An Arduino Stopwatch made from an existing LiquidCrystal library example - Hello World. It shows you the time passed since reset. This instructable is inspired by the instructuble created by Conor M - Arduino Stopwatch. I stripped down the code and made this super simple and light.
Step 1: Parts Required
1. A PC with Arduino IDE installed
2. An Arduino or any Arduino-compatible board, most preferably, an Arduino Uno.
3. An LCD with or without backlight.
4. Few jumper wires.
5. A breadboard.
6. A USB cable to connect your Arduino to your PC.
If you lack any of these parts, then please look for it on any online/offline electronics hobby store.
Step 2: Building Stopwatch's Hardware
* LCD RS pin to digital pin 12
* LCD E or Enable pin to digital pin 11
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* LCD R/W pin to GND ( ground )
* LCD VSS pin to GND ( ground )
* LCD VCC pin to 5V
* LCD V0 pin to GND ( ground )
Note that in the circuit diagram there a Potentiometer has been used, but that's not necessarily required if you don't want to control the contrast and also it creates problems for the beginners.
Step 3: Bulding Stopwatch's Software
To program your Stopwatch, you'll need to-
1. Install the official Arduino IDE from the Arduino website.
2. Download the Stopwatch sketch or the source code.
3. Open the IDE.
4. Go to Files -> Open or press Ctrl+O
5. Open the sketch.
6. Now your sketch will load.
7. Go to Sketch -> Upload or Click on the arrow icon below Edit menu and next to the tick icon. This will upload the sketch to the Arduino.
8. Now it's done.
9. While keeping the cable connected to the PC, press the RESET button on the Arduino. This will use up the power from your PC.