Stopwatch

Introduction

This project turns the micro:bit into a simple stopwatch. Pressing A starts the timer. Pressing B displays the elapsed seconds.

Step 1

Add an event to run code when ||input:button A is pressed||.

input.onButtonPressed(Button.A, function () {
})

Step 2

Add code inside the ||input:button A is pressed|| event to store the current ||input:running time|| in a variable ||variables:start||. This is the start time.

let start = 0
input.onButtonPressed(Button.A, function () {
    start = input.runningTime()
})

Step 3

Add another event to run code when ||input:button B is pressed||.

input.onButtonPressed(Button.B, function () {
})

Step 4

Add code in that event to compute the difference between the ||input:running time|| and ||variables:value|| time. This is the elapsed number of milliseconds since pressing button A.

let start = 0
input.onButtonPressed(Button.B, function () {
    let elapsed = input.runningTime() - start
})

Step 5

After setting the ||variables:elapsed|| time, add code to ||basic:show|| the number of milliseconds ||variables:elapsed||. Use ||Math:integer division|| to divide ||variables:elapsed|| by 1000 and get seconds.

let start = 0
input.onButtonPressed(Button.B, function () {
    let elapsed = input.runningTime() - start
    basic.showNumber(Math.idiv(elapsed, 1000))
})

Step 6

Try your program in the simulator. Press A to start the stopwatch and press B to get the current elapsed time. You can press B multiple times.

Step 7

If you have a micro:bit connected, click |Download| to transfer your code!