This in this lesson we have 7 projects in one. We learn how use DS1307 Real-Time Clock (RTC) module to build a clock using Arduino. This is project 6 LCD Clock using DS1307 RTC module. We learn how to display a full calendar and clock on LCD1602 or LCD2004 LCD display. We use LCD screen with the I2C module wich allowes us to have only 4 wire.