Simple Arduino Stopwatch




About: I'm a beginner to Android & Arduino programming And I want to learn and make things.

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.

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Step 1: Parts Required

To bulid this, you'll need-
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

To make its hardware, you need to solder the pin headers to the LCD first and then refer to the official circuit of the LiquidCrystal Display posted in this step or you can follow these steps-

* 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.
10. Enjoy!

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12 Discussions


1 year ago

It is wrong code! Look on the picture at the top of this page => 0h:5m:309s. Place modulo oprator and 60 into lines where you are counting minutes and sconds. Than you will have correct result.

3 replies

Reply 5 months ago

I'm sorry, I don't understand what you mean. Could you please explain what is wrong about the code? I followed every step, but it's not working. Is it because of the 'wrong code' AlexandrB15 is talking about?


Reply 5 months ago

He said that "309s" in the screenshot is because of wrong code which is true. However, the circuit is right and the program is also working. I'll try to update the program to show correct time.

Conor M

2 years ago

Its really nice to see someone looking at improving on my instructable. :-)


3 years ago

Is VCC the same to VDD in the LCD


3 years ago

It's 1600+ views... I can't believe it!!!


3 years ago

Thanks to all for 500+ views.