This is a simple digital clock with embedded RTC (DS1307). The schematic is designed with Microchip microcontroller PIC16F628A. There are two buttons for adjusting the time: One for the minutes and one for the hours.

The time is kept with a small button cell, CR1616 or CR1620. The battery should keep the time set for at least 1 or 2 years if there is no power supply.

• The display is 4 digit/7-segment with digit size 0.56", red color.
• The module should be supplied with exactly 5VDC voltage. The consumption of the module is 30-50 mA.
• This module won't run properly without battery.
• The accuracy of the watch should be the same as that of a typical electronic wristwatch.