ghoelzl / microbit_nanochess

Toledo Nanochess on the BBC micro:bit

Toledo Nanochess on the BBC micro:bit

Introduction

Some years ago I had the idea of implementing a chess program on the BBC micro:bit (https://microbit.org) since this little device has already a built-in 5x5 LED matrix and two buttons for user inputs. After some research I found the wonderful implementation of Oscar Toledo's Nanochess (https://nanochess.org/chess3.html). I was completely fascinated of this little program. The time has come and I ported this awesome chess program. This is probably now one of the smallest chess computers in the world.

I used https://nanochess.org/toledo_nanochess.c as a starting point and Arduino IDE 2.0.3 (see https://www.arduino.cc/en/software) with the installed "Adafruit MicroBit library" (see https://github.com/adafruit/Adafruit_Microbit).

Arduino IDE has some problems with the tricky preprocessor defines, so I sent the file through gcc with the -E option. After playing around with the tiny program and redirecting the Standard-I/O to the serial interface I decided to write a simple user interface for being completely independent.

Demo

You can find a demo of the program at https://www.youtube.com/watch?v=Vc_DAjjW53I.

Upload to the BBC micro:bit

The "one minute solution" for uploading the executable binary to the micro:bit is to drag and drop the file microbit-nanochess.hex to the micro:bit. The hex file was retrieved with the uBitTool from https://github.com/carlosperate/ubittool/releases. Since I don't own a micro:bit v2 I can't promise whether this method works there. If you want to do further development you have to install the Arduino IDE (https://www.arduino.cc/en/software) and micro:bit libraries from adafruit, documented at https://learn.adafruit.com/use-micro-bit-with-arduino. Just open the microbit_nanochess.inofile and push the Upload Button.

Usage

After starting, the user is welcomed with Nanochess followed by the color whose turn it is. A > appears, which means that you can skip the move input and let the micro:bit calculate the move.

With the A-button you can select the desired letter or number whereas with the B-button you will confirm your selection.

After entering your first move (eg. C2C4) a >appears again, which should be confirmed. Selecting a letter in this step (either N, Q, Ror B) is just for the case of a promotion indicating the desired figure.

Now the micro:bit confirms the move and repeats the procedure with the other color. So it's quite easy to switch to the other color.

Credits

• To Oscar Toledo (https://nanochess.org/author.html) for his awesome little chess program and for his detailed book at https://nanochess.org/chess3.html#book.
• To adafruit (https://www.adafruit.com) for the well documented micro:bit library.
• To BBC R&D (https://www.bbc.co.uk/rd) and other companies for developing this nice little device.