Door cracker

The door cracker demonstrates how to transmit binary data over 2 wires between different MakeCode devices (MakeCode Arcade to BBC micro:bit in this instance). This is a simplified variant of the method that only transmits the values 0, 1, 2 and 3. A more comprehensive implementation that transmits all 16 hexadecimal codes 0 to F is also available but requires a bit more coding so was not used in this example.

This is a moderately complicated part of the escape room.

Key details

Menu Button - mixes up the numbers.
Direction Buttons - slides the sprites into the empty slot.
A Button - transmits the code over the wires.
B button - displays the code that will be sent over the wires.

Bill of materials

MakeCode Arcade with Edge Connector.
2 crocodile clips.

NOTE: This MakeCode Arcade project will ONLY work with a MakeCode Arcade device that has an edge connector. If you try and load it on a device without an edge connector, the application wont start.

Click here for the completed code (MakeCode).

Here is an example of the door cracker running on a Meowbit (code for Meowbit).

example

Here is an example of the door cracker running on a Kitronic Arcade shield for BBC micro:bit (code for BBC micro:bit).

example

Explanation

There are two parts to this project:

A slider puzzle
Transmission of the digits from the slider puzzle to another device.

For details of how data is transmitted over a wire between two devices, see the explanation on the door lock which receives the data here.

The slider is a relatively simple MakeCode Arcade game. There are 15 sprites, each of which has one of 4 images that represent the numbers zero, one, two or three. There are four new sprite kinds, also called zero, one, two and three. The sprites are tracked using an array. The screen has space for 16 sprites spread out across the screen. As there are only 15 sprites, there is always a gap. Using the direction buttons, the player can slide a sprite that is adjacent to the gap into it. This allows the sprites to be moved around.

As the sprites move, the array is kept updated to keep the order of the sprites known. This information is then used when the player presses the either the A or B buttons. The B button displays on the screen the digits that are to be transmitted. The A button is used to transmit those digits over the wire.

screen shot