Every wondered how to make your code physically interact with things in the real world? Got a home automation project in mind? In this presentation we will cover: o) How to get started with Raspberry Pi and C# o) The numerous sensors and actuators you can control o) How to navigate basic electronics o) Different interfaces and how to program them o) Demonstrations of devices at work o) Azure IoT Hub to control your code from the cloud and receive live inputs from your device in a Blazor application

1. IoT on Raspberry Pi
John Staveley MVP
16/10/2021
https://uk.linkedin.com/in/johnstaveley/
@johnstaveley

2. About Me
 John Staveley MVP
 IT Contractor in C#, Mvc, Sql Server, Angular and Azure
 Organise LeedsSharp and IoTNorth etc
 Used microcontrollers, Not an electronics expert!

3. What we will cover
 Programming with C# on a Raspberry Pi
 Setup .Net 5
 Control the things
 GPIO, PWM, I2C
 Control from the outside world
 Azure IoTHub
 Receiving updates from the device

4. Hardware Overview
 Raspberry Pi 4-b, Wifi, Camera
port
 GPIO, SPI, USB2/3, Ethernet,
HDMI etc
 MicroSD card and USB-C power
 Meadow
 .Net Nanoframework on ESP32

5. Prepare for launch
 USB-C Power supply (3A)
 Noobs on MicroSD card
 Screen (Micro-HDMI), Keyboard (USB 2/3), Mouse (USB 2/3)
 Wifi (fixed IP)

6. Basic Raspbian setup
 Install .Net 5 https://www.petecodes.co.uk/install-and-use-microsoft-dot-
net-5-with-the-raspberry-pi/
 Install VS Code
 Security settings

7. Control the things
 Digital Input/Output
 PWM
 I2C
 Camera
 Docs for C#: https://github.com/dotnet/iot
 using System.Device.Gpio
 using Iot.Device.Bindings

8. PIN Layout
Ref: https://pinout.xyz/pinout/5v_power#

9. Hello World

10. Digital Output Code
 Install-Package System.Device.IO

11. Digital output examples
 LED
 Buzzer
 Infrared LED
 Laser
 Relay
 Multi-LED
 … and lots more

12. Electronics
 Hardware recipes:
https://gpiozero.readthedocs.io/e
n/stable/recipes.html#led
 Pull up/down
 Anti-short
 Anti back EMF diodes
 Geekcreit 45 In 1 Sensor Module
Board Starter Kits Upgrade
Version For Arduino (Banggood
£15)
 https://images-eu.ssl-images-
amazon.com/images/I/C1lrpIfADa
S.pdf

13. Azure IoT Hub
 Free for < 8000 messages per day
 Control hundreds of devices
 Event Hubs
 HTTP, AQMP, MQTT
 Device Twins
 IoT Edge
 Setup:
 Create IoTHub in Azure portal
 Create device in portal
 Set up a direct method

14. DEMO
Controlling using Azure IoT
Explorer

15. Connecting device to Azure IoT Hub
 Get DEVICE connection string from IoTHub
DeviceClient _deviceClient =
DeviceClient.CreateFromConnectionString(configuration.IoTHubConnect
ionString);
await _deviceClient.SetMethodHandlerAsync(“MyMethod”, ActionMethod,
null);
….
private static async Task<MethodResponse>
ActionMethod(MethodRequest methodRequest, object userContext)
{
var data = methodRequest.DataAsJson;
var controlAction =
JsonConvert.DeserializeObject<ControlAction>(data);

16. Development experience
 Develop in Visual Studio
 Publish to directory
 Deployment: self-contained
 Target runtime: linux-arm
 Target framework: net5.0
 Fixed IP
 SFTP files using FileZilla
 VNC
 chown <user> <Directory or File> e.g. chown pi ./Control
 chmod +rwx <Directory> e.g. chmod +rwx ./Control
 ./<My dll name> e.g. ./Control

17. Digital input examples
 Push button
 Reed switch
 Magnetic sensor
 Tilt switch
 Ball switch
 Knock sensor
 Light blocking
 Infrared receiver
 Motion sensor

18. Pulse-width Modulation
(PWM)

19. Pulse-width Modulation
Examples
 Servos
 Lamps/LED
 Motors
 Pumps
 Fan
 Display Dial
 Audio effects https://www.youtube.com/watch?v=l4cuy1HOR3E
 …and lots more

20. Pulse-width Modulation Setup

21. PWM Code
 Software PWM
 Hardware PWM
var _servo1 = new SoftwarePwmChannel(18, 400, 0.9, true);
_servo1.Start();
_servo1.DutyCycle = 0;
_servo1.DutyCycle = 50;
_servo1.DutyCycle = 100;

22. I2C Overview
 Inter-Integrated Circuit (I2C)
 Two wire communication
 Pin 3, 5 and 27, 28
 Short range, multiple devices
 Enable on hardware
 sudo apt-get install i2c-tools
 sudo i2cdetect –y 1

23. I2C Examples
 Relay controller
 PWM controller
 Digital IO Expansion
 LCD screen
 Analogue inputs
 GPS
 RFID
 Rotary encoder (Volume switch)
 Temperature, Pressure, Humidity
 Accelerometer
 EEPROM

24. Aside:
Prototyping
 Jumper cables (M-F, F-F)
 Din rail mounting
 Connector blocks
 Breadboard
 Totemmaker

25. I2C Hardware – PWM controller

26. I2C PWM controller - code

27. Choosing hardware
 https://shop.pimoroni.com
 https://github.com/dotnet/iot/tree/
main/src/devices
 No driver? Translate the I2C interface!

28. I2C Relay Hat
 Solenoids
 High ampage lamps
 Fireworks
 …See code in project

29. I2C Relay hat - code
// Set relay 0 to 3, control Action 0 or 1
// Get relayNumber 0 to 3, returns either 0 or 1
… see code e.g. SetRelay

30. Introducing Blazor
 SPA Application framework
 Server side
 Push updates by SignalR

31. Blazor – how it works

32. Sending a message to Azure IoT Hub
 Get SERVICE connection string
ServiceClient _serviceClient =
ServiceClient.CreateFromConnectionString(configuration.IoTHubConnec
tionString);
var deviceMethod = new CloudToDeviceMethod(“MyMethod”);
var payload = JsonSerializer.Serialize(controlAction);
deviceMethod.SetPayloadJson(payload);
var result = await
_serviceClient.InvokeDeviceMethodAsync(_deviceId, deviceMethod);

33. DEMO
Putting it together: Website
controlling remote device

34. Camera
 Normal, Hi-def, infra-red

35. Digital Input example

36. Digital Input code
int _inputPin = 22;
System.Device.Gpio.GpioController _controller = new();
_controller.OpenPin(_inputPin, PinMode.Input);
var inputResult = _controller.Read(_inputPin);
Console.Log(inputResult); // High or Low

37. Sending messages from the device
 …to the event hub

38. Event Hubs
 Azure IoTHub is backed by an
Event Hub
 Scalable to millions of events
per second
 Kafka as a service
 Supports AMQP, HTTPS and
Apache Kafka

39. Receiving messages from Event Hub
 Messages can be routed to blob storage/service bus etc
 IoTHub -> Message Routing -> Enable fallback route
 Receive message from Event Hub

40. Demo: Receiving events from device
 Device started
 Is alive
 Button push

41. Summary
 You have the power using C# to control lots of types of hardware: I/O, PWM,
I2C, Camera
 Not everything you can buy can be controlled – yet!
 Azure IoT Hub can be used to connect to and control your device from the
internet and receive live events from it

42. Get started
resources
 Starter kit:
https://thepihut.com/products/r
aspberry-pi-starter-kit
 “How to” book:
https://shop.pimoroni.com/produ
cts/the-official-raspberry-pi-
beginners-guide-4th-ed-uk
 45 in 1 sensor pack:
https://www.banggood.com/Gee
kcreit-45-In-1-Sensor-Module-
Board-Starter-Kits-Upgrade-
Version-For-Arduino-UN0-R3-
MEGA2560-Plastic-Bag-Package-p-
1137050.html

43. Any Questions?
@johnstaveley
Demo code: https://github.com/johnstaveley/RaspberryPiControl
Slides: https://www.slideshare.net/johnstaveley/iot-on-raspberry-pi
Connect: https://uk.linkedin.com/in/johnstaveley/