus For Communication, With Female Pin Header Stackable Design Precision RTC Module I2C Comprehensive Timekeeping Features: Tracks seconds, minutes, hours, date, day of the week, month, and year with leap-year compensation, valid up to the year 2100., Flexible Time Format Options: Allows selection between 24-hour or 12-hour formats, with AM/PM indicator. The Pico-RTC-DS3231 is a RTC expansion module specialized for Raspberry Pi Pico. It incorporates high precision RTC chip DS3231 and uses I2C bus for communication High Precision DS3231 RTC Chip: Equipped with the DS3231 chip for accurate timekeeping, including a backup battery holder to maintain time during power loss. Raspberry Pi Pico Compatibility: Standard header design supports Raspberry Pi Pico series, making it easy to integrate with the board.