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Add delay after connecting to BLE device and start notifications before adding on characteristic change event listener

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Peter Stockings
2023-01-26 12:40:38 +11:00
parent f8c422db8d
commit 8c49dea474
1 changed files with 13 additions and 5 deletions
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18
static/js/BLE.js
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@@ -1,3 +1,7 @@
function delay(ms) {
return new Promise((resolve) => setTimeout(resolve, ms));
}
async function connect(props) { async function connect(props) {
const device = await navigator.bluetooth.requestDevice({ const device = await navigator.bluetooth.requestDevice({
filters: [{ services: ["cycling_speed_and_cadence"] }], filters: [{ services: ["cycling_speed_and_cadence"] }],
@@ -5,15 +9,19 @@ async function connect(props) {
}); });
console.log(`%c\n👩🏼‍⚕️`, "font-size: 82px;", "Starting CSC...\n\n"); console.log(`%c\n👩🏼‍⚕️`, "font-size: 82px;", "Starting CSC...\n\n");
const server = await device.gatt.connect(); const server = await device.gatt.connect();
await delay(500);
console.log("Getting Service...");
const service = await server.getPrimaryService("cycling_speed_and_cadence"); const service = await server.getPrimaryService("cycling_speed_and_cadence");
const char = await service.getCharacteristic("csc_measurement"); console.log("Getting Characteristic...");
char.oncharacteristicvaluechanged = props.onChange; const characteristic = await service.getCharacteristic("csc_measurement");
char.startNotifications(); await characteristic.startNotifications();
return char; console.log("> Notifications started");
characteristic.addEventListener("characteristicvaluechanged", props.onChange);
} }
function parseCSC(e) { function parseCSC(e) {
const flags = e.target.value.getUint8(0, true); const value = e.target.value;
const flags = value.getUint8(0, true);
const hasWheel = !!(flags & 0x01); const hasWheel = !!(flags & 0x01);
const hasCrank = !!(flags & 0x02); const hasCrank = !!(flags & 0x02);
let index = 1; let index = 1;