Project is not available for free download! If you are interested in purchasing the software part of the project with the functionality described on the given page, contact: martinius96@gmail.com
Arduino LCD Stopwatch Firesport Schematics Code Eagle

Stopwatch for fire sport through Arduino


  • I have to guess every village or part of the city.
  • Every week, especially during the summer season, village competitions take place and teams score valuable points, achievements and failures, which are also decided by one hundredth of a second.
  • My stopwatch implementation uses millis, an internal Arduino timer that returns milliseconds since the processor started.
  • So we can measure the time to 2 decimal places, ie perform timing every 10ms, which is 0.01 seconds.
  • The problem, however, is the speed and limits of the I2C bus, the display itself, and of course the program calculations.
  • The system logic is performed every 10 or 100 milliseconds, depending on the software. (10 milliseconds - accuracy to 100ths, 100 milliseconds, transmission to tenths of a second)
  • The stopwatch has a 32-millisecond display problem. Since Arduino is not a multi-core processor, 3-hundredths are skipped. Can't do 2 things at once.
  • Therefore, I recommend that you only display the display once per second, or at action (stopwatch, clear time).
  • System functionality:

  • Stopwatch is started by a button (it can be replaced by a signal gun, the second button can stop and reset the time.
  • 2 make contacts located on the targets are activated when the target falls, stopping the left / right current on the stopwatch.
  • The last button is used to reset the time - reset the time, new team.
  • The stopwatch cannot in any way replace a certified stopwatch!

    What does the project use from the technical (hardware) side of the project?

  • Arduino Uno, or a separate AtMega chip (Scheme is compatible for Arduino Uno, Nano, Mega)
  • 16x2 or 20x4 LCD display with I2C converter
  • 2 buttons
  • 2 make contacts
  • Due to multiple source theft and unauthorized author changes, the source code will no longer be available!

    Stopwatch in action:

    Stopwatch to one hundredth of a second Stopwatch for tenths of a second

    Lib (I2C) LCD 16x2, 20x4

    Schéma zapojenia (Eagle):

    Schéma zapojenia pre hasičské stopky - Arduino