Tales of
Web Bluetooth
@sandropaganotti
Device
Service
Characteristic
navigator.bluetooth.requestDevice({
filters: [{
services: [TOGGLE_LIGHT],
}]
})
.then(device =>
device.gatt.connect())
.then(server =>
server.getPrimaryService(TOGGLE_LIGHT))
.then(service =>
service.getCharacteristic(TOGGLE_LIGHT_CH))
.then(characteristic =>
characteristic.readValue()
.then(value =>
console.log((new DataView(value)).getUint8(0)
? 'On'
: 'Off'
)
);
Annoyances
- not a standard (yet)
- no discovery (yet)
- only passive
- connection only as a result of a direct user action
- handling dropped connections
- writing while another write is in process
- connecting while another connection is in process
- only some services / characteristics are standard
// using JSGatt
var awox = new window.GATT.Device();
var toggle = awox.register(
SET_LIGHT_SERVICE,
SET_LIGHT_CHARACTERISTIC
);
button.addEventListener(function(){
// turn the light on
toggle(new Uint8Array(1));
});
WebBluetooth + WebRTC =
Camera Color Picker
Camera
Dominant Color
Video
Canvas
Pixels
Bluetooth
// register color service
var awos = new window.GATT.Device();
var color = awos.register(...);
// stream camera to a <video> element
window.navigator
.mediaDevices
.getUserMedia({audio: false, video: true})
.then(function(stream) {
video.srcObject = stream;
});
// draw a <video> frame on a <canvas> 2d context
context.drawImage(video, 0, 0);
var pixels = context.getImageData(...).data;
// get the dominant color using lokesh/color-thief
var dominant = MMCQ.quantize(pixels, 2).palette()[0];
// send the color to the lamp
color(new Uint8Array(dominant));
WebBluetooth + WebSpeech =
Alexa
webSpeechRecognition
"on"-"off"
Bluetooth
// register toggle service
var awos = new window.GATT.Device();
var toggle = awos.register(...);
// start recognition on button's click
var recognition = new window.webkitSpeechRecognition();
recognition.continuous = true;
button.addEventListener('click', function() {
toggle(new Uint8Array([1])).then(function() {
recognition.start();
});
});
// process the recognized text
recognition.addEventListener('result', function(e) {
var text = e.results[e.resultIndex][0].transcript;
if (/off/.test(text)) {
toggle(new Uint8Array([0]));
} //...
});
Print Battery Status Using
Notifications
characteristicvaluechanged
// get characteristic using the standard flow
characteristic.startNotifications().then(_ => {
characteristic.addEventListener(
'characteristicvaluechanged',
handleNewValue // function
);
});
// to stop
characteristic.stopNotifications().then(_ => {
characteristic.removeEventListener(
'characteristicvaluechanged',
handleNewValue // function
);
});
// this time service and characteristic are known
var phone = new window.GATT.Device();
var battery = phone.register(
'battery_service', 'battery_level'
);
// subscribe to the event
button.addEventListener('click', function() {
battery.getCharacteristic().then(function(ch) {
ch.startNotifications().then(function(){
ch.addEventListener(
'characteristicvaluechanged', printValue
);
});
});
});
// update the progress bar
function printValue(event) {
updateProgessBar(event.target.value.getUint8(0));
}
Bonus Round
Demo 2
Drone
kudos:
poshaughnessy/web-bluetooth-parrot-drone voodootikigod/node-rolling-spider
function directions() {
move(new Uint8Array(MOVE_SEQUENCE(
0,
key.isPressed('W') ? 20 : (key.isPressed('S') ? -20 : 0),
key.isPressed('D') ? 20 : (key.isPressed('A') ? -20 : 0),
0
))).then(function() {
if(!isLanding) {
setTimeout(directions, 50);
}
});
}
takeoff.addEventListener('click', function() {
performAuthenticationAndTakeOff()
.then(function() {
setTimeout(directions, 50);
});
});
land.addEventListener('click', function() {
isLanding = true;
handshake(new Uint8Array(LAND_SEQUENCE()));
});
Moar IoT
WebUSB
WebUSB supporting device
Chrome notification
pointing to a page in the device's manifest
navigator.usb.getDevices().then(devices => {
devices.map(device => {
console.log(device.productName);
console.log(device.manufacturerName);
});
})
Thanks!
images from Flickr, credits to:
@pimthida, @qiaomeng, @lolwho, @!steevithak, @tylerlove, @peaches
Tales Of Web Bluetooth
By sandropaganotti
Tales Of Web Bluetooth
Slides for JSDay 2016
- 2,657