MicroCode is a icon-based (text-free), keyboard friendly editor for the micro:bit V2. It is suitable for younger learners and users with variable accessibility needs.

Smiley Buttons MicroCode program

  • Kid-friendly, icon-based, structured web-based code editor
  • Live, the code is downloaded to the micro:bit on every edit
  • Cursor based navigation with keyboard (switch access compatible), mouse, touch, screen reader support
  • Accessories (LEDs, servos, ...) supported via Jacdac

MicroCode is open source at https://github.com/microsoft/microcode.

MicroCode requires micro:bit V2. The micro:bit V1 is **not** supported.


Please be sure the micro:bit is a V2 (Version 2). This project doesn't work with the original / V1 board.

Angled shot of a BBC micro:bit v2.
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Top down view of micro:bit v2 Go Bundle, Batteries and USB Cable.
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Here is a screenshot of one the first examples in MicroCode: smiley buttons.

Smiley Buttons MicroCode program

The goal of this program is to show a smiley and plays a happy sound when pressing A, and a frowney animation and unhappy sound when B is pressed.

The MicroCode language, is defined in terms of pages, where a page has a list of rules, and each rule consists of a When section and a Do section, each with a list of programming tiles. For this example, we have 4 rules.

The first rule tells MicroCode to show an image when 'A' is pressed on the micro:bit.

You will find more samples in the MicroCode documentation.

when button A pressed, show image smiley

  • when press press button A button A, do screen show image smiley.

The next rule tells MicroCode to play a sound when 'A' is pressed as well. All rules run at the same time.

when button A pressed, play happy sound

  • when press press button A button A, do speaker play sound emoji emoji happy happy.

The next two rules are similar but for button 'B'.

The MicroCode web editor is at aka.ms/m9. It requires a browser with WebUSB support.

  • Left, Right, Up, Down moves the cursor
  • the Left and Right keys will wrap around in the editor on the same page
  • the Up key on top of the screen will act as back. It will go back the pages until page 1 is in focus, then pressing up will go back to the start screen.
  • the Down key will wrap around the pages
  • Enter or Space for A button
  • Backspace for B button
  • ] or Page Up to go to the next page, [ or Page Down to go to the previous page
  • Copy the URL to share your program.

Automatic download to micro:bit V2

When the editor does not detect a micro:bit connected to the computer, it will automatically prompt you with instructions on how to connect (requires WebUSB).

Once your micro:bit V2 is paired, the web editor will be able to download your MicroCode program to your micro:bit. This happens on every edit, so your program is always up-to-date (and running)!

If your micro:bit disconnects, you will see a micro:bit icon show up on the upper left corner of the editor. Click on that button to reconnect again.


MicroCode has a lot of accessibility goodness:

  • fully keyboard enabled, and switch panel friendly. Only 3 keys are need to use MicroCode.
  • tooltip read aloud and screen reader support
  • game console support (XBox, ...)

Additional sensors and actuators can be add as Jacdac modules. MicroCode automatically detect additional hardware and will show the additional tiles if supported.

The railroad crossing sample shows a program using a servo and a LED ring Jacdac module.

Railroad crossing MicroCode program

The servo set angle tile servo uses a servo motor move to move an physical arm. The servo set angle tile servo arm orientation is mapped to the wall clock hours: 0 (or 12) is on rotated 90 degree from the resting position to the left, 6 is rotated 90 degree right from the rest position. There is also a secret animation mode when you press the micro:bit logo button.

when press button A, do move servo to 1 o'clock

  • when press press button A button A, do servo set angle servo set arm to 1 o'clock.

The LED LED uses a programmable LED ring module to display blue and red colors.

when press button A, turn LEDs to red

  • when press press button A button A, do LED LED set all color to red red, black and repeat.

This guide was first published on Oct 24, 2022. It was last updated on Oct 24, 2022.