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title Reaction Timer
layout text-width-sidebar
meta-description microbit game in python to time the reaction speed of a user pressing a button.
simple-description Reaction Timer
share true
comments true
author romilly
strapline Reaction Timer Game
aboutbox A single person game to time the reaction speed of a user's input.
cats medium
date 2017-02-02 10:20:00 UTC
date-updated 2017-02-02 10:20:00 UTC

{% highlight python %}{% include_relative code/reaction-timer.py %}{% endhighlight %}

This is a simple game to show how long it takes a user to press a button.

  • Show an animation of a clock face for a random amount of time
  • Prompt user to press a button
  • Display time taken for the user to press the button

A video will go here.

Code Explained

{: .ui .dividing .header}

Import Random

{% highlight python %} from microbit import * import random {% endhighlight %}

The program uses random.randint(500, 5000) to return a random number between 500 and 5000. The random number module must be imported with import random.

The random number between 500 and 5000 is used to tell the microbit to sleep for a random amount of time between .5 and 5 seconds.

Clock Animation

A clock animation is shown on the microbit before prompting the user to press a button. The code is:

{% highlight python %} display.show(Image.ALL_CLOCKS, loop=True, wait=False, delay=100) {% endhighlight %}

Image.ALL_CLOCKS is a list of all the clock images, eg CLOCK1, CLOCK2, CLOCK3, etc.

The microbit micropython documentation gives a complete explaination of display.show:

In this program, loop=True causes all images in the Image.ALL_CLOCKS list to repeat. wait=False causes the animation to happen the the background.

Calculate Reaction Time

  • running_time() returns the amount of time the microbit has been running in milliseconds since the last reset.
  • start_time is the time at which the timer began waiting for a user to press button_b.
  • end_time is the time at which the user pressed button_b.

The difference between start_time and end_time is the time in milliseconds it took for the user to press button_b.

Wait for User to Press Button

{% highlight python %} while not button_b.was_pressed(): sleep(20) {% endhighlight %}

button_b.was_pressed() returns true if button_b was pressed since the last time it was called.

This while loop continues while button_b was not pressed. It essentially waits for button_b to be pressed.

Scroll Reaction Time

{% highlight python %} display.scroll(str(reaction_time)) {% endhighlight %}

Convert reaction_time (the time taken for the user to press the button) to a string and scroll it on the display.

Reset

{% highlight python %} display.show(Image.ARROW_W) while not button_a.was_pressed(): sleep(20) reset() {% endhighlight %}

At the end of the program, an arrow points at button_a. A while loop waits for the user to press button_a.

When button_a.was_pressed(), reset() is called which restarts the microbit and causes the program to run again.

Next Steps

  • It's possible to cheat but pressing button_b when the clock animation is showing. Introduce a way of stopping the cheating.
  • Make a two player game.

See More