1 Introduction

Internet of Things and Raspberry Pi (YouTube) + PowerPoint (PDF)

With Internet of Things (IoT) and Cloud Services Datalogging has reach a new era. The Data are typically stored in the Cloud using traditional SQL databases or more modern systems like NoSQL databases or IoT cloud services. We will use Raspberry Pi or Raspberry Pi Pico. Raspberry Pi is popular to use in different IoT applications. We will primerly use Python, but also MATLAB as programming languages.

Internet of Things Applications typically run on small embedded systems that need to perform under the constraints of limited memory and processing power of small IoT devices. Use of proper Operating Systems for IoT Applications are cruical, meaning Windows 10/11 is not an option. Price is also an important factor in IoT systems, both hardware costs and software costs. Here we will focus on Raspberry Pi and the Linux operation system.

Topics: Internet of Things (IoT), Microcomputers/SBC (Raspberry Pi), Linux, IoT Sensors, SPI/I2C, Python, NoSQL (MongoDB), ThingSpeak (IoT Cloud Service)

You may go through some of the resources (tutorials, videos, examples, exercises, etc.) below or you may start directly on the final delivery. Then you can use these resources if you need help solving some of the different tasks within the delivery.

1.1 Hardware

You will need the following IoT hardware and components (recommended components in bold):

Raspberry Pi (Raspberry Pi 4 is recommended but other versions can also be used). Another alternative is or Raspberry Pi Pico.
Analog Temperature Sensors like TMP36 and/or Thermistor 10K.
ADC (Analog to Digital Converter), e.g., MCP3002 (SPI interface) or similar.
Digital Temperature Sensor with SPI or I2C interface, e.g., TC74 (I2C interface), BME280, DHT20 or AM2320.
Sensors like DS18B20 or DHT11/DHT22 can also be used. These sensors use a so-called 1-Wire interface.
Breadboard, wires, Resistors, LEDs, Push Buttons, etc.

1.2 Software

You will need the following software:

Python
ThingSpeak - IoT Cloud Platform
MATLAB + MATLAB Support Package for Raspberry Pi
MongoDB
Fritzing - Open source software for design of electronics hardware and creating circuit diagrams. You can use Fritzing for designing or documentation of your electrical circuits. Another alternative is Circuit Canvas (recommended!)

2 Raspberry Pi

Raspberry Pi (RP) is a microcomputer and it has an ordinary Operating System (OS). You can connect USB devices, Keyboard, Mouse, Monitors, etc. It has a “hard-drive“ in form of a microSD card. RP has Bluetooth, Wi-Fi, and Ethernet connection. RP has basically all the features an ordinary computer has but in a much smaller package. Raspberry Pi has uptil 8 Gb RAM. RP runs Linux applications, the recommended OS is called Raspberry Pi OS.

Introduction to Raspberry Pi (YouTube) + PowerPoint (PDF)

Raspberry Pi Installation and Remote Access (YouTube) + PowerPoint (PDF)

Raspberry Pi - Overview of Remote Access Alternatives (PDF)

Raspberry Pi Beginner's Guide (PDF)

For making wiring diagrams Circuit Canvas is recommended. Another alternative is Fritzing. These are software tools for design of electronics hardware and creating circuit diagrams. You can use these tools for designing or documentation of your electrical circuits.

Remote Access

Remote Access using Remote Desktop Connection (RDC)

Install XRDP on Raspberry Pi using the Terminal: sudo apt-get install xrdp
Open Remote Desktop Connection (RDC) on your Windows PC. Enter IP address, Username and Password

Do you get a blue screen (empty screen) after login using RDC/RDP on your Window PC? You may need to create another user on your Raspberry Pi. The Pi root user cannot use RDP for some reason?

Create a New User on your Raspberry Pi using the Terminal: sudo adduser <username>
Use that User when logging in through RDC
If the user needs to access GPIO: sudo adduser <username> gpio - similar for SPI, I2C, etc.

Note! An alternative to creating a new user is to use VNC Viewer. You can download the VNC Viewer here. Another alternative is to use TeamViewer.

Raspberry Pi Pico

Raspberry Pi Pico is an alternative to Raspberry Pi. Raspberry Pi Pico is a "downscaled" version of the original Raspberry Pi and is more comparable with Arduino compared to the original Raspberry Pi. You also need to use a downscaled version of Python, called MicroPython.

3 DAQ and IoT Sensors

DAQ (Data Acquisition) and Sensors are needed and used in all IoT applications. DAQ is the process of getting data from the sensors into your software. Here will some popular IoT sensors be presented.

IoT sensors comes in many flavours. Below, some IoT sensors are presented they can be programmed with Python. Below you find more information about the sensors TMP36, Thermistor 10K, TC74, BME280, DHT11/22 and AM2320.

3.1 TMP36

A Temperature sensor like TM36 use a solid-state technique to determine the temperature. They use the fact as temperature increases, the voltage across a diode increases at a known rate.

To use TMP36 with Raspberry Pi, you will need an ADC, e.g., MCP3002 or similar.

3.2 Thermistor 10K

A thermistor is an electronic component that changes resistance to temperature - so-called Resistance Temperature Detectors (RTD). It is often used as a temperature sensor. There is a non-linear relationship between resistance and excitement. To find the temperature we can use the Steinhart-Hart equation.

3.3 TC74

The TC74 acquires and converts temperature information from its onboard solid-state sensor with a resolution of ±1°C. It stores the data in an internal register which is then read through the serial port. The system interface is a slave SMBus/I2C port, through which temperature data can be read at any time.

3.4 BME280

BME280 is a digital Humidity, Pressure and Temperature Sensor from Bosch. The sensor provides both SPI and I2C interfaces. Adafruit, Grove Seeed, SparkFun, etc. have breakout board bords for easy connection to Arduino, Raspberry Pi, etc. The price for these breakout boards are $1-20 depending on where you buy them.

3.5 DHT11/DHT22

The DHTXX sensors are temperature and humidity sensors and they comes in 2 flavours: DHT11 and DHT22. They contains a chip inside that does some analog to digital conversion and spits out a digital signal with the temperature and humidity. Read more.

3.6 DS18B20

DS18B20 is a 1-Wire Digital Temperature Sensor, this means the Sensor only need 1 Pin for Communication (+ one pin for GND and one pin for 5V). Accuracy +/−0.5℃. It has a 9 to 12-bit resolution (Programmable). Temperature range −55°C to +125°C. Price: About $4. Datasheet.

3.7 AM2320

This AM2320 sensor looks a lot like the popular DHT11/DHT22 temperature and humidity sensors, but unlike classic DHT sensors, it has an I2C interface.

4 Digital Sensor Interfaces

Raspberry Pi has only digital I/O pins. In order to use analog sensors likes TMP36 and Thermistor 10K we typicaly need to use an external ADC (e.g., MCP3002).

Raspberry Pi has SPI, I2C and 1-Wire interfaces that can be used for communication with digital sensors like TC74, BME280, DHT11/22 and DS18B20 (and many others).

4.1 SPI/I2C

SPI and I2C are digital interface to communicate with different types of electronic components like Sensors, Analog to Digital Converts (ADC), etc. Most IoT devices, including Arduino and Raspberry Pi, support the SPI and I2C interfaces.

Sensor Examples:

Raspberry Pi using SPI and I2C with Python (PDF) - with ADC/TMP36, TC74 and BME280 Examples

Raspberry Pi and AM2320 Temperature and Humidity Sensor with I2C Interface (PDF)

Raspberry Pi and AM2320 - Testing different existing Libraries (PDF)

Using AM2320 Temperature Sensor with CircuitPython (Website)

4.2 1-Wire

1-Wire is similar in concept to I2C, but with lower data rates and longer range. One-wire devices need a pull-up resistor connected to their signal line to be properly read by your board.

Raspberry Pi and CircuitPython (PDF) - with DTH11/DTH22 Examples

Sensor Examples:

Using DS18B20 Temperature Sensor with CircuitPython

Using DHT11/DHT22 Sensor with CircuitPython

5 Python

Python is a fairly old programming language but has become increasingly popular in the age of Internet of Things.

5.1 Raspberry Pi and Python

Raspberry Pi and Python is a powerful combination. Below you find some resources using Python in combination with Raspberry Pi.

Introduction to Raspberry Pi (YouTube) + PowerPoint (PDF)

Raspberry Pi + Python Tutorials:

Raspberry Pi with Python (YouTube) + PowerPoint (PDF)

Raspberry Pi GPIO with Python (PDF) - with LED, PWM, Pushbutton, ADC and ThingSpeak Examples

Raspberry Pi using SPI and I2C with Python (PDF) - with TMP36, MCP3002 ADC (SPI) , TC74 (I2C) and ThingSpeak Examples

Raspberry Pi and CircuitPython (PDF) - with BME280 and DHT11/DHT22 Examples

Installing Python packages on Raspberry Pi

Python is installed by default as a "system-wide" installation as part of the Raspberry Pi OS and by default in the latest version of Raspberry Pi OS you cannot install Python packages in the global Python ("system-wide" installation) environment on Raspberry Pi OS. This is due to security reasons and the fact that you can destroy this environment by installing new packages which can cause other programs on Raspberry Pi OS to no longer work.

You have then several options when installing Python packages on Raspberry Pi:

Alt 1. You can run "sudo apt-get install python3-packagename" from the Terminal in Rasperry Pi OS to still install packages "system-wide".
Alt 2. You can create a new Virtual Python Environment on the Raspberry Pi. This is the recommended alternative as you do not destroy other programs or the system-wide Python environment. This can be done in several ways, but the easiest way is to do it from the graphical environment in Thonny, alternatively from the Terminal.
Alt 3. You can switch off the default setting which allows you to install Python packages "system-wide" in the usual way using pip/Terminal or from Thonny.

Installing Python Packages on Raspberry Pi (YouTube) + PowerPoint (PDF)

6 ThingSpeak IoT Cloud Service

ThingSpeak is an IoT cloud service used to store IoT data. ThingSpeak is an IoT analytics platform service that lets you collect and store sensor data in the cloud and develop Internet of Things applications. The ThingSpeak service also lets you perform online analysis and act on your data. Sensor data can be sent to ThingSpeak from any hardware that can communicate using a REST API. ThingSpeak has a Web Service (REST API) that lets you collect and store sensor data in the cloud and develop Internet of Things applications. In addition, it also has a MQTT API.

ThingSpeak Web Site: https://thingspeak.com

Python Library for ThingSpeak: https://pypi.org/project/thingspeak/

Raspberry Pi GPIO Python Examples (including ThingSpeak Examples) (PDF)

7 MQTT

Message Queueing Telemetry Transport (MQTT) is an IoT protocol MQTT is used in applications with thousands of sensors. MQTT is efficient in terms of bandwidth, battery, and resources. MQTT uses a publish/subscribe model. MQTT has become the defacto IoT communication protocol. This means if you want to work with IoT projects, you will sooner or later need to use this protocol.

MQTT (YouTube) + PowerPoint (PDF)

MQTT with Python (YouTube) + PowerPoint (PDF)

Additional MQTT Resources

MQTT consists of a MQTT Broker, MQTT Publishers and MQTT Subscribers.

Getting started with MQTT

MQTT Basics - Mathworks

MQTT Software:

HiveMQ Cloud - MQTT Broker in the Cloud

MQTT X - MQTT X is an MQTT 5.0 Open-source Desktop Client

MATLAB:

In order to use MQTT with MATLAB you can use the “Industrial Communication Toolbox”. The “Industrial Communication Toolbox” supports the following Protocols: Modbus, OPC, both OPC DA and OPC UA (previously OPC Toolbox) and MQTT. Note! “Industrial Communication Toolbox” is a new Toolbox that is included in “MATLAB R2022a” and newer versions.

MQTT API for MATLAB

Python:

Python Client Web Page

Eclipse Paho MQTT Python Client (GitHub)

MQTT and Python for Beginners - Tutorials

8 MongoDB

MongoDB is a so-called NoSQL Database. MongoDB is one of the most popular NoSQL database systems. NoSQL databases have become very popular and espesially in IoT applications.

Python and MongoDB (YouTube) + PowerPoint (PDF)

MongoDB Cloud and Python (YouTube) + PowerPoint (PDF)

You can download a free MongoDB database at https://www.mongodb.com.

You can also use MongoDB as a cloud service (MongoDB Atlas): https://www.mongodb.com/cloud/atlas.

Tutorial: Python MongoDB - w3schools.com

9 Raspberry Pi and MATLAB

With MATLAB support package for Raspberry Pi, the Raspberry Pi is connected to a computer running MATLAB. Processing is done on the computer with MATLAB.

Raspberry Pi with MATLAB (YouTube) + PowerPoint (PDF)

Raspberry Pi with MATLAB using SPI and I2C (YouTube) + PowerPoint - TC74 (I2C) and TMP36 with ADC MCP3002 (SPI) Examples are presented in the Video/Tutorial.

Additional Resources:

Raspberry Pi Programming with MATLAB and Simulink

MATLAB Support Package for Raspberry Pi

Getting Started with MATLAB Support Package for Raspberry Pi (YouTube)

10 Raspberry Pi and LabVIEW

In order to use LabVIEW in combination with Rasberry Pi, we can use the LabVIEW Hobbyist Toolkit. Here you can learn LabVIEW Fundamentals.

Note! The LabVIEW Hobbyist Toolkit has replaced the LabVIEW LINX Toolkit. Some of the resources below may still use the LINX term. You install the LabVIEW Hobbyist Toolkit using the NI Package Manager (included with LabVIEW).

Resources:

LabVIEW Hobbyist Toolkit and Raspberry Pi (YouTube) + PowerPoint (PDF)

LabVIEW Hobbyist Toolkit and Raspberry Pi - Part 2 (PDF) - PWM and Push Buttons

LabVIEW Hobbyist Toolkit and Raspberry Pi using SPI and I2C (PDF) - TC74 Temperature Sensor

Delivery

Introduction

In this Assignment we will use Raspberry Pi. We will use the Raspberry Pi to read and log temperature data. We will mainly use Python, but also MATLAB.

Tip! Most of the subtasks can be developed using Python on your PC without the need for a Raspberry Pi. When it works properly on your PC, you can try it on your Raspberry Pi. The Thonny Python editor (that are included with Raspberry Pi) can also be installed on your PC.

You should start your work by creating a System sketch. In that way you will get an overview of the system you are going to create. Make System Sketch in PowerPoint (YouTube).

Note! All parts and tasks (requirements) should finally be put together and presented as one final working system. Pretend you make this for a given customer/client.

An example of a use case may be that you want to have temperature (and, e.g., other parameters like air quality, humidity, barometric air pressure) monitoring in multiple rooms inside one or more buildings.

Then you could have one "data logging device" (the Raspberry Pi with sensors in this case) in each room that sends data to a central database (MongoDB in this case) on a server or in the cloud. Here you see an example of such a device.
Normally it is not allowed or recommended to store data directly into the database from these devices due to security reasons, scaling, performance, etc., so in many cases you need to use a protocol like MQTT (and a MQTT Broker) as a middleware between the logging device and the database.
Finally, you want to monitor and analyze data from one or all the rooms in the system. You may want to see plots, statistics, etc. for energy optimization, etc. In our case this will be a Python script.

The following Tasks (requirements given by the customer) should be done as part of the delivery:

Part 1: Raspberry Pi and Python

Install Raspberry Pi OS on your Raspberry PI. Make sure to establish remote access from your PC, in that way you dont need an extra monitor, keyboard and a mouse.
When you are finished setting up the Raspberry Pi, you may want to start creating a simple Python example where you, e.g., turn on/off an external LED mounted on a breadboard. You may use the Thonny Python editor that is part of the Raspberry Pi OS.
Retrive data from Temperature Sensors, e.g., TMP36 (Analog, ADC required) and an I2C/1-Wire Temperature sensor like TC74 (I2C), DHT11/22 (1-Wire) or AM2320 (I2C). Use the Python programming language. You need to test at least 2 different types of sensors. In the rest of the subtasks you can use one of them (the one you prefer).
Make sure to implement a Lowpass Filter to remove noise from the signal
Use a LED for handling Alarms, i.e, turn on a LED when the temperature goes above or below some Alarm limits. You should use a Push Button to acknowledge the Alarm. You should also use PWM to increase/decrease the brightness of the LED to visualize the Alarm state.
The data should be stored in a MongoDB database that is located either on your PC or in the cloud. It is recommended that you first develop this task on your PC. Then, when it works properly you can try it on your Raspberry Pi.
The data should be also be stored in the cloud service ThingSpeak. It is recommended that you first develop this task on your PC. Then, when it works properly you can try it on your Raspberry Pi.
Create a Python script (on your PC) for Data Analysis based on the data stored in MongoDB or ThingSpeak. Here you should typically plot the data, do some basic statistics analyses, e.g., find mean, standard deviation, variance, median, etc. Some kind of Machine Learning?
Give an overview of how Raspberry Pi OS (Linux) handles Security. What have you done (or could have done) to take care of Cyber Security in your system?

In addition to Part 1, choose one of the parts below (where Part 2a is recommended).

Part 2a: MQTT and Python

Normally it is not allowed or recommended to store data directly into the database from logging devices like Raspberry Pi due to security reasons, scaling, performance, etc., so in many cases you need to use a protocol like MQTT (and a MQTT Broker) as a middleware between the logging device and the database.

This part can mostly be developed on your PC. When it works properly on your PC, you can deploy the necessary parts on your Raspberry Pi.

Use HiveMQ Cloud or install a MQTT Broker (on your PC, not Raspberry Pi) like Eclipse Mosquitto or HiveMQ Community Edition. ThingSpeak has also a MQTT Broker that you can use. Lots of other MQTT Brokers do exist.
Make sure everything works by manually Publish some data using the MQTT X (or similar software), then Subscribe to the Topic where the data are published to see if the data has been published correctly. MQTT X is an MQTT 5.0 Open-source MQTT Desktop Client.
Publish (on your Raspberry Pi) your data from the Temperature Sensor(s) to a MQTT Broker using your Raspberry Pi and Python. The most used MQTT Python Library is paho-mqtt, but you can use another library if you prefer.
Subscribe (on your PC) to the data from the MQTT Broker using Python, then you save the data to MongoDB (in the same Python script). This means that you should no longer need to save data directly to MongoDB from your Raspberry Pi, but use MQTT instead. Then a Python script that runs on your computer should subscribe to the data (from the Broker) and then forward/store the data to the MongoDB database.
Give a short overview of the security mechanisms in MQTT.

Part 2b: MATLAB and Raspberry Pi

In this part we wil use Raspberry Pi in combination with MATLAB and the Discuss.

Install the MATLAB Support Package for Raspberry Pi on your Raspberry Pi device. Note! This may require that you overwrite the SD card from Part1, so you may want to take a backup first, or use another SD card.
Retrive data from one or more Temperature Sensors, e.g., TMP36 or I2C/1-Wire sensors like TC74, etc using your Raspberry Pi and MATLAB Support Package for Raspberry Pi. You can also use a Raspberry Pi Camera Module (available in the laboratory) if you like.
The data should be stored in the cloud service ThingSpeak. Make sure to log enough data that can be used for the data analysis part.
Create a MATLAB script (on your PC) for Data Analysis based on the data stored in ThingSpeak. Here you should typically plot the data, do some basic statistics analyses, e.g., find mean, standard deviation, variance, median, etc. Some kind of Machine Learning?

Note! Hi, MathWorks has just released a new version of MATLAB, R2024b, which also has support for the new Raspberry Pi 5.

Part 2c: LabVIEW and Raspberry Pi

In this part we wil use Raspberry Pi in combination with LabVIEW and LabVIEW Hobbyist Toolkit.

Install and use LabVIEW Hobbyist Toolkit with your Raspberry Pi device.
Retrive data from one or more Temperature Sensors, e.g., TMP36 or I2C/1-Wire sensors like TC74, etc using your Raspberry Pi and LabVIEW LINX. Use Lowpass filter.
Use LED(s) and Push Button(s) and create a simple Alarm System. Use also PWM as part of this system.
The data should be stored in the cloud service ThingSpeak or another cloud service, like MongoDB

Additional Information

Online students or Industry students do also have the possibility to present a work related project they are involved in as a replacement for the tasks given above. This work should then involve use of some kind of IoT hardware (Raspberry Pi or Industrial IoT hardware used by the company), data logging, data storage, cloud storage or services and use of an IoT protocol like MQTT. Also, make sure to discuss cyber security related issues in your system. The company related assignment must be approved by the supervisor before the work starts.

Additional Examples (Voluntary)

Feel free to Explore! Make sure to Add Value and Creativity to your Applications! Try to add some extra value and be creative compared to the simplified examples given by me, in that way you learn so much more.

"Explore and Add Value" Examples (Voluntary, if you have some spare time):

If you have chosen Part 2b/c, it is recommended that you explore MQTT (Part 2a) as well. MQTT has become the defacto IoT communication protocol. This means if you want to work with IoT projects, you will sooner or later need to use this protocol.
Perform a Risk Analysis and create a Risk Matrix when it comes to Cyber Secuity issues regarding the system you create.
Extend the Alarm System where you store Alarms in MongoDB or ThingSpeak.
Explore and use MQTT with MATLAB. The "Industrial Communication Toolbox" in MATLAB supports MQTT.
Explore the Raspberry Pi Camera Module (available in the laboratory)
Can you retrieve data/information from ThingSpeak into Raspberry Pi? Like e.g., remotely turn on a LED?