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/*
* This code is written with a lot of help from these resources:
* https://github.com/antefact/microBit.js/blob/master/src/microBit.js
* https://gist.github.com/kotobuki/7c67f8b9361e08930da1a5cfcfb0653f
* https://lancaster-university.github.io/microbit-docs/resources/bluetooth/bluetooth_profile.html
*/
const UART_SERVICE_UUID = "6e400001-b5a3-f393-e0a9-e50e24dcca9e";
/* Used for reading UART data from micro bit */
const UART_TX_CHARACTERISTIC_UUID = "6e400002-b5a3-f393-e0a9-e50e24dcca9e";
/* Used for writing UART data to micro bit */
const UART_RX_CHARACTERISTIC_UUID = "6e400003-b5a3-f393-e0a9-e50e24dcca9e";
/* The event service characteristic (which extends the uBit message bus over bluetooth) */
const EVENT_SERVICE_CHARACTERISTIC_UUID = "e95d93af-251d-470a-a062-fa1922dfa9a8";
/* This should be read once connected, as the ubit will advertise which events it wants to subscribe to */
const UBIT_REQUIREMENT_CHARACTERISTIC_UUID = "e95db84c-251d-470a-a062-fa1922dfa9a8";
/* The characteristic where we should write the events we wish to be informed of from the microbit */
const CLIENTREQUIREMENTS_CHARACTERISTIC_UUID = "e95d23c4-251d-470a-a062-fa1922dfa9a8"
/* The characteristic used for reading EventService messages */
const UBITEVENT_CHARACTERISTIC_UUID = "e95d9775-251d-470a-a062-fa1922dfa9a8";
/* The characteristic used for writing EventService messages */
const CLIENTEVENT_CHARACTERISTIC_UUID = "e95d5404-251d-470a-a062-fa1922dfa9a8";
/* This table is retrieved from this site:
* https://github.com/lancaster-university/microbit-dal/blob/master/inc/bluetooth/MESEvents.h */
export const MESEvents = {
MES_DPAD_CONTROLLER_ID: 1104,
MES_DPAD_BUTTON_A_DOWN: 1,
MES_DPAD_BUTTON_A_UP: 2,
MES_DPAD_BUTTON_B_DOWN: 3,
MES_DPAD_BUTTON_B_UP: 4,
MES_DPAD_BUTTON_C_DOWN: 5,
MES_DPAD_BUTTON_C_UP: 6,
MES_DPAD_BUTTON_D_DOWN: 7,
MES_DPAD_BUTTON_D_UP: 8,
MES_DPAD_BUTTON_1_DOWN: 9,
MES_DPAD_BUTTON_1_UP: 10,
MES_DPAD_BUTTON_2_DOWN: 11,
MES_DPAD_BUTTON_2_UP: 12,
MES_DPAD_BUTTON_3_DOWN: 13,
MES_DPAD_BUTTON_3_UP: 14,
MES_DPAD_BUTTON_4_DOWN: 15,
MES_DPAD_BUTTON_4_UP: 16
}
class BluetoothService {
SERVICE_UUID = null;
}
class EventService extends BluetoothService {
static SERVICE_UUID = EVENT_SERVICE_CHARACTERISTIC_UUID;
service;
constructor(service, ubitEvent) {
super();
this.service = service;
this.ubitEvent = ubitEvent;
console.log("EventService initialized.");
}
sendEvent(event_type, event_value) {
this.ubitEvent.writeValue(
new Uint16Array([event_type, event_value])
);
}
static async getService(gattServer) {
console.debug("Getting EventService");
let service = await gattServer.getPrimaryService(EventService.SERVICE_UUID);
console.debug("Getting UBitevent characteristic");
let ubitEventCharacteristic = await service.getCharacteristic(CLIENTEVENT_CHARACTERISTIC_UUID);
return new EventService(service, ubitEventCharacteristic);
}
}
export class uBitBLE {
eventService;
device;
constructor() {
this.onConnectCallback = function() {};
this.onDisconnectCallback = function() {};
}
onConnect(callbackFunction) {
this.onConnectCallback = callbackFunction;
}
onDisconnect(callbackFunction) {
this.onDisconnectCallback = callbackFunction;
}
isConnected() {
if (this.device) {
return this.device.gatt.connected;
} else {
return false;
}
}
disconnect() {
if (this.isConnected()) {
this.device.gatt.disconnect();
}
}
async searchDevice() {
this.device = await navigator.bluetooth.requestDevice({
filters: [{namePrefix: "BBC micro:bit"}],
optionalServices: [EVENT_SERVICE_CHARACTERISTIC_UUID]
});
this.device.addEventListener('gattserverdisconnected', this.onDisconnectCallback);
console.log("Connected to new device", this.device.name, this.device.id);
console.debug("Connection to GATT server...");
const server = await this.device.gatt.connect()
this.onConnectCallback();
console.debug("Getting services...");
const eventService = await EventService.getService(server);
this.eventService = eventService;
}
}
function getSupportedProperties(characteristic) {
let supportedProperties = [];
for (const p in characteristic.properties) {
if (characteristic.properties[p] === true) {
supportedProperties.push(p.toUpperCase());
}
}
return '[' + supportedProperties.join(', ') + ']';
}
function eventByteArrayToString(event) {
let receivedData = [];
for (var i = 0; i < event.target.value.byteLength; i++) {
receivedData[i] = event.target.value.getUint8(i);
}
return String.fromCharCode.apply(null, receivedData);
}
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