The Internet of Things (IoT) is fundamentally changing how we interact with the digital world. In this session we’ll explore the implementation of real examples which bridge the gap between the physical and digital world using PHP: asking Alexa for information within a PHP application; displaying API data on an Arduino-powered display; using PHP to control LEDs on a Raspberry Pi to monitor application uptime; and connecting IR sensors to Slack to see whether a conference room is in use.

1. Rise of the Machines:
PHP & IoT
@colinodell

2. Colin O’Dell
• Lead Web Developer at Unleashed Technologies
• PHP League Leadership Team
• Baltimore PHP Co-Organizer
• Arduino & Raspberry Pi Enthusiast
@colinodell

3. Goals
• Introduce the basics of building custom IoT devices
• Understand where web technologies fit in
• Four real-world example projects
@colinodell

4. Internet of Things
The Internet of Things is the internetworking of physical devices,
vehicles, buildings and other items—embedded with electronics,
software, sensors, actuators, and network connectivity that enable
these objects to collect and exchange data.
- https://en.wikipedia.org/wiki/Internet_of_things
@colinodell

5. Internet of Things
The Internet of Things is the internetworking of physical devices,
vehicles, buildings and other items—embedded with electronics,
software, sensors, actuators, and network connectivity that enable
these objects to collect and exchange data.
- https://en.wikipedia.org/wiki/Internet_of_things
@colinodell

6. Connectivity
• Ethernet / WiFi
• NFC / RFID
• Bluetooth LE
• Zigbee / Z-Wave
• Cellular (LTE / CDMA / GSM)
• …and many others
@colinodell

7. 0
10
20
30
40
50
60
2003 2010 2015 2020
(Billions) Population vs Connected Devices
People Connected Devices
@colinodellSource: https://www.cisco.com/c/dam/en_us/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf

8. @colinodell

9. @colinodell

10. What We’ll Cover
• Device overview
• Four examples of combining IoT with PHP
 Project Goals
 Hardware & Platform Choice
 Building the device
 Demo*
• Q&A
@colinodell

11. DIY IoT Devices
For the software or hardware enthusiast
@colinodell

12. @colinodell

13. How to choose?
• Identify required features
• Ideal programming language
• Consider power requirements
• Size / footprint
@colinodell

14. Four Examples Using PHP
@colinodell

15. Uptime Monitor
Use Raspberry Pi to monitor if site is up; change LED color accordingly
@colinodell

16. Why Raspberry Pi?
• Internet connectivity
 Handles HTTPs out-of-the-box
• Runs Linux (Raspian – a derivative of Debian)
 PHP easily installed
• Has GPIO pins
• Raspberry Pi Zero only $5
• Why not?
@colinodell

17. Hardware
@colinodell
• Raspberry Pi (any variant)
• Micro USB cable (power)
• USB WiFi dongle
• Micro SD card
• RGB LED
• Two resistors
• Wires

18. RGB LEDs
@colinodell

19. Wiring
@colinodell

20. @colinodell
$ composer require piphp/gpio

21. @colinodell
<?php
const URL = 'https://www.colinodell.com';
const GPIO_PIN_GREEN = 12;
const GPIO_PIN_RED = 16;
require_once 'vendor/autoload.php';
$gpio = new PiPHPGPIOGPIO();
$greenLed = $gpio->getOutputPin(GPIO_PIN_GREEN);
$redLed = $gpio->getOutputPin(GPIO_PIN_RED);
$httpClient = new GuzzleHttpClient();
while (true) {
try {
$response = $httpClient->head(URL, [
'connect_timeout' => 3,
'timeout' => 3,
]);
echo URL . " is onlinen";
$greenLed->setValue(1);
$redLed->setValue(0);
} catch (RuntimeException $ex) {
echo URL . " is OFFLINE!n";
$greenLed->setValue(0);
$redLed->setValue(1);
}
sleep(3);
}

22. @colinodell
HTTP Server for
colinodell.com
Raspberry Pi
Terminal (SSH)
Live view of
colinodell.com

23. Recap
• PHP on a Raspberry Pi
• PHP checks if site is up
• PiPHP/GPIO library used to control output pins (LEDs)
Other uses for output pins:
• Control motors/servos
• Control relays (turn higher-voltage things on/off)
• Drive digital displays (LCD screens, LED number displays, etc.)
@colinodell

24. Conference Room
Occupancy Sensor
Raspberry Pi detects movement in room; sends room status to Slack
@colinodell

25. Why Raspberry Pi?
• Runs Linux (Raspian – a derivative of Debian)
• Has GPIO pins
• PHP easily installed
• Raspberry Pi Zero only $5
• Handles HTTPs out-of-the-box
• Why not?
@colinodell
TL;DR: Same reasons as before!

26. Hardware
@colinodell
• Raspberry Pi (any variant)
• Micro USB cable (power)
• USB WiFi dongle
• PIR Sensor
• Wires

27. PIR Sensors
@colinodellImages from https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/overview

28. Wiring
@colinodell

29. @colinodell

30. Signal
@colinodell
Motion Detected
Occupied Vacant Occupied

31. @colinodell
<?php
namespace ColinODellPHPIoTExamplesPHPPIRSensor;
class Room
{
/**
* @var bool
*/
private $occupied = false;
/**
* @var int
*/
private $lastMovement;
/**
* @var callable
*/
private $onRoomStateChange;
/**
* @var int
*/
private $roomEmptyTimeout;
/**

32. @colinodell
<?php
// Configuration:
const GPIO_PIN = 17;
const DECLARE_ROOM_EMPTY_AFTER = 60*5; // 5 minutes
const SLACK_INCOMING_WEBHOOK_URL = 'https://hooks.slack.com/services/xxxx/xxxx/xxxx';
// End configuration
require_once 'vendor/autoload.php';
use ColinODellPHPIoTExamplesPHPPIRSensorRoom;
use PiPHPGPIOGPIO;
use PiPHPGPIOPinInputPinInterface;
// HTTP client for communicating with Slack
$http = new GuzzleHttpClient();
// Instantiate a new room object to keep track of its state
$room = new Room();
$room->setRoomEmptyTimeout(DECLARE_ROOM_EMPTY_AFTER);
$room->setOnRoomChangeCallback(function($isOccupied) use ($http) {
$message = 'The conference room is now ' . ($isOccupied ? 'occupied.' : 'vacant.');
$http->postAsync(SLACK_INCOMING_WEBHOOK_URL, [

33. @colinodell

34. Recap
• PHP on a Raspberry Pi
• PiPHP/GPIO library monitors GPIO pin for signal changes
• PHP tracks duration between rising edges (low-to-high signal changes)
• Notifications pushed to Slack via webhook
Other uses for input pins:
• Switches & buttons
• Sensors (temperature, humidity, motion, accelerometer, GPS)
• Receiving data from other devices
@colinodell

35. Alexa Custom Skill
Use PHP + Laravel to handle request for ZendCon session information
@colinodell

36. @colinodell

37. Why Alexa / Amazon Echo?
• Amazon handles voice recognition
• Parsed request passed from Amazon to our API endpoint
• We handle accordingly; send formatted response for Alexa to read aloud
• Published skills easily installable
@colinodell

38. User Interaction Flow
@colinodellDiagram from https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/overviews/understanding-custom-skills

39. Invoking Custom Skills
• Ask [skill name] [action] Ask ZendCon which sessions are next
• Tell [skill name] [action] Tell ZendCon this talk is great
• [action] using [skill name] Rate this talk 5 stars using ZendCon
@colinodell

40. Actions
• What sessions are next?
• What session is next in {room}?
• What sessions are at {time} in {room}?
• Who is speaking in {room} {day} at {time}?
@colinodell

41. Defining Actions
GetSessions what sessions are next
GetSessions what talks are next
GetSessions who is talking next
GetSessions who is speaking next
GetSessions which sessions are next
GetSessions which talks are next
GetSessions what session is next in {room}
GetSessions what talk is next in {room}
GetSessions who is talking next in {room}
GetSessions who is speaking next in {room}
GetSessions which session is next in {room}
GetSessions which talk is next in {room}
GetSessions what sessions are at {time}
GetSessions what talks are at {time}
GetSessions who is talking at {time}
GetSessions who is speaking at {time}
GetSessions which sessions are at {time}
GetSessions which talks are at {time}
GetSessions what sessions are at {time} {day}
GetSessions what talks are at {time} {day}
GetSessions who is talking at {time} {day}
GetSessions who is speaking at {time} {day}
GetSessions which sessions are at {time} {day}
GetSessions which talks are at {time} {day}
GetSessions what session is in {room} at {time}
GetSessions what talk is in {room} at {time}
GetSessions who is talking in {room} at {time}
GetSessions who is speaking in {room} at {time}
GetSessions which session is in {room} at {time}
GetSessions which talk is in {room} at {time}
GetSessions what session is in {room} at {time} {day}
GetSessions what talk is in {room} at {time} {day}
GetSessions who is talking in {room} at {time} {day}
GetSessions who is speaking in {room} at {time} {day}
GetSessions which session is in {room} at {time} {day}
GetSessions which talk is in {room} at {time} {day}
GetSessions what session is {day} in {room} at {time}
GetSessions what talk is {day} in {room} at {time}
GetSessions who is talking {day} in {room} at {time}
GetSessions who is speaking {day} in {room} at {time}
GetSessions which session {day} is in {room} at {time}
GetSessions which talk {day} is in {room} at {time}
@colinodell

42. Intent Schema
@colinodell
{
"intents": [
{
"intent": "GetSessions",
"slots": [
{
"name": "day",
"type": "AMAZON.DATE"
},
{
"name": "time",
"type": "AMAZON.TIME"
},
{
"name": "room",
"type": "ROOM"
}
]
},
{
"intent": "AMAZON.HelpIntent"
}
]
}
The Joint
Artist C
Artist D
Artist E
Artist F
Artist G
Artist H

43. @colinodell
$ composer require develpr/alexa-app
AlexaRoute::intent('/alexa-end-point', 'GetDeveloperJoke', function(){
Alexa::say("A SQL query goes into a bar, walks up to two tables and asks, "Can I join you?"");
});

44. @colinodell
// TODO: Import schedule to MySQL database

45. @colinodell
<?php
namespace AppHttpControllers;
use CarbonCarbon;
use DevelprAlexaAppFacadesAlexa;
use DevelprAlexaAppRequestAlexaRequest;
use IlluminateDatabaseQueryBuilder;
use IlluminateSupportFacadesDB;
class SessionController extends Controller
{
public function getSessions(AlexaRequest $request)
{
$request->getIntent();
$time = $request->slot('time') ?: Carbon::now()->format('G:i');
$day = $request->slot('day') ?: Carbon::now()->format('Y-m-d');
$room = $request->slot('room');
try {
$sessions = $this->findSessions($time, $day, $room);
if (count($sessions) === 0) {
// No sessions found
return Alexa::say('Sorry, I couldn't find any sessions on ' . $day . ' at ' . $time)->endSession();
} elseif (count($sessions) === 1) {
return Alexa::say($this->getSessionText(reset($sessions)))->endSession();;
} else {
$text = 'I found ' . count($sessions) . ' sessions. ';
foreach ($sessions as $session) {

46. @colinodell
<?php
// app/Http/routes.php
AlexaRoute::intent('/alexa', 'GetSessions', 'AppHttpControllersSessionController@getSessions');

47. Recap
• Alexa parses voice request; passes to PHP
• Laravel application handles requests; returns response
• Alexa renders responses as voice and/or cards
Other uses for Alexa:
• Querying for information
• Interactive sessions (online ordering, games, etc.)
• Home automation
@colinodell

48. Packagist Download Counter
Displaying downloads counts from the Packagist API with Particle Photon
@colinodell

49. Particle Photon
@colinodell
• WiFi built in
• Small footprint
• Can be powered via MicroUSB
• Enough digital GPIO pins
• Programmable via web-based IDE
• OTA flashing
• Built-in webhook support

50. Hardware
@colinodell
• Particle Photon
• MAX7219 8-Digit Red LED Display Module
• Micro USB cable (power)
• Wires

51. MAX7219 8-Digit Red LED Display Module
@colinodellImages from https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/overview

52. Wiring
@colinodell

53. @colinodell

54. @colinodell

55. @colinodell

56. Problem!
• JSON document is 32.5 KB
• Photon webhook responses are 512-byte chunks spaced 250ms apart
@colinodell

57. Problem!
• JSON document is 32.5 KB
• Photon webhook responses are 512-byte chunks spaced 250ms apart
@colinodell
Solution!
• Use Yahoo YQL to reduce response size

58. Problem!
• JSON document is 32.5 KB
• Photon webhook responses are 512-byte chunks spaced 250ms apart
@colinodell
Solution!
• Use Yahoo YQL to reduce response size
• Use PHP to parse JSON, return just one number

59. packagist-counter.php
@colinodell
<?php
const URL = 'https://packagist.org/packages/league/commonmark.json';
$json = json_decode(file_get_contents(URL), true);
header('Content-Type: text/plain');
echo $json['package']['downloads']['total'];

60. @colinodell

61. @colinodell

62. @colinodell

63. @colinodell

64. Recap
• Particle Photon + 8 digit LED display
• Particle webhook fetches data from packagist-counter.php
• packagist-counter.php fetches from packagist.org; trims out the fat
@colinodell

65. Summary
@colinodell

66. Summary
• IoT is everywhere!
• PHP can bridge the gap
• Run PHP:
 On the device (RasPi examples)
 In “the cloud” (Alexa; Particle Photon)
 Or both!
• Anyone can build web-connected devices
@colinodell
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67. Questions?
Project Source Code / Documentation:
https://github.com/colinodell/php-iot-examples
Even More Projects:
https://www.hackster.io
Building Robots with PHP:
Christopher Pitt @ The Joint (next session)
@colinodell
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