Prototype Board Hardware: Photo-Resistor and LED

The photo resistor and the 1 kΩ resistor form a voltage divider

The LED can be switched on by program and changes the light
Intensity seen by the photo resistor

Slide 1: What is IoT?

An Introduction

Uli Raich (uli.raich@gmail.com)

Formally CERN, Geneva, Switzerland

Slide 2: What is IoT?

Answer: IoT is the Internet of Things
But… what is the Internet of Things?

I hate buzz-words!

Everybody talks about IoT but who does deeply know,

what is hidden behind the acronym.

Who is able to set up an IoT by himself?

Slide 3: The child and the elephant

Child: “What is an elephant”

Me: An elephant is a grey animal!

Result:

• The child has got an answers and does not disturb me any longer
  
  
• The child thinks that I am clever, because he thinks
  
  I know what an elephant is (which is not true!)
  
  
• The child does not know much more than before asking

Slide 4: What should I have done?

• Learned about elephants myself
  
  
• Told him everything about elephants I know myself:
  
  
  • Where and how they live
    
    
  • What they eat
    
    
  • How they behave …
    
    
• Gone to the zoo (in Europe) or a nature reserve (here in East Africa)
  
  to show him a live elephant.

Slide 5: What is the “I” in IoT ?

The “I” stands for Internet. This means:

We need a processor (IoT node) that can connect to the Internet.

It must be powerful enough to run Internet protocols and

it needs an interface to the Internet.

• Ethernet interface
  
  
• WiFi interface
  
  
• GSM
• … connection to a gateway with access to the internet

Slide 6: Standard way to access the Internet

Usually the Internet is used by humans

Typical applications are

• WEB browsing
  
  
• Email
  
  
• Social media
  
  
• Telephone and chats

Slide 7: Things, Sensors, Actuators

• Coffee machines, dish washer, washing machine, …
• Burglar alarm system
• Intelligent farming
• Weather station
• Scientific measurements
• Industrial factory control
• Car electronics, ignition system, ABS,…
• You name it!

Our processor needs interfaces to these sensors and actuators.

Slide 8: The IoT system

We need a system with a number of processors

that read out sensors and/or control actuators

These processors communicate with each other

over the Internet with or without human intervention.

Design decisions:

• Which processors?
• Which communication protocol
• Which GUI to be able to see what is going on?
• Which programming language?

Slide 9: The Raspberry Pi

The Raspberry Pi is a small computer powerful enough to run a full blown Linux operating system: A quad core 1.2 GHz Broadcom 64 bit ARM CPU 1 Gbytes of Ram Ethernet and wireless networks 4 USB2 ports Micro SD connector 40 pin extended GPIO connector with GPIO pins SPI and I2C bus interface Cost ~ 80-100 US $ No ADC

Slide 10: Arduino + WiFi shield

Slide 11: The ideal IoT solution?

ESP8266 or ESP32 processor board ESP8266 specs: WiFi on chip 10 bit ADC on chip 80 kByte RAM 4 Mbyte flash Can run a Micropython interpreter Can be programmed through the Arduino IDE SPI, I2C interfaces 11 GPIO pins Many sensor and actuator boards Can be plugged together without bread board or soldering Cost of processor board: ~ 2.5 US$ ESP32 is even more powerful Cost: ~ 4.5 US$

Slide 12: Communication

MQTT (Message Queuing Telemetry Transport: a publish-subscribe based

Message protocol running of top of TCP.

A processor can subscribe to messages of a certain “topic” and/or it can push its

results on a certain topic

Slide 13: MQTT Demo

Slide 14: Programming language

• Only the data recovered from the communication protocol is seen
• Any programming language will do
• Cayenne/MQTT libraries are available for
  
  
  • C, C++
    
    
  • Python
    
    
  • Java
    
    
  • Java Script

Slide 15: Sensor Readout example: Photo-Resistor and LED

The ADC and GPIO driver classes are already available in MicroPython. This makes readout a child’s game.

Slide 16: Cayenne

• Cayenne supplies the MQTT broker
• It uses a dedicated format for “topic” and “payload”
• We hide these details in a “Cayenne” Python class
• Cayenne supplies widgets for display and control

Slide 17: Cayenne definitions

Slide 18: Publish to Cayenne

Slide 19: Results on Cayenne

Slide 20: ... or the history plot

Slide 21: Do you want to know more?

Unfortunately you missed the workshop on IoT at this conference

But you may have a look at its Twiki server

http://afnog.iotworkshop.africa

… or have a beer with me at the bar!

-- Uli Raich - 2019-05-27

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