This document provides an overview and introduction to the Web of Things (WoT). It begins with definitions of key IoT concepts like embedded devices, sensors and actuators. It then covers networking protocols for IoT including LPWAN. The main part of the document focuses on the WoT, including its key aspects of the Access, Find, Share and Compose layers. It provides examples of using APIs and semantic models to represent IoT devices on the web. Labs are suggested to experiment with programming IoT devices and creating mashups using tools like Node-RED and IFTTT. Overall the document serves as a high-level tutorial introducing important WoT concepts and technologies.

1. From the
Internet of
Things to the
Web of Things

2. Hello!
I am Dr. Dom Guinard
Co-invented the WoT, Co-Founded
EVRYTHNG & loves: Web technologies,
standards, startups, books and mountains!
@domguinard
2

3. If I tell you...
✗ NPM
✗ GPIOs
✗ PIR
✗ LPWAN
✗ MQTT
✗ WoT
✗ REST
✗ Websockets
✗ NodeRED
✗ IFTTT
✗ Ethereum
✗ Tensorflow
3

4. What’s in the course?
The IoT, the WoT
History, applications, ...
Getting started with
embedded devices
Sensors, actuators, devices, GPIOs,
...
The I in IoT
Networking layers and protocols,
Zigbee, Bluetooth, LPWAN, WiFi,
etc.
4
The W in IoT:
Web of Things!
Architecture, layers, API for Things
Layers of the WoT
Access, Find, Share, Compose
The Future of the IoT
From blockchain to AI and other
buzzwords & challenges ahead for
the IoT

5. The Web of Things Book!
Course largely based on the book
Books and kits options on:
http://book.webofthings.io
Use 39guinard
To get 39% discount on Manning
5

6. 1. The IoT

7. “[...] the phrase "Internet of Things"
started life as the title of a
presentation I made at Procter &
Gamble (P&G) in 1999. Linking the
new idea of RFID in P&G's supply
chain to the then-red-hot topic of
the Internet [...]”
[@Kevin_Ashton]
7

8. 8

9. 9
1. (Unique) Identity
2. Connectivity to Internet
Protocols: directly or via a gateway
3. Sensing
4. and / or Actuation

10. Application Domains
Consumer IoT
Smart homes, quantified
self, wearables, consumer
marketing, assisted living,
etc.
Commercial IoT
Smart supply chains,
smart buildings,
connected medical
devices, connected cars,
etc.
Industrial IoT
Smart cities, smart grids,
Industry 4.0, smart
manufacturing
10

11. Examples @EVRYTHNG
11

12. More examples!
12

13. Remember IoT != smart home! @EVRYTHNG Examples
13

14. Lab: Setting up your Pi!
14
See also: Chapter 4, page 94
1. Install Etcher from https://etcher.io
2. Install your Pi:
https://webofthings.org/wot-book-pi-image/

15. 2. Getting
started with
embedded
devices

16. 16
VS
Multicores (ARM)
32-64 Bits
X GB of RAM
X GB of Flash
Microcontroller
8-16 Bits
X KB of RAM
X KB of ROM

17. 17

18. 18
Espruino
Edison
Tessle
Artik
Kinoma
Beaglebone
Raspberry Pi
(Pi Zero incl.)

19. 19
Why JS & Node on embedded devices?

20. Lab 1: A Webserver on a Pi!
20
See also: Chapter 3 & Chapter 4, page 94
1. Connect your Pi to the network
a. ping raspberrypi.local and write
down your IP
2. Build your (first?) Node HTTP server on the Pi (page
64)
3. Bonus: Install NVM & Node.js on your computer
a. curl -o-
https://raw.githubusercontent.com/creationix/nvm
/v0.33.2/install.sh | bash
b. nvm install v4.9.1
4. Bonus: build a more advanced server, see Listing
3.2 page 66

21. Lab Notes: Headless setup
21
✗ Change MDNS hostname of your Pi:
✗ sudo nano /etc/hostname
✗ Headless SSH:
✗ Add: /boot/ssh
✗ Headless config of the wifi:
✗ Add: /boot/wpa_supplicant.conf

22. Some key points so far...
✗ IoT came from RFID in 1999
✗ The Things in the IoT typically have 4 properties:
✗ Identity
✗ Connectivity
✗ Sensing
✗ Actuating
✗ There are 2 world of embedded devices:
✗ Linux Devices (ARM, e.g., Pi)
✗ Microcontrollers (e.g., Marvell, TI)
✗ Javascript (Node) is taking over things for prototyping
22

23. 3. Sensors &
Actuators
(via GPIOs)

24. 24
1. Sensors:
a. Temperature / Humidity
b. PIR
2. Actuators:
a. LEDs
b. Screens
c. Relays (switches)

25. 25

26. 26
http://johnny-five.io
https://github.com/fivdi/onoff
https://github.com/intel-iot-devkit/mraa https://cylonjs.com/
http://ni-c.github.io/heimcontrol.js/
https://github.com/webofthings/webofthings.js

27. 27
var Gpio = require('onoff').Gpio,
sensor = new Gpio(17, 'in', 'both'); //#A
sensor.watch(function (err, value) { //#B
if (err) exit(err);
console.log(value ? 'there is someone!' : 'not anymore!');
});
function exit(err) {
if (err) console.log('An error occurred: ' + err);
sensor.unexport();
console.log('Bye, bye!')
process.exit();
}
process.on('SIGINT', exit);
// #A Initialize pin 17 in input mode, 'both' means we want to handle both rising and falling interrupt edges
// #B Listen for state changes on pin 17, if a change is detected the anonymous callback function will be called with the
new value

28. 28

29. Lab 2: GPIOs
29
See also: Chapter 4, from page 102
1. Setup the PIR sensor (see page 104)
2. Connect it to onoff.js code (see
chapter4-gpios/pir.js)
3. Bonus: setup the DHT sensor (see Chapter 4 from
page 105)

30. 4. The I in IoT:
The Networks

31. Categories of protocols
PAN: Personal Area Net
WiFi, Zigbee, Enocean,
Thread, Bluetooth, etc.
Usually for consumer IoT:
Smart homes, smart
buildings, beacons, etc.
(LP)WAN: Low Power
Wide Area Net
SigFox, LoRA, 5G, NB-IoT,
CAT-M, etc.
Usually for industrial &
commercial IoT:
Smart cities, supply chain
tracking, smart meters,
etc.
31

32. 32
Good reasons for no IP+Web end-to-end
Battery Powered Devices Deployment requires a mesh

33. 33

34. 34

35. The emergence of LPWANs
✗ New networks created for the IoT
✗ Smart meters, Supply chain
tracking
✗ LP = Low Power
✗ 3 big categories:
✗ SigFox (the first)
✗ LoRA (the more “open” - see
TheThingsNetwork)
✗ 5G IoT (the “operators”)
✗ CAT-M
✗ NB-IoT
35

36. Demo: LPWAN & TTN
36
✗ Using a TTN Node
✗ Communicating with EVRYTHNG

37. Some key points so far...
✗ Sensors and Actuators are integrated to IoT
prototypes (and products) via GPIOs
✗ There are a lot of networking technologies involved in
the IoT. In particular because of the energy
consumption of WiFi and need for mesh.
✗ Very low-power protocols are emerging (LPWAN)
37

38. 5. The W in IoT:
The Web of
Things

39. “The IoT is a science primarily
focusing on creating the
most complex ways of
turning lights on.”
[@domguinard]
39

40. 40
+
Pre IoT

41. 41
+
Post IoT

42. 42
Enters the Web of Things!

43. 43
Great but it was 2007...

44. “The Web on Devices? Yeah,
sure… NOT!”
[@theEmbeddedCommunity,
2007]
44

45. 45

46. 46
And then… it clicked :)

47. 47

48. 5.1 Access:
The API of
Things

50. Dom Guinard
CTO & Co-founder

51. 51
$(document).ready( //#A
function doPoll() {
$.getJSON('http://devices.webofthings.io/pi/sensors/temperature', //#B
function (data) { //#C
console.log(data);
$('#temp').html(data.value + ' ' + data.unit); //#D
setTimeout(doPoll, 5000); //#E
});
});
//#A Wait until the page is loaded and then call doPoll()
//#B Use the AJAX helper to get the JSON payload from the temperature sensor
//#C When the response arrives, this function is called
//#D Select the "temp" HTML element and update its content using the data.value (the value) and data.unit
(the unit) returned in the JSON payload
//#E The doPoll() function sets a timer to call itself again in 5 seconds (5000 milliseconds)

52. Lab 3: Talking Web to a Thing!
52
✗ Fork & Clone the book code on your machine
✗ git clone https://github.com/webofthings/wot-book
--recursive
✗ Browse the device as a Human on:
http://devices.webofthings.io/
✗ Install Postman and browse the device as an App
✗ URL: http://devices.webofthings.io/
✗ Accept: application/json
✗ Modify 2.2 code to get the humidity value every 5
seconds
✗ Bonus: change the type of graph in 2.2

53. Web API for Things: 5 Steps
A. Resource design—Identify the functionality or services
of a Thing, and organize the hierarchy of these services.
B. Representation design—Decide which representations
will be served for each resource.
C. Interface design—Decide which commands are possible for
each service, along with which error codes.
D. Resource linking design—Decide how the different
resources are linked to each other.
E. Integration strategy—Choose a pattern to integrate
Things to the internet and the web.
53

54. Resources,
Representations
& Links

55. 55
Request:
GET /pi
Host:
devices.webofthings.io
Accept: application/json
Response:
200 OK
Content-Type:
application/json
{
"name" : "Pi"
...
} 1. Resource design
2. Representation design
3. Interface design
GET
PUT
4. Linking
Design

56. 56
Resources on the WoT Pi

57. 57
Beyond HTTP: Websocket for events

58. 58
function subscribeToWs(url, msg) {
var socket = new WebSocket(url);
socket.onmessage = function (event) {
console.log(event.data);
};
socket.onerror = function (error) {
console.log('An error occurred while trying to connect to a Websocket!');
console.log(error);
};
socket.onopen = function (event) {
if (msg) {
socket.send(msg);
}
};
}
//subscribeToWs('ws://localhost:8484/pi/sensors/pir);

59. 59
Software architecture on the WoT Pi

60. Lab 4: Designing the Pi API
60
✗ See also: Chapter 7
✗ Code deep-dive together
✗ chapter7-implementation/part1-2-direct-gateway
✗ Resources (add a noise sensor)
✗ Representation (see messagepack)
✗ Adding a representation
✗ Add CBOR support
✗ npm install --save cbor
✗ In converter.js
✗ Bind PIR sensor on your Pi
✗ Communication via WebSocket
✗ chapter2-hello-wot/client/pir-websockets.html
✗ Bonus: bind the DHT sensor of your Pi (see page 183)

61. Step 5:
Integration
Strategy

62. 62
The Web on Devices!

63. 63
But not all things can speak Web!

64. 64
An Example with the EVRYTHNG Platform

65. 65
The Web on Devices!

66. 66
The Web on Devices!

67. Lab 5: Gateways
67
✗ See also: Chapter 7, page 195
✗ CoAP
✗ Start the CoAP server
✗ Look into the plugin
✗ Request a CoAP resource via HTTP:
✗ /things/coapDevice/sensors/co2
✗ EVRYTHNG Demo
✗ Bonus: connect your PIR sensor to EVRYTHNG

68. 5.2 Find:
The Findability
of Things

70. 70
The issues with Finding Things!

71. 3 Challenges in IoT Findability
What’s the Bootstrap
URL?
mDNS
What’s the format I should
expect (syntax)?
REST, JSON, WoT Model
What does that mean
(semantics)?
W3C WoT, Schema.org
IoT
71

72. How to find the URL of a Thing? mDNS!
service up: {
interfaceIndex: 4,
type:
{ name: 'http',
protocol: 'tcp',
subtypes: [],
fullyQualified: true },
replyDomain: 'local.',
flags: 3,
name: 'Brother MFC-8520DN',
networkInterface: 'en0',
fullname:
'Brother032MFC-8520DN._http._tc
p.local.',
host: 'EVT-BW-BROTHER.local', The
service
port: 80, local IP address
addresses: [ '192.168.0.6' ]
}
72
✗ mDNS clients listen for mDNS
messages (on UDP)
✗ DNS tables are populated from
what they catch
✗ Your Pi broadcasts mDNS
messages as we speak!

73. 73
http://model.webofthings.io
http://gateway.webofthings.io

74. 74
The issues with Finding Things!

75. 75
The Web Thing Model in a Nutshell

76. The WoT Model Continues @ W3C
{
"@context": ["http://www.w3.org/ns/td",
{"iot": "http://iotschema.org/"}],
"@type" : "Thing",
"id": "urn:dev:wot:com:example:servient:lamp",
...
"security": [{"scheme": "psk"}],
"properties": {
"status": {
"@type" : "iot:SwitchStatus",
"description" : "Shows the current status of the
lamp",
"writable": false,
"observable": false,
…
"actions": {
"toggle": {
"@type" : "iot:SwitchStatus",
"description" : "Turn on or off the lamp",
"forms": [{
"href": "coaps://mylamp.example.com/toggle",
"mediaType": "application/json"
76
✗ Model:
✗ Things
✗ Properties
✗ Actions
✗ Events
✗ Extensible via
SemanticWeb
✗ https://schema.org
https://w3c.github.io/wot-thing-description/

77. Lab 6: Semantic Web of Things
77
✗ See also: Chapter 8
✗ Experiment with the Web Thing Model in Action:
Automatic UI generation, use
✗ Use the wot.js server in chapter8-semantics
✗ http://IP:8484/model
✗ Test the client:
chapter10-mashups/UI/UI.html
✗ Bonus:
✗ Bind an LED on your Pi to react to Actions
✗ Play Mozilla Things Project, a modern
implementation of the Web Thing Model

78. 5.3 Secure &
Share

80. Basic Principles of IoT Security
Over the air
updates
TLS
Communication
Device
Authentication
80

81. Securing Things (over simplified!)
81
✗ Problem 1:
✗ TLS Web Encryption
✗ Problem 2:
✗ SSL (TLS) certificates
✗ Problem 3:
✗ API keys (oAuth)
✗ TLS certificates on device

82. 82
Sharing in the Web of Things!

83. Lab 7: Secure & Share Things
83
✗ See also: Chapter 9
✗ Securing our server
✗ Encryption:
✗ openssl req -sha256 -newkey rsa:4096
-keyout privateKey.pem -out caCert.pem
-days 1095 -x509
✗ Try: https://localhost:8484/pi/
✗ Secure proxy with Ngrok:
✗ Put your Pi on the Web with Ngrok
✗ wget
https://bin.equinox.io/c/4VmDzA7iaHb/ngrok-stabl
e-linux-arm.zip
✗ ./ngrok http 8484
✗ Bonus:
✗ Test the social WoT proxy (from page 260)

84. 5.4 Compose:
Physical Mashups

86. 86
Mashup for Things - Node-RED

87. 87
IFTTT: Wizard based mashups

88. Lab 8: Composing Things
88
✗ See also: Chapter 10
✗ Create an IFTTT mashup that
✗ Sends a turn LED on Action to your WoT Pi
✗ Connect our PIR sensor to Node-RED (see page 293)
✗ Launch the unsecure version (chapter 8)
✗ Node-red
✗ Connect to:
ws://IP:8484/properties/pir
✗ Bonus:
✗ Implement the full Node-RED mashup (see page
292)
✗ Try the full JS mashup of chapter 2:
ex-5-mashup.html

89. Links
✗ Web of Things Community
✗ WoT @ W3C and WoT W3C Architecture
✗ Mozilla WoT
89

90. 6. The Future of
Things

91. IoT’s challenges & the Future!
1. Interoperability
✗ The (semantic) Web can help!
2. Scalability
✗ Decentralization will be key (blockchain)
✗ Dealing with the data overload (machine learning)
3. Privacy
✗ GDPR, Data marketplace
4. Security
✗ Use Web security, prepare for Quantum computing!
5. Durability
✗ Regulation, IoT Mark
6. Usability
✗ The disappearing computer
91

92. Key takeaways
✗ The IoT is here and now, 20 billion connected objects
expected to join by 2022, enormous opportunity
but significant challenges
✗ Networks are evolving to support the special needs
of Things
✗ Interoperability is key, the Web can help at many levels
92

93. 93
Thanks!
You can find me at:
✗ @domguinard
✗ dom@guinard.org
✗ http://dom.guinard.org
✗ https://webofthings.org

94. SlidesCarnival icons are editable shapes.
This means that you can:
● Resize them without losing quality.
● Change fill color and opacity.
Isn’t that nice? :)
Examples:
94