microbit / Meteors!

Intermediate level microbit - 1hr

Original game & code by Emily & Claire!

In Meteors! we create a game that you control using the A & B buttons moving your spaceship to avoid meteors coming towards you.

You will need…

• A BBC microbit

Step Zero: Open up the block editor

Open up the Microbit PXT editor and then plug into your microbit into your computer.

Step One: Controlling the player LED

We will use the A & B buttons to move left and right. To keep track of where the user is, we need to use a variable: make a new one called player.

Now, use this code to move the player LED left and right.

Upload the code to the microbit. What happens when you click A when the LED is all the way to the left?

Step Two: Fix the player controls

The LED for the player disappear off left and right when you go too far!

The LEDs on the microbit have values that they correspond to, you can see them here…

You can the player dropping off the edges by stopping the player variable from getting too big (more than 4 going right) or too small (less than 0 going left).

We also want to start with the player in the middle, so we can do this by pressing both A+B buttons at the same time which will reset and start the game.

Upload the code to the microbit. Test that the player LED doesn’t fall off the edges!

Step Three: Falling meteors

Now we’ve got the player working, we can move onto the meteors.

These start at a random position on the top row of the grid and gradually fall down. So we need two variables to control their position, meteor-x and meteor-y.

meteor-x is set to a random value between 0 and 4, and meteor-y is controlled by a for loop which sets meteor-y from 0 to 4 in stages.

Add this code to the current A+B button press event…

When the meteor reaches the bottom row, we need to see if the meteor has hit the player. We do this by comparing the meteor-x and player variables. If they are the same, then the meteor has hit the player :(

Almost done! We now want to make sure that we keep playing the game until a meteor hits the player. We can do this using a alive variable and a while loop

Finally… change the player controls so that the player can’t move if the game is over:

Upload the code to the microbit. Play the game!

Challenge I: Keep a score (beginners, 5 mins)

• Add a score variable and add 1 to it every time a meteor is avoided.
• Show this variable instead of the giant X at the end of the game.

Challenge II: Make the game harder as your score increases (intermediate, 15 mins)

• Now you’ve hot a score variable, use it to change how long the delay is in the meteor dropping code.
• The meteor shower starts slow and gets quicker as the score variable increases.

Full code

Full code including the challenges is seen here

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This microbit worksheet 'Meteors!' from CoderDojo York is licensed under a
Creative Commons Attribution-NonCommercial 4.0 International License.
No commercial use of our material is permitted