Minecraft Game Controller

Challenge

We’ve seen how awesome the microbit is and how to run python scripts on the pi to control Minecraft. What about if we could connect the two together and have the microbit send commands to Minecraft?

Printing

All the examples we have seen so far have been putting information on the microbit’s “screen” (the 5x5 LED matrix). We have to use display.show() or display.scroll() to show text. In some of the earlier examples on the laptops, we used python’s print function. Could we use the print function on the microbit? Where would the text go?

The print function is actually wired up to the USB serial port so


print('hello world')

…is sent to whatever is connected to the other end of the USB cable (if it can read it).

Microbit

On the microbit we can write some code to check position of the accelerometer and if any buttons have been pressed. Then we can use the print function to send that data to the USB port.


from microbit import *

def write_sensor_data():
    x, y, z = accelerometer.get_x(), accelerometer.get_y(), accelerometer.get_z()
    a, b = button_a.was_pressed(), button_b.was_pressed()
    print(x, y, z, a, b)

while True:
    sleep(100)
    write_sensor_data()

Communication

To get the Pi and the microbit to talk together they both need to share the same settings and know about each other. When we plug them together with a USB cable, the Pi will assign a name to the microbit that might not be obvious (it doesn’t really know it’s a microbit). We need to do some investigation to work out what the Pi calls the microbit when it’s plugged in.

Raspberry Pi

First, you will need to install pySerial using:


sudo apt-get install python-serial

or by downloading from here. With nothing connected to the Pi, open a terminal window and run this command:


ls /dev/ttyA

and make a note of all the results (if any). Next connect the microbit to the Pi by the USB cable and run the command again and look for something like dev/ttyACM1:


ls /dev/ttyA*

dev/ttyACM1

or run the command:


dmesg

171769.685287] cdc_acm 1-1.2:1.1: ttyACM0: USB ACM device

Once we know what these details we can change the code to make sure we are using the right name. We need to write code to run on both sides - the Pi and the microbit - to communicate correctly.

Example Solution

Pi

On the raspberry pi, this is the code that will read the data from the USB port and decode it.


import serial

# *** THE NEXT LINE MIGHT NEED TO BE CHANGED ***
PORT = "/dev/ttyACM1"
# *** 
BAUD = 115200

s = serial.Serial(PORT)
s.baudrate = BAUD
s.parity   = serial.PARITY_NONE
s.databits = serial.EIGHTBITS
s.stopbits = serial.STOPBITS_ONE

while True:
  data = s.readline().decode('UTF-8')
  data_list = data.rstrip().split(' ')
  
  try:
    x, y, z, a, b = data_list

    # print out the values ?
    # do something with these values
    # use x, y, z to move the player?
	# if x > 0: move player right
	# if x < 0: move player left
	# world.player.setPos(x, y, z) ?
  except:
    pass

s.close()

Extensions