Now, I will tech you how you can build a simple clock with date, time and day of the week using a 16x2 LCD display and a DS1302 RTC module. The current date and time is stored even after power outage so it will work, for example, when changing power supplies or moving to a different location. Some of the used parts were provided by KUMAN.
Step 1: Parts Needed
Arduino board
9 x Jumper wires
DS1302 module
USB cable
Step 2: Connecting the Components
So, you need to make the following connections:
LCD | Arduino
GND - GND
VCC - 5V
SDA - A4
DS1302 | Arduino
VCC - 5V
GND - GND
DAT - 2
RST - 3
CLK - 4
Step 3: Modifying and Uploading the Code
You can find the code that I've developed HERE. Take a look at the code which sets the date and time (for the first time). You need to modify it, upload the code and then to prevent it from overwritting the date and time which is beeing stored you can either comment-out the 3 lines or delete them. I've explained this in the code as well, using some comments. Feel free to modify it to your likings.