The BBC micro:bit is a computerised project board that’s being given to every year 7 (11-12yr old) kid in the UK. It’s supposed to encourage experimentation and learning to program in the same way that the BBC Micro (and associated BBC programmes) did back in the 80s. I’ve been pretty excited about it since the announcement, though I feared that I’d have to wait until my daughter received hers before I got my hands on one. Luckily a friendly local teacher brought me one to play with, and with a long flight on my hands I decided to have a go at coding Simon (a perennial favourite of mine for trying out new platforms).

There are various different ways to program the micro:bit, but I went with Python (as it’s familiar) and the Mu editor (as plane WiFi isn’t a great way to use online code editors). I used the accelerometer for input, and simple arrows to show the game sequence (up, down, left, right).

Here’s the code, which is also on github (it should work fine in the online Python editor as well as Mu, and yes I know I should probably not be using global variables, but I haven’t refactored much from earlier BASIC and C implementations):

from microbit import *                  # standard Micro:Bit libraries
from array import *                     # to use an array
import random                           # generate random numbers

count = 0                               # initialise counter to 0
wait = 500                              # initialise wait to half a sec
sequence = array('B',[])                # array to hold sequence
display.show("-")                       # start out showing a dash

def squark(dir):                        # function to show arrows
    global wait
    if dir==0:                          # Right
        display.show(Image.ARROW_E)
    elif dir==1:                        # Left
        display.show(Image.ARROW_W)
    elif dir==2:                        # Down
        display.show(Image.ARROW_S)
    elif dir==3:                        # Up
        display.show(Image.ARROW_N)
    else:
        display.show("-")
    sleep(wait)
    display.show("-")
    sleep(wait)

def play_sequence():
    global count                        # use the count global variable
    global sequence                     # use the sequence global variable 
    global wait                         # use the wait global variable
    sequence.append(random.randint(0, 3))       # add a new value to sequence
    for i in range(0, count):           # loop for sequence length
      squark(sequence[i])               # display the arrow
    wait = 500 - (count * 15)           # vary delay to speed things up
    count = count+1                     # increment sequence length
    
def get_tilt():
    x = accelerometer.get_x()           # read left-right tilt
    y = accelerometer.get_y()           # read up-down tilt
    if x > 100:
        return 0                        # Right
    elif x < -100: return 1 # Left elif y > 100:
        return 2                        # Down
    elif y < -100:
        return 3                        # Up
    else:
        return 4                        # Flat
        
def reset_game(): 
   global count
   global sequence
   count=0
   sequence=[]    

def read_sequence():
    global count
    global sequence
    display.show("*")                   # Show that we're waiting
    for i in range(0, count-1):
        while get_tilt()==4:            # Wait for a tilt
            sleep(50)
        input=get_tilt()
        if input == sequence[i]:        # If it's right then show it
            squark(input)
            if i==9:                    # We have a winner
                display.show(Image.SMILE)
                sleep(1000)
                display.show("WINNER")
                reset_game()
        else:
            display.show("X")           # Wrong tilt - game over
            sleep(1000)
            display.show("TRY AGAIN")
            reset_game()
            break
        
while True:
    play_sequence()                     # play the sequence to be remembered
    read_sequence()                     # read the sequence from the player
    sleep(1000)                         # wait a sec