This "instructable" will show and teach you how to make a simple Arduino Uno clock that also acts as a stopwatch in just a few, simple steps.
Step 1: Gather All Necessary Materials
To start creating your Arduino Uno clock/stopwatch, you should have an Arduino Uno, a DS1307 Real Time Clock Assembled Breakout Board, a SainSmart 20x4 IIC/I2C/TWI LCD Module, a full sized breadboard, an Arduino pushbutton, a 10k ohm resistor, male to male jumper wires, male to female jumper wires, and a USB Type A Male to USB Type B Male cable. You are also going to need a computer with the Arduino IDE software installed.
Step 2: Connect the Wires, Button, and Resistor
In order for the Arduino Uno, the SainSmart LCD2004, and the DS1307 Real Time Clock Assembled Breakout Board devices to communicate with each other, you must first connect the DS1307 Real Time Clock Assembled Breakout Board, Arduino pushbutton, and 10k ohm resistor to the full sized breadboard at certain points on it (use schematic for points). Finally, you will need to connect all of the jumper wires between everything at certain points (use schematic for points).
Step 3: Get the Code
Now, to get all of the devices that are connected to each other actually communicating and act as a clock/stopwatch, we will get the code that will tell everything to do exactly that. To get the code, all you have to do is download the attached file that is labelled "clock.ino", launch the Arduino IDE software on your computer, and open the "clock.ino" file (more detailed instructions on this process are attached as images).
Step 4: Connect the Arduino to a Computer
After writing all of the code for your Arduino Uno in the Arduino IDE software, connect it to your computer with the USB Type A Male to USB Type B Male cable, with the USB Type A Male going into the computer USB port and the USB Type B Male going into the Arduino USB port. The Arduino Uno should now be connected.
Step 5: Upload the Code
Now, all that we have to do at this point is upload the code to the Arduino Uno and the clock/stopwatch program should begin working as long as the Arduino is properly connected to the computer and everything else is connected in the right places. To upload the code to the Arduino Uno, just click on the "upload" button in the Arduino IDE software.
Step 6: Use It
Once the code is all uploaded to your Arduino Uno, the clock should automatically begin on the LCD display. You can start the stopwatch by pressing the button and stop it by pressing and holding the button for a second. That's all!