Use DS3231SN precision clock chip, built 32.768 crystal

Can provide precise year, month, day, hour, minute, second, in the morning and afternoon data

You can output 1Hz signal, a second output signal

You can use the CR1220 coin cell holding travel time

The pull-up resistor R1 R2 own welding on the I2C bus

Small size 3cm in diameter

Pin spacing 22.86mm

Weight 0.1 kg
Dimensions 20 × 15 × 5 cm