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
- 1 x Arduino Nano (or similar)
- 1x MAX7219 LED Display (8 Digits x 7 Segments)
- 3 x Push Buttons
- 1 x Breadboard (half size)
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
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:
- LedControl.h(Arduino library for the MAX7221 and MAX7219)
- 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
There are three push buttons with the following functions:
- Reset the display (1st switch on left)
- Start / Stop the Stopwatch (2nd switch at middle)
- 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.