Utility tool that aids in communication and connection of micro:bits.

npm install microbyte

Features

• ✅ - Fully supported
• 🔨 In progress / partially supported
• ❌ Not supported

Protocols

Protocol	Support
Bluetooth	🔨
Radio	❌
USB	🔨

Bluetooth

Service	Support
Connection	✅
Reconnection	🔨 Doesn't retry if failed
Accelerometer	✅
UART - Read	✅
UART - Write	✅
Buttons	🔨 A and B, but not both simultanously
LEDs	🔨 On/Off. No variable strength
PIN IO	🔨 Pins 1,2,3 are addressable
Speaker*	❌

*Not applicable to v1 micro:bits

Radio

Not implemented yet

USB

Feature	Support
Connection	✅
Read Serial number	✅
Read version	✅
Flash .hex file	✅
Friendly name	✅
Serial data	❌

Usage

Bluetooth

This is how you would use the BLE receiver for interacting with the micro:bit

import { MicrobitBluetoothDevice, Microbit } from "microbyte";

const microbit = new Microbit();
const microbitBluetooth = new MicrobitBluetoothDevice();
microbit.setDevice(microbitBluetooth);

// Must be performed as a result of a user input
const connectToDevice = () => {
    microbit.connect();
}

For security reasons, chrome won't allow you to connect the micro:bit unless it's a result of a user action.

<button onClick={connectToDevice}>
    Connect to the microbit
</button>

Once connected, it will attempt to stay connected, if the auto-reconnect feature is enabled

// Attempt to reconnect if disconnected
microbit.setAutoReconnect(true); 

Now in order to get feedback, we must assign a handler.

Microbyte has the interface MicrobitHandler, which is used by the microbit to deliver data such as Accelerometer values

We should implement this interface and assign it to the micro:bit, here's an example.

class MyHandler implements MicrobitHandler {
    public onConnected: (versionNumber?: MBSpecs.MBVersion) => {
        console.log(`A microbit v${versionNumber} has connected`);
    } 

    public onAccelerometerDataReceived: (x: number, y: number, z: number) => {
        console.log(`Accelerometer reads (${x}, ${y}, ${z})`);
    };

    public onButtonAPressed: (state: MBSpecs.ButtonState) => {
        console.log(`Button A changed state to ${state}`);
    };

    public onButtonBPressed: (state: MBSpecs.ButtonState) => {
        console.log(`Button B changed state to ${state}`);
    };

    public onUartMessageReceived: (data: string) => {
        console.log(`Received UART message: ${data}`);
    };

    public onDisconnected: () => {
        console.log('micro:bit was disconnected');
    };

    public onReconnecting: () => {
        console.log('Attempting to reconnect micro:bit');
    };

    public onReconnected: () => {
        console.log('micro:bit was reconnected');
    };

    public onConnectError: (error: Error) => {
        console.log('Microbit failed to connect', error);
    };

    public onReconnectError: (error: Error) => {
        console.log('Microbit failed to reconnect', error);
    };

    public onClosed: () => {
        console.log('Goodbye!');
    };

    public onConnecting: () => {
        console.log("Attempting to connect micro:bit");
    };

    public onClosedError: (error: Error) => {
        console.log("micro:bit failed to close gracefully");
    };
}

Implementing the interface allows us to use it by assigning the handler to the micro:bit.

import { MicrobitBluetoothDevice, Microbit } from "microbyte";

const microbit = new Microbit();
const microbitBluetooth = new MicrobitBluetoothDevice();
microbit.setDevice(microbitBluetooth);

// Create and set the handler
const handler = new MyHandler();
microbit.setHandler(handler)

USB

Using the USB features is done via the USB controller.

import { MicrobitBluetoothDevice, Microbit } from "microbyte";

const microbit = new Microbit();
const usbController: USBController = microbit.getUsbController();

const connectToMicrobitUsb = async () => {
    await usbController.connect();
    const mbName = await usbController.getFriendlyName();
    console.log(`micro:bit name is: ${name}`);
};

Connections must be done as a result of user interaction, just like the bluetooth device.

<button on:click={connectToMicrobitUsb}>Connect USB</button>

Using the micro:bit USBController, you can read the model number and flash .hex files.

import { MicrobitBluetoothDevice, Microbit } from "microbyte";

const microbit = new Microbit();
const usbController: USBController = microbit.getUsbController();

const flashHex = async () => {
    let hex = "v1.hex";
    // We use different hex files depending on the micro:bit model
    if (usbController.getModelNumber() === 2) {
        hex = "v2.hex"; // Can be any URL. These files are located on /v2.hex
    }

    // Use fetch to retrieve the data from a URL and convert it to an ArrayBuffer
    const hexFile: Response = await fetch(hex);
    const buffer: ArrayBuffer = await hexFile.arrayBuffer();
    usbController.flashHex(buffer, (prog) => {
        console.log(`Flashing progress: ${prog * 100}%`)
    });
};

Then we can flash hex files by clicking a single button.

<button on:click={flashHex}>Flash hex file</button>

Examples

Examples can be found in /examples/

For devs

npm run dev

Continously compile project during development

npm build

Builds the project

npm run docs

Produces documentation (Not used at the moment)

Notice

This project is developed in collaboration with Aarhus University in Denmark for the ML-Machine project.

License: MIT