BUILD BEYOND THE KEYBOARD

Makey Makey & micro:bit

The real Scratch extensions are included in Mabni. Choose Add Extension at the bottom of Scratch’s block categories, then select the hardware card.

Open Scratch →

Makey Makey

Connect the board by USB. It behaves like a keyboard. No network, Bluetooth or Scratch Link is needed. Add the Makey Makey extension, keep the Scratch stage focused, and try “when space key pressed”.

Build a cardboard controller, a piano or an accessible button. Follow the board maker’s instructions for its Earth connection and suitable conductive materials.

micro:bit

Copy the included Scratch firmware to the MICROBIT drive. Turn on Bluetooth, open Mabni in Chrome or Edge at localhost or trusted HTTPS, then add the micro:bit extension. Choose the board in the browser’s Bluetooth picker. The direct Web Bluetooth connection is completely local and needs no native helper.

Download bundled Scratch firmware →

Scratch uses the board as a controller for a project running on the computer. It does not export a standalone Scratch program to the board.

Prepare the lab once

Test Chrome/Edge Bluetooth support and the included Scratch firmware before taking the lab offline. For hardware on a student PC, use a local Mabni copy at localhost or a trusted HTTPS classroom server. Makey Makey works through normal keyboard input over the classroom LAN.

The normal Chrome/Edge path uses no network connection at all. An advanced local-only Scratch Link 2 socket is also included for labs that already have that compatible helper. The current Windows direct installer is the older 1.4.3 version; do not assume it provides the Link 2 offline transport. Mabni never falls back to the online DNS/certificate connection.

Connection troubleshooting

Check the computer’s Bluetooth supports BLE and is enabled.
Use Chrome or Edge with Web Bluetooth enabled. Open the micro:bit card or its Connect button, then choose the board in the browser. Cancelling the chooser does not connect a board.
Flash the bundled Scratch HEX; different MakeCode firmware will not speak the Scratch protocol.
Use the board name shown on its LED display. If reconnecting after re-flashing, remove a stale operating-system pairing and try again.
Browser Bluetooth requires a secure context. Open a local Mabni copy at http://localhost:8000/scratch/ on the board’s computer, or use a properly secured HTTPS classroom server. A plain LAN HTTP link can still run Scratch and Makey Makey, but micro:bit Bluetooth access may be blocked by the browser.
Allow Bluetooth access only to the micro:bit you select. The board connects to the child’s own computer, not the teacher’s PC. If using the optional Link 2 socket, local-helper permissions can also apply.

The editor and blocks work fully offline. Physical Bluetooth communication requires a compatible board, adapter and supporting browser. The direct path needs no helper installation. Those physical connections still need a classroom hardware test.

Official preparation references, for a teacher while online: Scratch micro:bit setup · Makey Makey setup · Scratch Link 2 requirements · Offline loopback architecture · Current Chrome local-helper permissions.