Introduction: Stopwatch and Lap Time Counter

Picture of Stopwatch and Lap Time Counter

Hello all,

This is a very easy project to be done about a stopwatch using Arduino Nano and MAX7219 LED display (8 Digits x 7 Segments).

The stopwatch using this kind of display is new and I could not find anything like it.

The first 4 digits of display show the time count and the last 4 digits show the lap time and the maximum time count is 999.9 seconds (16 minutes & 39.9 seconds).

Take a look on Video.

Let's see it !!

Step 1: Material List

Picture of Material List
  • 1 x Arduino Nano (or similar)
  • 1x MAX7219 LED Display (8 Digits x 7 Segments)
  • 3 x Push Buttons
  • 1 x Breadboard (half size)
  • Wires

The MAX7219 is very simple to be used and you need only 3 data pins to connect to Arduino.

With this configuation using the Arduino Nano, we have a more compact package.

Step 2: Schematic

Picture of Schematic

The assembly of components is very simple.

Just follow the schematic with care about wiring connections.

Step 3: Programming

The program was developed for Arduino Nano but you can use it for Arduino Uno too.

You will need to include in your Arduino two libraries:

  • Bounce2.h (Bounce is a library for Arduino. It debounces digital inputs and more.)

Note: With minor changes you can adapt this program to ATtiny85 microcontroller too.

Step 4: Using

Picture of Using

There are three push buttons with the following functions:

  1. Reset the display (1st switch on left)
  2. Start / Stop the Stopwatch (2nd switch at middle)
  3. Show the lap time (3rd switch on right)

The running time in tenths of seconds is shown at first 4 digits on left of display.

The lap time is shown at last 4 digits on right of display.


If you want, it is possible to change the Start/Stop and the Lap time buttons for sensors like LDR, for example, to giving you an automated way to control the stopwatch.


Odilond (author)2016-07-25
  • 1x Maxi 7219 LED Display (4 Digits x 7 Segments)???
  • 8 Dígitos x 7 Segments
lagsilva (author)Odilond2016-07-25

8 digits X 7 segments.
Tks for warning!

About This Instructable




Bio: I'm a Mechanical Engineer and an enthusiastic Maker. I like to create and code my projects using the Arduino.
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