Fun with Bluetooth

A presentation at Food ‘n Code in September 2019 in Amsterdam, Netherlands by Niels Leenheer

classic bluetooth vs. m o r a t a a w a h n e h d t e r o o e d bluet n e e r e d ie bedien dro n es en ande bluetooth low energy re coole sh i t

bluetooth low energy ook bekend als B l Bluetooth Smar t uetooth LE B l u e t o o t h 4 BLE

bluetooth low energy ook bekend als B l Bluetooth Smar t uetooth LE B l u e t o o t h 4 and 5 BLE

10 miljoen apparaten met bluetooth worden elke dag gemaakt

r e t e m e s o c glu iem d n a h s d an

u b y a pl s lb e r e h p b l u b y a l p

generic attribute profile m o , t gat n i l a p a g dat s a w k i u r geb

§ i device information light e s e r e d r e e m t a a r a p p a r e p s rvice

i device information battery flight control

i device information battery steering control

i device information manufacturer model number serial number hardware revision firmware revision software revision … s c i t s i r e t c a r a h c e r e e c i d v r r e s r mee e p

server service characteristic value array of objects object property value

services en characteristics hebben altijd een uuid 16 bit of 12 8 bit

i device information 16 bit 128 bit 0x180A 0000180A-0000-1000-8000-00805F9B34FB

battery 16 bit 128 bit 0x180F 0000180F-0000-1000-8000-00805F9B34FB

steering control light maar iede flight c reen doet h 16 bit 128 bit et toch wordt afgeraden elke UUID behalve de reeks xxxxxxxx-0000-1000-8000-00805F9B34FB

i device information manufacturer model number serial number hardware revision firmware revision software revision …

i 0x180A 0x2A29 0x2A24 0x2A25 0x2A27 0x2A26 0x2A28 … s l e c goed vo ht voor de or het b duidelij esparen kheid, van dat a

d n u e t s r e d n o c i t e s i z r e e d t c n a r a a v le ke ch een of meer lezen schrijven schrijven zonder bevestiging notificatie

elke waarde is een array van bytes p y t a t a n e ge d e r e g o h e e l l a es, s e t y b n

n e t i e f e i a a s r e v o fun with bluetooth

web bluetooth nog steed s niet het leuke ged eelte :-( api

navigator.bluetooth.requestDevice({ filters: [ { namePrefix: ‘PLAYBULB’ } ], optionalServices: [ 0xff0f ] }) .then(device => device.gatt.connect()) .then(server => server.getPrimaryService(0xff0f)) .then(service => service.getCharacteristic(0xfffc)) t a w r e s w o r b e d n e l l e we ver t n e l l i w e w t a a r a p p a voor soor t .then(characteristic => { return characteristic.writeValue( new Uint8Array([ 0x00, r, g, b ); }) ])

r e k i u r b de ge ecteer t sel aat r a p p a t e h

navigator.bluetooth.requestDevice({ filters: [ { namePrefix: ‘PLAYBULB’ } ], optionalServices: [ 0xff0f ] }) .then(device => { …. }) .then(device => device.gatt.connect()) .then(server => server.getPrimaryService(0xff0f)) .then(service => service.getCharacteristic(0xfffc)) z s e s i m o r p 7 1 0 2 o ij z .then(characteristic => { return characteristic.writeValue( new Uint8Array([ 0x00, r, g, b ); ])

let device = await navigator.bluetooth.requestDevice({ filters: [ { namePrefix: ‘PLAYBULB’ } ], optionalServices: [ 0xff0f ] }); .then(device => device.gatt.connect()) .then(server => server.getPrimaryService(0xff0f)) .then(service => service.getCharacteristic(0xfffc)) .then(characteristic => { return characteristic.writeValue( new Uint8Array([ 0x00, r, g, b ); }) ])

let device = await navigator.bluetooth.requestDevice({ filters: [ { namePrefix: ‘PLAYBULB’ } ], optionalServices: [ 0xff0f ] }); r e v r e s e d t e nd m verbi let server = await device.gatt.connect()); let service = await server.getPrimaryService(0xff0f)); let characteristic = await service.getCharacteristic(0xfffc)); e c i v r e s e haal d .then(characteristic => { return characteristic.writeValue( new Uint8Array([ 0x00, r, g, b ); }) ]) c i t s i r e t c a r a h c e d haal

n e e f j i r sch bytes r a pa let let let let device = await navigator.bluetooth.requestDevice({ … }); server = await device.gatt.connect()); service = await server.getPrimaryService(0xff0f)); characteristic = await service.getCharacteristic(0xfffc)); characteristic.writeValue( new Uint8Array([ 0x00, r, g, b ); ])

s e le n e e r a pa s e t by let let let let device = await navigator.bluetooth.requestDevice({ … }); server = await device.gatt.connect()); service = await server.getPrimaryService(0xff0f)); characteristic = await service.getCharacteristic(0xfffc)); let value = await characteristic.readValue(); let r = value.getUint8(1); let g = value.getUint8(2); let b = value.getUint8(3);

r e n e t s i l t n e v e d d a let let let let device = await navigator.bluetooth.requestDevice({ … }); server = await device.gatt.connect()); service = await server.getPrimaryService(0xff0f)); characteristic = await service.getCharacteristic(0xfffc)); characteristic.addEventListener( ‘characteristicvaluechanged’, e => { let r = e.target.value.getUint8(1); let g = e.target.value.getUint8(2); let b = e.target.value.getUint8(3); } ); vergeet niet characteristic.startNotifications(); om te luister en

dingen die je moet weten: • de webbluetooth api • promises (of async await) • typed arrays d ! h u

browser support Chrome Edge (soon) Samsung Servo (soon)

browser support Chrome Edge (soon) Samsung Servo (soon) iOS

browser support a d kin Chrome Edge (soon) Samsung s k r o w Servo WebBLE (soon) for iOS

en… npm install cordova-plugin-webbluetooth

writing a value: function(r, g, b) { return new Uint8Array([ 0x00, r, g, b } ]); reading a value: function(buffer) { return { r: buffer.getUint8(1), g: buffer.getUint8(2), b: buffer.getUint8(3) } } fro g n i d a e r d n a o t g writin c i t s i r e t c a r a h c e m a s e h t m

writing a value: function(r, g, b) { return new Uint8Array([ 0x01, g, 0x01, 0x00, 0x01, b, 0x01, r, 0x01, 0x00 ]); } t n e r r u c e h t g n i read e l b i s s o p t o n s i r colo

writing a value: function(r, g, b) { var buffer = new Uint8Array([ 0xaa, 0x0a, 0xfc, 0x3a, 0x86, 0x01, 0x0d, 0x06, 0x01, r, g, b, 0x00, 0x00, (Math.random() * 1000) & 0xff, 0x55, 0x0d ]); for (var i = 1; i < buffer.length - 2; i++) { buffer[15] += buffer[i]; } } return buffer; t n e r r u c e h t g n i read e l b i s s o p t o n s i r colo

writing a value: function(r, g, b, position) { let buffer = new Uint8Array([ 0x07, 0x02, position + 1, r, g, b ]); } return buffer;

writing a value: function(r, g, b, position) { let buffer = new Uint8Array([ 0x58, r, g, b, 0x01, position ]); …

writing a value: function(r, g, b, position) { let buffer = new Uint8Array([ 0x58, r, g, b, 0x01, position ]); let payload = new Uint8Array(buffer.length + 4); payload[0] = payload.length - 2; payload[1] = payload.length - 2 >>> 8; payload.set(buffer, 2); let checksum = payload.reduce((a, b) => a + b, 0); payload[payload.length - 2] = checksum; payload[payload.length - 1] = checksum >>> 8; let extra = payload.filter(value => {

message[m] = 0x03; message[m + 1] = 0x05; m += 2; } } else if (payload[i] === 0x03) { message[m] = 0x03; message[m + 1] = 0x06; m += 2; } else { message[m] = payload[i]; m++; } message[0] = 0x01; message[message.length - 1] = 0x02; } return message;

log alle bluetooth packets op jouw telefoon b d a k i u r r e b v e o g en om ze etten z e t

m o k r a n h e s e k j r i i k w e b k i e u t r a b ge de dat

de apk decompilen nie l k r e tv ! n e p ap

waarschuwing experimentele technologie n i t h c a w r e v lage n e p p e h c s gen

waarschuwing wifi interferentie ! r e g a l t a w r a a m g o n t a l e d t e z

Niels Leenheer
@nielsleenheer

1 / 90

Time for the browser to get physical. With WebBluetooth the browser can actually take control of all kinds of physical devices in the real world like lightbulbs, robots and even drones. This talk will teach you the basics that you need to get started and will show you some more advanced topics like building your own Bluetooth devices using just JavaScript.

Resources

The following resources were mentioned during the presentation or are useful additional information.

Bluetooth Rocks!

Code for the demos
Bluetooth GATT services

Official standards for Bluetooth services
OpenGatt Registry

Documentation for some proprietary Bluetooth services
Adafruit Bluetooth Sniffer
An Introduction To WebBluetooth

With Progressive Web Apps, you can now use the web to build full-blown apps. Thanks to an enormous amount of new specifications and features, we can do things with the web that you used to need to write native apps for. However, talking to hardware devices was still a bridge too far up till now. Thanks to WebBluetooth, we can now build PWAs that can control your lights, drive a car or even control a drone.

Fun with Bluetooth

Link for this presentation:

HTML code for embedding:

Share on social media:

Resources

Bluetooth Rocks!

Bluetooth GATT services

OpenGatt Registry

Adafruit Bluetooth Sniffer

An Introduction To WebBluetooth