Simple Python game with micro:bit OLED display

I’ve managed to get a simple game working on my micro:bit OLED display, and I ditched the breadboard at the same time, meaning that it should be possible to build this into a small case. I may even add some external buttons and perhaps some sound?

Here’s what I used:

I added the extra Python modules using the new micro:bit Python editor’s feature to add extra files to your projects. It supports WebUSB, so using a recent version of Chrome you can flash Python projects straight onto your micro:bit without having to drag and drop HEX files.

Connecting the OLED is easy, especially if you have the well-labelled pin:bit – connect micro:bit 3v to VCC on the display, GND to GND, micro:bit pin 19 SCL (serial clock) to the display’s SCL pin and micro:bit pin 20 (SDA / serial data) to the SDA pin on the display.

The program works by creating ‘stamps’ – like crude sprites – for 3 hazards (a duck, a ghost and a tortoise), all using graphics from the micro:bit’s own built-in 5×5 icons. This is a neat touch that avoids having to create your own bitmap graphics.

You move left and right using A and B buttons, and press A+B together to move forward – you can’t move backwards! When you reach the top you level up, complete 10 levels to win.

There was no function I could find in the Python modules to invert the screen, which is possible if you know what control codes to send, so I added the flash() function which will flash the screen any number of times by making the screen negative then positive quickly in succession. I use this effect when you level up, win or lose.

The levels don’t get harder – it’s running as fast as it can, so I can’t speed it up. To make it more challenging I might add more hazards or slow the player down in some way. Adding sound would also be a logical next step, along with building into a small case, perhaps with some external buttons.

My main Python game program is here, and you can download the whole project HEX file here.

from ssd1306 import initialize, clear_oled, command
from ssd1306_stamp import draw_stamp
from ssd1306_img import create_stamp
from ssd1306_text import add_text
from microbit import sleep, display as LED, Image, button_a as A, button_b as B

def flash(times):
    for i in range(times):
        command([0xa7])
        sleep(300)
        command([0xa6])
        sleep(300)

def move_stamp(x1, y1, x2, y2, stmp):
  draw_stamp(x1, y1, stmp, 0, 0)
  draw_stamp(x2, y2, stmp, 1, 1)

alive = True
level = 0
ghostx, ghosty = 3, 10
ghostDirection = 1
tortoiseX, tortoiseY = 40, 20
tortoiseDirection = -1
duckX, duckY = 20, 5
duckDirection = 1
playerX, playerY = 32, 27

LED.show(level)
initialize()
clear_oled()
ghost = create_stamp(Image.GHOST)
tortoise = create_stamp(Image.TORTOISE)
duck = create_stamp(Image.DUCK)
player = create_stamp(Image.TRIANGLE)
draw_stamp(ghostx, ghosty, ghost, 1)
draw_stamp(tortoiseX, tortoiseY, tortoise, 1)
draw_stamp(duckX, duckY, duck, 1)
draw_stamp(playerX, playerY, player, 1)

while alive:
    oldGhostX = ghostx
    ghostx += ghostDirection
    if ghostx > 58:
        ghostDirection = -1
    if ghostx < 3:
        ghostDirection = 1
    move_stamp(oldGhostX, ghosty, ghostx, ghosty, ghost)

    oldTortoiseX = tortoiseX
    tortoiseX += tortoiseDirection
    if tortoiseX > 58:
        tortoiseDirection = -1
    if tortoiseX < 3:
        tortoiseDirection = 1
    move_stamp(oldTortoiseX, tortoiseY, tortoiseX, tortoiseY, tortoise)

    oldDuckX = duckX
    duckX += duckDirection
    if duckX > 58:
        duckDirection = -1
    if duckX < 3:
        duckDirection = 1
    move_stamp(oldDuckX, duckY, duckX, duckY, duck)

    oldPlayerX = playerX
    playerX = playerX - 1 if (A.is_pressed() and playerX > 0) else playerX
    playerX = playerX + 1 if (B.is_pressed() and playerX < 58) else playerX
    oldPlayerY = playerY
    playerY = playerY - 1 if (A.is_pressed() and B.is_pressed() and playerY > 0) else playerY

    if oldPlayerX != playerX or oldPlayerY != playerY:
        move_stamp(oldPlayerX, oldPlayerY, playerX, playerY, player)

# have we reached the top?
    if playerY == 1:
        level = level + 1
        LED.show(level)
        flash(1)
        draw_stamp(playerX, playerY, player, 0)
        playerX, playerY = 32, 27
        draw_stamp(playerX, playerY, player, 1)

# have we won?
    if level == 10:
        alive = False

# have we hit anything?
    if ghostx-3 <= playerX <= ghostx+3 and ghosty-3 <= playerY <= ghosty+3 \
    or tortoiseX-3 <= playerX <= tortoiseX+3 and tortoiseY-3 <= playerY <= tortoiseY+3 \
    or duckX-3 <= playerX <= duckX+3 and duckY-3 <= playerY <= duckY+3:
        alive = False

if level == 10:
    LED.show(Image.HAPPY)
    clear_oled()
    add_text(3, 1, 'You win!')
    flash(5)
else:
    LED.show(Image.SKULL)
    clear_oled()
    add_text(2, 1, 'Game over!')
    flash(5)
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2 Responses to Simple Python game with micro:bit OLED display

  1. Christy Cairns says:

    Hi, I followed your tutorial and got the game to work. I tried to make it more complicated by making the ghost move faster.

    The result was a trailing ghost :
    https://www.youtube.com/watch?v=T3bnkqbmJaM&feature=emb_title#

    http://blogs.brighton.ac.uk/ccdigifab/2020/03/15/embedded-programming-mircobit-oled-game/

    Is this what you were referring to when you mention “it’s running as fast as it can”?

    Thanks – Christy

    • blogmywiki says:

      Hi Christy – that’s awesome! I don’t know why your ghost is, er, ghosting, but I am going to have a play with your code. It would be cool if we could create some more little micro:bit games for OLED displays, they’re relatively inexpensive and very easy to connect if you have a breakout board.
      best wishes
      Giles

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