DIY Micro:bit Digital Stopwatch: Fun Coding Activity (2026)

DIY Micro:bit Digital Stopwatch : Overview

The DIY Micro:bit Digital Stopwatch is an engaging STEM project that helps students learn programming, electronics, and time measurement using the BBC Micro:bit. A stopwatch measures time accurately for sports, science experiments, classrooms, and daily activities. Using Microsoft MakeCode, students program Button A to start, Button B to stop, and A+B to reset the timer. The LED display shows the elapsed time. Through this activity, students learn variables, loops, conditions, timers, and event-driven programming while understanding how software controls hardware. The project also encourages creativity by allowing students to extend the stopwatch with sounds, countdowns, or lap timing. It provides an excellent introduction to embedded systems, computational thinking, and engineering design.     

Innovation

Transforms the Micro:bit into a programmable digital stopwatch using block-based coding.

Materials Required

BBC Micro:bit, USB cable, Battery pack, Computer, Microsoft MakeCode, Micro USB cable.

Learning Objectives

Learn variables, loops, timers, event handling, and embedded programming.

Working Principle

Press A to start, B to stop, and A+B to reset. The LED matrix displays elapsed time.

Detailed Step-by-Step Procedure

Step 1: Connect the BBC Micro:bit

Connect the BBC Micro:bit to your computer using a Micro-USB cable. The device will power on, and the 5×5 LED display will light up. If you have a battery pack, you can connect it later to make the stopwatch portable.

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Step 2: Open Microsoft MakeCode

Visit the Microsoft MakeCode for Micro:bit website and create a New Project named Digital Stopwatch.

The MakeCode editor provides a block-based coding environment where programs can be created by simply dragging and dropping coding blocks.

Step 3: Create Variables

Click Variables → Make a Variable.

Create the following variables:

• time 
• running 

Initialize the variables as follows:

• time = 0 
• running = false 

Step 4: Initialize the Stopwatch

Inside the On Start block:

• Set time = 0 
• Set running = false 
• Display 0 on the LED screen 

Step 5: Program Button A (Start)

Add an on Button A pressed block.

Inside it:

• Set running = true 

Step 6: Program the Timer

Inside the Forever block:

• Check whether running = true 
• Pause for 1000 milliseconds (1 second) 
• Increase time by 1 
• Display the updated value 

Step 7: Program Button B (Stop)

Add an on Button B pressed block.

Inside it:

• Set running = false 

Step 8: Program Button A+B (Reset)

Add an on Button A+B pressed block.

Inside it:

• Set running = false 
• Set time = 0 
• Show 0 on the LED display 

• Multiple Button Events 

Step 9: Download the Program

Click Download.

Copy the downloaded .hex file to the connected BBC Micro:bit.

The Micro:bit will automatically restart with the new stopwatch program.

Step 10: Test the Stopwatch

Test the completed project:

• Press Button A to start the stopwatch. 
• Observe the timer increasing every second. 
• Press Button B to stop the timer. 
• Press Buttons A+B together to reset the timer back to zero. 

Repeat the experiment several times to verify accurate operation. 

Applications

Sports timing, classroom experiments, robotics, fitness, and science activities.

Advantages

Portable, programmable, reusable, and easy to customize.

Conclusion

The DIY Micro:bit Digital Stopwatch is a simple yet effective STEM project that introduces students to programming, electronics, and digital time measurement through hands-on learning. By creating a stopwatch using the BBC Micro:bit and Microsoft MakeCode, students develop essential coding skills such as variables, loops, timers, and event handling while understanding how software controls hardware. This project encourages creativity, logical thinking, and problem-solving, making it an excellent foundation for exploring more advanced STEM concepts such as robotics, automation, and embedded systems.

 FAQs

1. What is the purpose of the DIY Micro:bit Digital Stopwatch project?

The project helps students learn programming, electronics, and time measurement by creating a functional digital stopwatch using the BBC Micro:bit and Microsoft MakeCode.

2. Which buttons are used to operate the stopwatch?

Button A starts the stopwatch, Button B stops it, and pressing Buttons A+B together resets the timer to zero.

3. Which programming concepts are used in this project?

Students learn variables, loops, event handling, conditional statements, timers, and LED display control through block-based programming.

4. Can this stopwatch be enhanced with additional features?

Yes. You can add features such as lap timing, countdown timers, sound effects, radio communication, data logging, or an external display to make the project more advanced.

5. Where are digital stopwatches commonly used?

Digital stopwatches are widely used in sports, athletics, science laboratories, classrooms, fitness training, robotics competitions, industrial processes, and engineering experiments where accurate time measurement is essential.