@ -26,11 +26,11 @@ The term 'Internet of Things' was coined by [Kevin Ashton](https://wikipedia.org
> **Sensors** gather information from the world, such as measuring speed, temperature or location.
>
> **Actuators** convert electrical signals into real-world interactions such as triggering a switch, turning on lights, making sounds, or sending control signals to other hardware, for example to turn on a power socket.
> **Actuators** convert electrical signals into real-world interactions such as triggering a switch, turning on lights, making sounds, or sending control signals to other hardware, for example, to turn on a power socket.
IoT as a technology area is more than just devices - it includes cloudbased services that can process the sensor data, or send requests to actuators connected to IoT devices. It also includes devices that don't have or don't need Internet connectivity, often referred to as edge devices. These are devices that can process and respond to sensor data themselves, usually using AI models trained in the cloud.
IoT as a technology area is more than just devices - it includes cloud-based services that can process the sensor data, or send requests to actuators connected to IoT devices. It also includes devices that don't have or don't need Internet connectivity, often referred to as edge devices. These are devices that can process and respond to sensor data themselves, usually using AI models trained in the cloud.
IoT is a fast growing technology field. It is estimated that by the end of 2020, 30 billion IoT devices were deployed and connected to the Internet. Looking to the future, it is estimated that by 2025, IoT devices will be gathering almost 80 zettabytes of data, or 80 trillion gigabytes. That's a lot of data!
IoT is a fast growing technology field. It is estimated that by the end of 2020, 30 billion IoT devices were deployed and connected to the Internet. Looking to the future, it is estimated that by 2025, IoT devices will be gathering almost 80 zettabytes of data or 80 trillion gigabytes. That's a lot of data!
@ -40,7 +40,7 @@ This data is the key to IoT's success. To be a successful IoT developer, you nee
## IoT devices
The **T** in IoT stands for **Things** - devices that interact with the physical world around them either by gathering data from sensors, or providing real-world interactions via actuators.
The **T** in IoT stands for **Things** - devices that interact with the physical world around them either by gathering data from sensors or providing real-world interactions via actuators.
Devices for production or commercial use, such as consumer fitness trackers, or industrial machine controllers, are usually custom-made. They use custom circuit boards, maybe even custom processors, designed to meet the needs of a particular task, whether that's being small enough to fit on a wrist, or rugged enough to work in a high temperature, high stress or high vibration factory environment.
@ -48,7 +48,7 @@ As a developer either learning about IoT or creating a device prototype, you'll
These developer kits usually fall into two categories - microcontrollers and single-board computers. These will be introduced here, and we'll go into more detail in the next lesson.
> 💁 Your phone can also be considered to be a general-purpose IoT device, with sensors and actuators builtin, with different apps using the sensors and actuators in different ways with different cloud services. You can even find some IoT tutorials that use a phone app as an IoT device.
> 💁 Your phone can also be considered to be a general-purpose IoT device, with sensors and actuators built-in, with different apps using the sensors and actuators in different ways with different cloud services. You can even find some IoT tutorials that use a phone app as an IoT device.
### Microcontrollers
@ -68,7 +68,7 @@ Microcontrollers are typically low cost computing devices, with average prices f
Microcontrollers are designed to be programmed to do a limited number of very specific tasks, rather than being general-purpose computers like PCs or Macs. Except for very specific scenarios, you can't connect a monitor, keyboard and mouse and use them for general purpose tasks.
Microcontroller developer kits usually come with additional sensors and actuators on board. Most boards will have one or more LEDs you can program, along with other devices such as standard plugs for adding more sensors or actuators using various manufacturers' ecosystems, or built in sensors (usually the most popular ones such as temperature sensors). Some microcontrollers have builtin wireless connectivity such as Bluetooth or WiFi, or have additional microcontrollers on the board to add this connectivity.
Microcontroller developer kits usually come with additional sensors and actuators on board. Most boards will have one or more LEDs you can program, along with other devices such as standard plugs for adding more sensors or actuators using various manufacturers' ecosystems or built-in sensors (usually the most popular ones such as temperature sensors). Some microcontrollers have built-in wireless connectivity such as Bluetooth or WiFi or have additional microcontrollers on the board to add this connectivity.
> 💁 Microcontrollers are usually programmed in C/C++.
@ -90,7 +90,7 @@ Single-board computers are fully-featured computers, so can be programmed in any
### Hardware choices for the rest of the lessons
All the subsequent lessons include assignments using an IoT device to interact with the physical world, and communicate with the cloud. Each lesson supports 3 device choices - Arduino (using a Seeed Studios Wio Terminal), or a single-board computer, either a physical device (a Raspberry Pi 4), or a virtual single-board computer running on your PC or Mac.
All the subsequent lessons include assignments using an IoT device to interact with the physical world and communicate with the cloud. Each lesson supports 3 device choices - Arduino (using a Seeed Studios Wio Terminal), or a single-board computer, either a physical device (a Raspberry Pi 4) or a virtual single-board computer running on your PC or Mac.
You can read about the hardware needed to complete all the assignments in the [hardware guide](../../../hardware.md).
@ -148,15 +148,15 @@ IoT covers a huge range of use cases, across a few broad groups:
### Consumer IoT
Consumer IoT refers to IoT devices that consumers will buy and use around the home. Some of these devices are incredibly useful, such as smart speakers, smart heating systems and robotic vacuum cleaners. Others are questionable in their usefulness, such as voicecontrolled taps that then mean you cannot turn them off as the voice control cannot hear you over the sound of running water.
Consumer IoT refers to IoT devices that consumers will buy and use around the home. Some of these devices are incredibly useful, such as smart speakers, smart heating systems and robotic vacuum cleaners. Others are questionable in their usefulness, such as voice-controlled taps that then mean you cannot turn them off as the voice control cannot hear you over the sound of running water.
Consumer IoT devices are empowering people to achieve more in their surroundings, especially the 1 billion who have a disability. Robotic vacuum cleaners can provide clean floors to people with mobility issues who cannot vacuum themselves, voicecontrolled ovens allow people with limited vision or motor control to heat their ovens with only their voice, health monitors can allow patients to monitor chronic conditions themselves with more regular and more detailed updates on their conditions. These devices are becoming so ubiquitous that even young children are using them as part of their daily lives, for example students doing virtual schooling during the COVID pandemic setting timers on smart home devices to track their schoolwork or alarms to remind them of upcoming class meetings.
Consumer IoT devices are empowering people to achieve more in their surroundings, especially the 1 billion who have a disability. Robotic vacuum cleaners can provide clean floors to people with mobility issues who cannot vacuum themselves, voice-controlled ovens allow people with limited vision or motor control to heat their ovens with only their voice, health monitors can allow patients to monitor chronic conditions themselves with more regular and more detailed updates on their conditions. These devices are becoming so ubiquitous that even young children are using them as part of their daily lives, for example, students doing virtual schooling during the COVID pandemic setting timers on smart home devices to track their schoolwork or alarms to remind them of upcoming class meetings.
✅ What consumer IoT devices do you have on your person or in your home?
### Commercial IoT
Commercial IoT covers the use of IoT in the workplace. In an office setting there may be occupancy sensors and motion detectors to manage lighting and heating to only keep the lights and heat off when not needed, reducing cost and carbon emissions. In a factory, IoT devices can monitor for safety hazards such as workers not wearing hard hats or noise that has reached dangerous levels. In retail, IoT devices can measure the temperature of cold storage, alerting the shop owner if a fridge or freezer is outside the required temperature range, or they can monitor items on shelves to direct employees to refill produce that has been sold. The transport industry is relying more and more on IoT to monitor vehicle locations, track on-road mileage for road user charging, track driver hours and break compliance, or notify staff when a vehicle is approaching a depot to prepare for loading or unloading.
Commercial IoT covers the use of IoT in the workplace. In an office setting, there may be occupancy sensors and motion detectors to manage lighting and heating to only keep the lights and heat off when not needed, reducing cost and carbon emissions. In a factory, IoT devices can monitor for safety hazards such as workers not wearing hard hats or noise that has reached dangerous levels. In retail, IoT devices can measure the temperature of cold storage, alerting the shop owner if a fridge or freezer is outside the required temperature range, or they can monitor items on shelves to direct employees to refill produce that has been sold. The transport industry is relying more and more on IoT to monitor vehicle locations, track on-road mileage for road user charging, track driver hours and break compliance, or notify staff when a vehicle is approaching a depot to prepare for loading or unloading.
✅ What commercial IoT devices do you have in your school or workplace?
@ -166,7 +166,7 @@ Industrial IoT, or IIoT, is the use of IoT devices to control and manage machine
Factories use IoT devices in many different ways. Machinery can be monitored with multiple sensors to track things like temperature, vibration and rotation speed. This data can then be monitored to allow the machine to be stopped if it goes outside of certain tolerances - it runs too hot and gets shut down for example. This data can also be gathered and analyzed over time to do predictive maintenance, where AI models will look at the data leading up to a failure, and use that to predict other failures before they happen.
Digital agriculture is important if the planet is to feed the growing population, especially for the 2 billion people in 500 million households that survive on [subsistence farming](https://wikipedia.org/wiki/Subsistence_agriculture). Digital agriculture can range from a few single digit dollar sensors, to massive commercial setups. A farmer can start by monitoring temperatures and using [growing degree days](https://wikipedia.org/wiki/Growing_degree-day) to predict when a crop will be ready for harvest. They can connect soil moisture monitoring to automated watering systems to give their plants as much water as is needed, but no more to ensure their crops don't dry out without wasting water. Farmers are even taking it further and using drones, satellite data and AI to monitor crop growth, disease and soil quality over huge areas of farmland.
Digital agriculture is important if the planet is to feed the growing population, especially for the 2 billion people in 500 million households that survive on [subsistence farming](https://wikipedia.org/wiki/Subsistence_agriculture). Digital agriculture can range from a few single digit dollar sensors to massive commercial setups. A farmer can start by monitoring temperatures and using [growing degree days](https://wikipedia.org/wiki/Growing_degree-day) to predict when a crop will be ready for harvest. They can connect soil moisture monitoring to automated watering systems to give their plants as much water as is needed, but no more to ensure their crops don't dry out without wasting water. Farmers are even taking it further and using drones, satellite data and AI to monitor crop growth, disease and soil quality over huge areas of farmland.
✅ What other IoT devices could help farmers?
@ -191,7 +191,7 @@ You'd be amazed by just how many IoT devices you have around you. I'm writing th
* Video doorbell and security cameras
* Smart thermostat with multiple smart room sensors
* Garage door opener
* Home entertainment systems and voicecontrolled TVs
* Home entertainment systems and voice-controlled TVs
@ -20,7 +20,7 @@ Install the Grove base hat on your Pi and configure the Pi
1. Decide how you want to program you Pi, and head to the relevant section below:
1. Decide how you want to program your Pi, and head to the relevant section below:
* [Work directly on your Pi](#work-directly-on-your-pi)
* [Remote access to code the Pi](#remote-access-to-code-the-pi)
@ -53,7 +53,7 @@ To program the Pi using the Grove sensors and actuators, you will need to instal
One of the powerful features of Python is the ability to install [pip packages](https://pypi.org) - these are packages of code written by other people and published to the Internet. You can install a pip package onto your computer with one command, then use that package in your code. This Grove install script will install the pip packages you will use to work with the Grove hardware from Python.
1. Reboot the Pi either using the menu, or running the following command in the Terminal:
1. Reboot the Pi either using the menu or running the following command in the Terminal:
```sh
sudo reboot
@ -93,7 +93,7 @@ Set up the headless Pi OS.
> 💁 Raspberry Pi OS Lite is a version of Raspberry Pi OS that doesn't have the desktop UI, or UI based tools. These aren't needed for a headless Pi, and makes the install smaller and boot up time faster.
> 💁 Raspberry Pi OS Lite is a version of Raspberry Pi OS that doesn't have the desktop UI or UI based tools. These aren't needed for a headless Pi and makes the install smaller and boot up time faster.
1. Select the **CHOOSE STORAGE** button, then select your SD card
@ -109,7 +109,7 @@ Set up the headless Pi OS.
1. Select the **WRITE** button to write the OS to the SD card. If you are using macOS, you will be asked to enter your password as the underlying tool that writes disk images needs privileged access.
The OS will be written to the SD card, and once compete the card will be ejected by the OS, and you will be notified. Remove the SD card from your computer, insert it into the Pi and power up the Pi.
The OS will be written to the SD card, and once complete the card will be ejected by the OS, and you will be notified. Remove the SD card from your computer, insert it into the Pi and power up the Pi.
#### Connect to the Pi
@ -139,7 +139,7 @@ Remotely access the Pi.
1. If you are using Windows, the easiest way to enable ZeroConf is to install [Bonjour Print Services for Windows](http://support.apple.com/kb/DL999). You can also install [iTunes for Windows](https://www.apple.com/itunes/download/) to get a newer version of the utility (which is not available standalone).
> 💁 If you cannot connect using `raspberrypi.local`, then you can use the IP address of your Pi. Refer to the [Raspberry Pi IP address documentation](https://www.raspberrypi.org/documentation/remote-access/ip-address.md) for instructions of a number of ways to get the IP address.
> 💁 If you cannot connect using `raspberrypi.local`, then you can use the IP address of your Pi. Refer to the [Raspberry Pi IP address documentation](https://www.raspberrypi.org/documentation/remote-access/ip-address.md) for instructions on a number of ways to get the IP address.
1. Enter the password you set in the Raspberry Pi Imager Advanced Options
@ -157,7 +157,7 @@ Configure the installed Pi software and install the Grove libraries.
@ -82,7 +82,7 @@ Configure a Python virtual environment and install the pip packages for CounterF
> 💁 Your Python version may be different - as long as it's version 3.6 or higher you are good. If not, delete this folder, install a newer version of Python and try again.
1. Run the following commands to install the pip packages for CounterFit. These packages include the main CounterFit app as well as shims for Grove hardware. These shims allow you to write code as if you were programming using physical sensors and actuators from the Grove ecosystem, but connected to virtual IoT devices.
1. Run the following commands to install the pip packages for CounterFit. These packages include the main CounterFit app as well as shims for Grove hardware. These shims allow you to write code as if you were programming using physical sensors and actuators from the Grove ecosystem but connected to virtual IoT devices.
```sh
pip install CounterFit
@ -120,7 +120,7 @@ Create a Python application to print `"Hello World"` to the console.
code .
```
> 💁 If your terminal returns `command not found` on macOS it means VS Code has not been added to your PATH. You can add VS Code to yout PATH by following the instructions in the [Launching from the command line section of the VS Code documentation](https://code.visualstudio.com/docs/setup/mac?WT.mc_id=academic-17441-jabenn#_launching-from-the-command-line) and run the command afterwards. VS Code is installed to your PATH by default on Windows and Linux.
> 💁 If your terminal returns `command not found` on macOS it means VS Code has not been added to your PATH. You can add VS Code to your PATH by following the instructions in the [Launching from the command line section of the VS Code documentation](https://code.visualstudio.com/docs/setup/mac?WT.mc_id=academic-17441-jabenn#_launching-from-the-command-line) and run the command afterwards. VS Code is installed to your PATH by default on Windows and Linux.
1. When VS Code launches, it will activate the Python virtual environment. You will see this in the bottom status bar:
The [Wio Terminal from Seeed Studios](https://www.seeedstudio.com/Wio-Terminal-p-4509.html) is an Arduino-compatible microcontroller, with WiFi and some sensors and actuators builtin, as well as ports to add more sensors and actuators, using a hardware ecosystem called [Grove](https://www.seeedstudio.com/category/Grove-c-1003.html).
The [Wio Terminal from Seeed Studios](https://www.seeedstudio.com/Wio-Terminal-p-4509.html) is an Arduino-compatible microcontroller, with WiFi and some sensors and actuators built-in, as well as ports to add more sensors and actuators, using a hardware ecosystem called [Grove](https://www.seeedstudio.com/category/Grove-c-1003.html).
@ -18,7 +18,7 @@ Install the required software and update the firmware.
1. Install the VS Code PlatformIO extension. This is an extension for VS Code that supports programming microcontrollers in C/C++. Refer to the [PlatformIO extension documentation](https://marketplace.visualstudio.com/items?itemName=platformio.platformio-ide&WT.mc_id=academic-17441-jabenn) for instructions on installing this extension in VS Code. This extension depends on the Microsoft C/C++ extension to work with C and C++ code, and the C/C++ extension is installed automatically when you install PlatformIO.
1. Connect your Wio Terminal to your computer. The Wio Terminal has a USB-C port on the bottom, and this needs to be connected to a USB port on your computer. The Wio Terminal comes with a USB-C to USB-A cable, but if your computer only has USB-C ports then you will either need a USB-C cable, or a USB-A to USB-C adapter.
1. Connect your Wio Terminal to your computer. The Wio Terminal has a USB-C port on the bottom, and this needs to be connected to a USB port on your computer. The Wio Terminal comes with a USB-C to USB-A cable, but if your computer only has USB-C ports then you will either need a USB-C cable or a USB-A to USB-C adapter.
1. Follow the instructions in the [Wio Terminal Wiki WiFi Overview documentation](https://wiki.seeedstudio.com/Wio-Terminal-Network-Overview/) to set up your Wio Terminal and update the firmware.
@ -75,10 +75,10 @@ The VS Code explorer will show a number of files and folders created by the Plat
#### Folders
* `.pio` - this folder contains temporary data needed by PlatformIO such as libraries or compiled code. It is recreated automatically if deleted, and you don't need to add this to source code control if you are sharing your project on sites such as GitHub.
* `.vscode` - this folder contains configuration used by PlatformIO and VS Code. It is recreated automatically if deleted, and you don't need to add this to source code control if you are sharing your project on sites such as GitHub.
* `.vscode` - this folder contains the configuration used by PlatformIO and VS Code. It is recreated automatically if deleted, and you don't need to add this to source code control if you are sharing your project on sites such as GitHub.
* `include` - this folder is for external header files needed when adding additional libraries to your code. You won't be using this folder in any of these lessons.
* `lib` - this folder is for external libraries that you want to call from your code. You won't be using this folder in any of these lessons.
* `src` - this folder contains the main source code for your application. Initially it will contain a single file - `main.cpp`.
* `src` - this folder contains the main source code for your application. Initially, it will contain a single file - `main.cpp`.
* `test` - this folder is where you would put any unit tests for your code
#### Files
@ -99,7 +99,7 @@ The VS Code explorer will show a number of files and folders created by the Plat
When the device starts up, the Arduino framework will run the `setup` function once, then run the `loop` function repeatedly until the device is turned off.
* `.gitignore` - this file lists the files an directories to be ignored when adding your code to git source code control, such as uploading to a repository on GitHub.
* `.gitignore` - this file lists the files and directories to be ignored when adding your code to git source code control, such as uploading to a repository on GitHub.
* `platformio.ini` - this file contains configuration for your device and app. If you open this file, you will see the following:
@ -150,9 +150,9 @@ Write the Hello World app.
}
```
The `setup` function initializes a connection to the serial port - in this case the USB port that is used to connect the Wio Terminal to your computer. The parameter `9600` is the [baud rate](https://wikipedia.org/wiki/Symbol_rate) (also known as Symbol rate), or speed that data will be sent over the serial port in bits per second. This setting means 9,600 bits (0s and 1s) of data are sent each second. It then waits for the serial port to be ready.
The `setup` function initializes a connection to the serial port - in this case, the USB port that is used to connect the Wio Terminal to your computer. The parameter `9600` is the [baud rate](https://wikipedia.org/wiki/Symbol_rate) (also known as Symbol rate), or speed that data will be sent over the serial port in bits per second. This setting means 9,600 bits (0s and 1s) of data are sent each second. It then waits for the serial port to be ready.
The `loop` function sends the line `Hello World!` to the serial port, so the characters of `Hello World!` along with a new line character. It then sleeps for 5,000 milliseconds, or 5 seconds. After the `loop` ends, it is run again, and again, and so on all the time the microcontroller is powered on.
The `loop` function sends the line `Hello World!` to the serial port, so the characters of `Hello World!` along with a new line character. It then sleeps for 5,000 milliseconds or 5 seconds. After the `loop` ends, it is run again, and again, and so on all the time the microcontroller is powered on.
1. Build and upload the code to the Wio Terminal
@ -164,7 +164,7 @@ Write the Hello World app.
PlatformIO will automatically build the code if needed before uploading.
1. The code will be compiled, and uploaded to the Wio Terminal
1. The code will be compiled and uploaded to the Wio Terminal
> 💁 If you are using macOS you will see a notification about a *DISK NOT EJECTED PROPERLY*. This is because the Wio Terminal gets mounted as a drive as part of the flashing process, and it is disconnected when the compiled code is written to the device. You can ignore this notification.
The two components of an IoT application are the *Internet* and the *thing*. Lets look at these two components in a bit more detail.
The two components of an IoT application are the *Internet* and the *thing*. Let's look at these two components in a bit more detail.
### The Thing
@ -28,9 +28,9 @@ The two components of an IoT application are the *Internet* and the *thing*. Let
***Raspberry Pi 4. Michael Henzler / [Wikimedia Commons](https://commons.wikimedia.org/wiki/Main_Page) / [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)***
The **Thing** part of IoT refers to a device that can interact with the physical world. These devices are usually small, low-priced computers, running at low speeds and using low power - for example simple microcontrollers with kilobytes of RAM (as opposed to gigabytes in a PC) running at only a few hundred megahertz (as opposed to gigahertz in a PC), but consuming sometimes so little power they can run for weeks, months or even years on batteries.
The **Thing** part of IoT refers to a device that can interact with the physical world. These devices are usually small, low-priced computers, running at low speeds and using low power - for example, simple microcontrollers with kilobytes of RAM (as opposed to gigabytes in a PC) running at only a few hundred megahertz (as opposed to gigahertz in a PC), but consuming sometimes so little power they can run for weeks, months or even years on batteries.
These devices interact with the physical world, either by using sensors to gather data from their surroundings, or by controlling outputs or actuators to make physical changes. The typical example of this is a smart thermostat - a device that has a temperature sensor, a means to set a desired temperature such as a dial or touchscreen, and a connection to a heating or cooling system that can be turned on when the temperature detected is outside the desired range. The temperature sensor detects that the room is too cold and an actuator turns the heating on.
These devices interact with the physical world, either by using sensors to gather data from their surroundings or by controlling outputs or actuators to make physical changes. The typical example of this is a smart thermostat - a device that has a temperature sensor, a means to set a desired temperature such as a dial or touchscreen, and a connection to a heating or cooling system that can be turned on when the temperature detected is outside the desired range. The temperature sensor detects that the room is too cold and an actuator turns the heating on.
@ -46,7 +46,7 @@ The **Internet** side of an IoT application consists of applications that the Io
One typical setup would be having some kind of cloud service that the IoT device connects to, and this cloud service handles things like security, as well as receiving messages from the IoT device, and sending messages back to the device. This cloud service would then connect to other applications that can process or store sensor data, or use the sensor data with data from other systems to make decisions.
Devices also don't always connect directly to the Internet themselves via WiFi or wired connections. Some devices use mesh networking to talk to each other over technologies such as bluetooth, connecting via a hub device that has the Internet connection.
Devices also don't always connect directly to the Internet themselves via WiFi or wired connections. Some devices use mesh networking to talk to each other over technologies such as Bluetooth, connecting via a hub device that has an Internet connection.
With the example of a smart thermostat, the thermostat would connect using home WiFi to a cloud service running in the cloud. It would send the temperature data to this cloud service, and from there it will be written to a database of some kind allowing the homeowner to check the current and past temperatures using a phone app. Another service in the cloud would know what temperature the homeowner wants, and send messages back to the IoT device via the cloud service to tell the heating system to turn on or off.
@ -54,7 +54,7 @@ With the example of a smart thermostat, the thermostat would connect using home
***An Internet connected thermostat with mobile app control. Temperature by Vectors Market / Microcontroller by Template / dial by Jamie Dickinson / heater by Pascal Heß / mobile phone by Alice-vector / Cloud by Debi Alpa Nugraha - all from the [Noun Project](https://thenounproject.com)***
An even smarter version could use AI in the cloud with data from other sensors connected to other IoT devices such as occupancy sensors that detect what rooms are in use, as well as data such as weather and even your calendar, to make decisions on how to set the temperature in a smart fashion. For example it could turn your heating off if it reads from your calendar you are on vacation, or turn off the heating on a room by room basis depending on what rooms you use, learning from the data to be more and more accurate over time.
An even smarter version could use AI in the cloud with data from other sensors connected to other IoT devices such as occupancy sensors that detect what rooms are in use, as well as data such as weather and even your calendar, to make decisions on how to set the temperature in a smart fashion. For example, it could turn your heating off if it reads from your calendar you are on vacation, or turn off the heating on a room by room basis depending on what rooms you use, learning from the data to be more and more accurate over time.
@ -64,7 +64,7 @@ An even smarter version could use AI in the cloud with data from other sensors c
### IoT on the Edge
Although the I in IoT stands for Internet, these devices don't have to connect to the Internet. In some cases devices can connect to 'edge' devices - gateway devices that run on your local network meaning you can process data without making a call over the Internet. This can be faster when you have a lot of data or a slow Internet connection, it allows you to run offline where Internet connectivity is not possible such as on a ship or in a disaster area when responding to a humanitarian crisis, and allows you to keep data private. Some devices will contain processing code created using cloud tools, and run this locally to gather and respond to data without using an Internet connection to make a decision.
Although the I in IoT stands for Internet, these devices don't have to connect to the Internet. In some cases, devices can connect to 'edge' devices - gateway devices that run on your local network meaning you can process data without making a call over the Internet. This can be faster when you have a lot of data or a slow Internet connection, it allows you to run offline where Internet connectivity is not possible such as on a ship or in a disaster area when responding to a humanitarian crisis, and allows you to keep data private. Some devices will contain processing code created using cloud tools and run this locally to gather and respond to data without using an Internet connection to make a decision.
One example of this is a smart home device such as an Apple HomePod, Amazon Alexa, or Google Home, which will listen to your voice using AI models trained in the cloud, and will 'wake up' when a certain word or phrase is spoken, and only then send your speech to the Internet for processing, keeping everything else you say private.
@ -76,35 +76,35 @@ With any Internet connection, security is an important consideration. There is a
IoT devices connect to a cloud service, and therefore are only as secure as that cloud service - if your cloud service allows any device to connect then malicious data can be sent, or virus attacks can take place. This can have very real world consequences as IoT devices interact and control other devices. For example, the [Stuxnet worm](https://wikipedia.org/wiki/Stuxnet) manipulated valves in centrifuges to damage them. Hackers have also taken advantage of [poor security to access baby monitors](https://www.npr.org/sections/thetwo-way/2018/06/05/617196788/s-c-mom-says-baby-monitor-was-hacked-experts-say-many-devices-are-vulnerable) and other home surveillance devices.
> 💁 Sometimes IoT devices and the edge devices run on network completely isolated from the Internet to keep the data private and secure. This is know as [air-gapping](https://wikipedia.org/wiki/Air_gap_(networking)).
> 💁 Sometimes IoT devices and edge devices run on a network completely isolated from the Internet to keep the data private and secure. This is known as [air-gapping](https://wikipedia.org/wiki/Air_gap_(networking)).
## Deeper dive into microcontrollers
In the last lesson we introduced microcontrollers. Lets now look deeper into them.
In the last lesson, we introduced microcontrollers. Let's now look deeper into them.
### CPU
The CPU is the 'brain' of the microcontroller. It is the processor that runs your code and can send data to and receive data from any connected devices. CPUs can contain one or more cores - essentially one or more CPUs that can work together to run your code.
CPUs rely on a clock to tick many millions or billions of times a second. Each tick, or cycle, synchronizes the actions that the CPU can take. With each tick, the CPU can execute an instruction from a program, such as to retrieve data from an external device, or perform a mathematical calculation. This regular cycle allows for all actions to be completed before the next instructions is processed.
CPUs rely on a clock to tick many millions or billions of times a second. Each tick, or cycle, synchronizes the actions that the CPU can take. With each tick, the CPU can execute an instruction from a program, such as to retrieve data from an external device or perform a mathematical calculation. This regular cycle allows for all actions to be completed before the next instruction is processed.
The faster the clock cycle, the more instructions that can be processed each second, and therefore the faster the CPU. CPU speeds are measured in [Hertz (Hz)](https://wikipedia.org/wiki/Hertz), a standard unit where 1 Hz means one cycle or clock tick per second.
> 🎓 CPU speeds are often given in MHz or GHz. 1MHz is 1 million Hz, 1GHz is 1 billion Hz.
> 💁 CPUs execute programs using the [fetch-decode-execute cycle](https://wikipedia.org/wiki/Instruction_cycle). Every clock tick the CPU will fetch the next instruction from memory, decode it, then execute it such as using an arithmetic logic unit (ALU) to add 2 numbers. Some executions will take multiple ticks to run, so the next cycle will run at the next tick after the instruction has completed.
> 💁 CPUs execute programs using the [fetch-decode-execute cycle](https://wikipedia.org/wiki/Instruction_cycle). For every clock tick, the CPU will fetch the next instruction from memory, decode it, then execute it such as using an arithmetic logic unit (ALU) to add 2 numbers. Some executions will take multiple ticks to run, so the next cycle will run at the next tick after the instruction has completed.
***CPU by Icon Lauk / ram by Atif Arshad - all from the [Noun Project](https://thenounproject.com)***
Microcontrollers have much lower clock speeds than desktop or laptop computers, or even most smartphones. The Wio Terminal for example has a CPU that runs at 120MHz, or 120,000,000 cycles per second.
Microcontrollers have much lower clock speeds than desktop or laptop computers, or even most smartphones. The Wio Terminal for example has a CPU that runs at 120MHz or 120,000,000 cycles per second.
✅ An average PC or Mac has a CPU with multiple cores running at multiple GigaHertz, meaning the clock ticks billions of times a second. Research the clock speed of your computer and see how many times faster it is than the Wio terminal.
Each clock cycle draws power and generates heat. The faster the ticks, the more power consumed and more heat generated. PC's have heat sinks and fans to remove heat, without which they would overheat and shut down within seconds. Microcontrollers often have neither as they run much cooler and therefore much slower. PC's run off mains power or large batteries for a few hours, microcontrollers can run for days, months, or even years off small batteries. Microcontrollers can also have cores that run at different speeds, switching to slower low power cores when the demand on the CPU is low to reduce power consumption.
> 💁 Some PCs and Macs are adopting the same mix of fast high power cores and slower low power cores, switching to save battery. For example the M1 chip in the latest Apple laptops can switch between 4 performance cores and 4 efficiency cores to optimize battery life or speed depending on the task being run.
> 💁 Some PCs and Macs are adopting the same mix of fast high power cores and slower low power cores, switching to save battery. For example, the M1 chip in the latest Apple laptops can switch between 4 performance cores and 4 efficiency cores to optimize battery life or speed depending on the task being run.
✅ Do a little research: Read up on CPUs on the [Wikipedia CPU article](https://wikipedia.org/wiki/Central_processing_unit)
@ -124,7 +124,7 @@ RAM is the memory used by the program to run, containing variables allocated by
> 🎓 Program memory stores your code and stays when there is no power.
> 🎓 RAM is used to run your program, and is reset when there is no power
> 🎓 RAM is used to run your program and is reset when there is no power
Like with the CPU, the memory on a microcontroller is orders of magnitude smaller than a PC or Mac. A typical PC might have 8 Gigabytes (GB) of RAM, or 8,000,0000,000 bytes, with each byte enough space to store a single letter or a number from 0-255. A microcontroller would have only Kilobytes (KB) of RAM, with a kilobyte being 1,000 bytes. The Wio terminal mentioned above has 192KB of RAM, or 192,000 bytes - more than 40,000 times less than an average PC!
@ -180,19 +180,19 @@ You can program microcontrollers using an OS - often referred to as a real-time
[Arduino](https://www.arduino.cc) is probably the most popular microcontroller framework, especially among students, hobbyists and makers. Arduino is an open source electronics platform combining software and hardware. You can buy Arduino compatible boards from Arduino themselves, or from other manufacturers, then code using the Arduino framework.
[Arduino](https://www.arduino.cc) is probably the most popular microcontroller framework, especially among students, hobbyists and makers. Arduino is an open source electronics platform combining software and hardware. You can buy Arduino compatible boards from Arduino themselves or from other manufacturers, then code using the Arduino framework.
Arduino boards are coded in C or C++. Using C/C++ allows your code to be compiled very small and run fast, something needed on a constrained device such as a microcontroller. The core of an Arduino application is referred to as a sketch, and is C/C++ code with 2 functions - `setup` and `loop`. When the board starts up, the Arduino framework code will run the `setup` function once, then it will run the `loop` function again and again, running it continuously until the power is powered off.
Arduino boards are coded in C or C++. Using C/C++ allows your code to be compiled very small and run fast, something needed on a constrained device such as a microcontroller. The core of an Arduino application is referred to as a sketch and is C/C++ code with 2 functions - `setup` and `loop`. When the board starts up, the Arduino framework code will run the `setup` function once, then it will run the `loop` function again and again, running it continuously until the power is powered off.
You would write your setup code in the `setup` function, such as connecting to WiFi and cloud services or initializing pins for input and output. Your loop code would then contain processing code, such as reading from a sensor and sending the value to the cloud. You would normally include a delay in each loop, for example if you only want sensor data to be sent every 10 seconds you would add a delay of 10 seconds at the end of the loop so the microcontroller can sleep, saving power, then run the loop again when needed 10 seconds later.
You would write your setup code in the `setup` function, such as connecting to WiFi and cloud services or initializing pins for input and output. Your loop code would then contain processing code, such as reading from a sensor and sending the value to the cloud. You would normally include a delay in each loop, for example, if you only want sensor data to be sent every 10 seconds you would add a delay of 10 seconds at the end of the loop so the microcontroller can sleep, saving power, then run the loop again when needed 10 seconds later.
✅ This program architecture is know as an *event loop* or *message loop*. Many applications use this under the hood, and is the standard for most desktop applications that run on OSes like Windows, macOS or Linux. The `loop` listens for messages from user interface components such as buttons, or devices like the keyboard, and responds to them. You can read more in this [article on the event loop](https://wikipedia.org/wiki/Event_loop).
✅ This program architecture is known as an *event loop* or *message loop*. Many applications use this under the hood and is the standard for most desktop applications that run on OSes like Windows, macOS or Linux. The `loop` listens for messages from user interface components such as buttons, or devices like the keyboard, and responds to them. You can read more in this [article on the event loop](https://wikipedia.org/wiki/Event_loop).
Arduino provides standard libraries for interacting with microcontrollers and the I/O pins, with different implementations under the hood to run on different microcontrollers. For example, the [`delay` function](https://www.arduino.cc/reference/en/language/functions/time/delay/) will pause the program for a given period of time, the [`digitalRead` function](https://www.arduino.cc/reference/en/language/functions/digital-io/digitalread/) will read a value of `HIGH` or `LOW` from the given pin, regardless of which board the code is run on. These standard libraries mean that Arduino code written for one board can be recompiled for any other Arduino board and will run, assuming that the pins are the same and the boards support the same features.
There is a large ecosystem of third-party Arduino libraries that allow you to add extra features to your Arduino projects, such as using sensors and actuators, or connecting to cloud IoT services.
There is a large ecosystem of third-party Arduino libraries that allow you to add extra features to your Arduino projects, such as using sensors and actuators or connecting to cloud IoT services.
##### Task
@ -202,13 +202,13 @@ If you are using a Wio Terminal for these lessons, re-read the code you wrote in
## Deeper dive into single-board computers
In the last lesson we introduced single-board computers. Lets now look deeper into them.
In the last lesson, we introduced single-board computers. Let's now look deeper into them.
### Raspberry Pi
The [Raspberry Pi Foundation](https://www.raspberrypi.org) is a charity from the UK founded in 2009 to promote the study of computer science, especially at school level. As part of this mission they developed a single-board computer, called the Raspberry Pi. Raspberry Pis are currently available in 3 variants - a full size version, the smaller Pi Zero, and an compute module that can be built into your final IoT device.
The [Raspberry Pi Foundation](https://www.raspberrypi.org) is a charity from the UK founded in 2009 to promote the study of computer science, especially at school level. As part of this mission, they developed a single-board computer, called the Raspberry Pi. Raspberry Pis are currently available in 3 variants - a full size version, the smaller Pi Zero, and a compute module that can be built into your final IoT device.
@ -27,12 +27,12 @@ Sensors are hardware devices that sense the physical world - that is they measur
Some common sensors include:
* Temperature sensors - these sense the air temperature, or the temperature of what they are immersed in. For hobbyists and developer, these are often combined with air pressure and humidity in a single sensor.
* Temperature sensors - these sense the air temperature or the temperature of what they are immersed in. For hobbyists and developer, these are often combined with air pressure and humidity in a single sensor.
* Buttons - they sense when they have been pressed.
* Light sensors - these detect light levels, and can be for specific colors, UV light, IR light, or general visible light.
* Light sensors - these detect light levels and can be for specific colors, UV light, IR light, or general visible light.
* Cameras - these sense a visual representation of the world by taking a photograph or streaming video.
* Accelerometers - these sense movement in multiple directions.
* Microphones - these sense sound, either general sound levels, or directional sound.
* Microphones - these sense sound, either general sound levels or directional sound.
✅ Do some research. What sensors does your phone have?
@ -54,7 +54,7 @@ Sensors are either analog or digital.
Some of the most basic sensors are analog sensors. These sensors receive a voltage from the IoT device, the sensor components adjust this voltage, and the voltage that is returned from the sensor is measured to give the sensor value.
> 🎓 Voltage is a measure of how much push there is to move electricity from one place to another, such as from a positive terminal of a battery to the negative terminal. For example, a standard AA battery is 1.5V (V is the symbol for volts), and can push electricity with the force of 1.5V from it's positive terminal to its negative terminal. Different electrical hardware requires different voltages to work, for example an LED can light with between 2-3V, but a 100W filament lightbulb would need 240V. You can read more about voltage on the [Voltage page on Wikipedia](https://wikipedia.org/wiki/Voltage).
> 🎓 Voltage is a measure of how much push there is to move electricity from one place to another, such as from a positive terminal of a battery to the negative terminal. For example, a standard AA battery is 1.5V (V is the symbol for volts) and can push electricity with the force of 1.5V from it's positive terminal to its negative terminal. Different electrical hardware requires different voltages to work, for example, an LED can light with between 2-3V, but a 100W filament lightbulb would need 240V. You can read more about voltage on the [Voltage page on Wikipedia](https://wikipedia.org/wiki/Voltage).
One example of this is a potentiometer. This is a dial that you can rotate between two positions and the sensor measures the rotation.
@ -66,7 +66,7 @@ The IoT device will send an electrical signal to the potentiometer at a voltage,
> 🎓 This is an oversimplification, and you can read more on potentiometers and variable resistors on the [potentiometer Wikipedia page](https://wikipedia.org/wiki/Potentiometer).
The voltage that comes out the sensor is then read by the IoT device, and the device can respond to it. Depending on the sensor, this voltage can be an arbitrary value, or can map to a standard unit. For example an analog temperature sensor based on a [thermistor](https://wikipedia.org/wiki/Thermistor) changes it's resistance depending on the temperature. The output voltage can then be converted to a temperature in Kelvin, and correspondingly into °C or °F, by calculations in code.
The voltage that comes out of the sensor is then read by the IoT device, and the device can respond to it. Depending on the sensor, this voltage can be an arbitrary value or can map to a standard unit. For example, an analog temperature sensor based on a [thermistor](https://wikipedia.org/wiki/Thermistor) changes it's resistance depending on the temperature. The output voltage can then be converted to a temperature in Kelvin, and correspondingly into °C or °F, by calculations in code.
✅ What do you think happens if the sensor returns a higher voltage than was sent (for example coming from an external power supply)? ⛔️ DO NOT test this out.
@ -74,7 +74,7 @@ The voltage that comes out the sensor is then read by the IoT device, and the de
IoT devices are digital - they can't work with analog values, they only work with 0s and 1s. This means that analog sensor values need to be converted to a digital signal before they can be processed. Many IoT devices have analog-to-digital converters (ADCs) to convert analog inputs to digital representations of their value. Sensors can also work with ADCs via a connector board. For example, in the Seeed Grove ecosystem with a Raspberry Pi, analog sensors connect to specific ports on a 'hat' that sits on the Pi connected to the Pi's GPIO pins, and this hat has an ADC to convert the voltage into a digital signal that can be sent off the Pi's GPIO pins.
Imagine you have an analog light sensor connected to an IoT device that uses 3.3V, and is returning a value of 1V. This 1V doesn't mean anything in the digital world, so needs to be converted. The voltage will be converted to an analog value using a scale depending on the device and sensor. One example is the Seeed Grove light sensor which outputs values from 0 to 1,023. For this sensor running at 3.3V, a 1V output would be a value of 300. An IoT device can't handle 300 as an analog value, so the value would be converted to `0000000100101100`, the binary representation of 300 by the Grove hat. This would then be processed by the IoT device.
Imagine you have an analog light sensor connected to an IoT device that uses 3.3V and is returning a value of 1V. This 1V doesn't mean anything in the digital world, so needs to be converted. The voltage will be converted to an analog value using a scale depending on the device and sensor. One example is the Seeed Grove light sensor which outputs values from 0 to 1,023. For this sensor running at 3.3V, a 1V output would be a value of 300. An IoT device can't handle 300 as an analog value, so the value would be converted to `0000000100101100`, the binary representation of 300 by the Grove hat. This would then be processed by the IoT device.
✅ If you don't know binary, then do a small amount of research to learn how numbers are represented by 0s and 1s. The [BBC Bitesize introduction to binary lesson](https://www.bbc.co.uk/bitesize/guides/zwsbwmn/revision/1) is a great place to start.
@ -82,7 +82,7 @@ From a coding perspective, all this is usually handled by libraries that come wi
### Digital sensors
Digital sensors, like analog sensors, detect the world around them using changes in electrical voltage. The difference is they output a digital signal, either by only measuring two states, or by using a built-in ADC. Digital sensors are becoming more and more common to avoid the need to use an ADC either in a connector board or on the IoT device itself.
Digital sensors, like analog sensors, detect the world around them using changes in electrical voltage. The difference is they output a digital signal, either by only measuring two states or by using a built-in ADC. Digital sensors are becoming more and more common to avoid the need to use an ADC either in a connector board or on the IoT device itself.
The simplest digital sensor is a button or switch. This is a sensor with two states, on or off.
@ -92,18 +92,18 @@ The simplest digital sensor is a button or switch. This is a sensor with two sta
Pins on IoT devices such as GPIO pins can measure this signal directly as a 0 or 1. If the voltage sent is the same as the voltage returned, the value read is 1, otherwise the value read is 0. There is no need to convert the signal, it can only be 1 or 0.
> 💁 Voltages are never exact especially as the components in a sensor will have some resistance, so there is usually a tolerance. For example the GPIO pins on a Raspberry Pi work on 3.3V, and read a return signal above 1.8V as a 1, below 1.8V as 0.
> 💁 Voltages are never exact especially as the components in a sensor will have some resistance, so there is usually a tolerance. For example, the GPIO pins on a Raspberry Pi work on 3.3V, and read a return signal above 1.8V as a 1, below 1.8V as 0.
* 3.3V goes into the button. The button is off so 0V comes out, giving a value of 0
* 3.3V goes into the button. The button is on so 3.3V comes out, giving a value of 1
More advanced digital sensors read analog values, then convert them using on-board ADCs to digital signals. For example a digital temperature sensor will still use a thermocouple in the same way as an analog sensor, and will still measure the change in voltage caused by the resistance of the thermocouple at the current temperature. Instead of returning an analog value and relying on the device or connector board to convert to a digital signal, an ADC built into the sensor will convert the value and send it as a series of 0s and 1s to the IoT device. These 0s and 1s are sent in the same way as the digital signal for a button with 1 being full voltage and 0 being 0v.
More advanced digital sensors read analog values, then convert them using on-board ADCs to digital signals. For example, a digital temperature sensor will still use a thermocouple in the same way as an analog sensor, and will still measure the change in voltage caused by the resistance of the thermocouple at the current temperature. Instead of returning an analog value and relying on the device or connector board to convert to a digital signal, an ADC built into the sensor will convert the value and send it as a series of 0s and 1s to the IoT device. These 0s and 1s are sent in the same way as the digital signal for a button with 1 being full voltage and 0 being 0v.
***A digital temperature sensor. Temperature by Vectors Market / Microcontroller by Template - all from the [Noun Project](https://thenounproject.com)***
Sending digital data allows sensors to become more complex and send more detailed data, even encrypted data for secure sensors. One example is a camera. This is a sensor that captures an image and sends it as digital data containing that image, usually in a compressed format such as JPEG, to be read by the IoT device. It can even stream video by capturing images and sending either the complete image frame by frame, or a compressed video stream.
Sending digital data allows sensors to become more complex and send more detailed data, even encrypted data for secure sensors. One example is a camera. This is a sensor that captures an image and sends it as digital data containing that image, usually in a compressed format such as JPEG, to be read by the IoT device. It can even stream video by capturing images and sending either the complete image frame by frame or a compressed video stream.
## What are actuators?
@ -143,7 +143,7 @@ One example is a dimmable light, such as the ones you might have in your house.
***A light controlled by the voltage output by an IoT device. Idea by Pause08 / Microcontroller by Template - all from the [Noun Project](https://thenounproject.com)***
***A light controlled by the voltage output of an IoT device. Idea by Pause08 / Microcontroller by Template - all from the [Noun Project](https://thenounproject.com)***
Like with sensors, the actual IoT device works on digital signals, not analog. This means to send an analog signal, the IoT device needs a digital to analog converter (DAC), either on the IoT device directly, or on a connector board. This will convert the 0s and 1s from the IoT device to an analog voltage that the actuator can use.
@ -174,14 +174,14 @@ This means in one second you have 25 5V pulses of 0.02s that rotate the motor, e
***PWM rotation of a motor at 75RPM. motor by Bakunetsu Kaito / Microcontroller by Template - all from the [Noun Project](https://thenounproject.com)***
You can change the motor speed by changing the size of the pulses. For example, with the same motor you can keep the same cycle time of 0.04s, with the on pulse halved to 0.01s, and the off pulse increasing to 0.03s. You have the same number of pulses per second (25), but each on pulse is half the length. A half length pulse only turns the motor one twentieth of a rotation, and at 25 pulses a second will complete 1.25 rotations per second, or 75rpm. By changing the pulse speed of a digital signal you've halved the speed of an analog motor.
You can change the motor speed by changing the size of the pulses. For example, with the same motor you can keep the same cycle time of 0.04s, with the on pulse halved to 0.01s, and the off pulse increasing to 0.03s. You have the same number of pulses per second (25), but each on pulse is half the length. A half length pulse only turns the motor one twentieth of a rotation, and at 25 pulses a second will complete 1.25 rotations per second or 75rpm. By changing the pulse speed of a digital signal you've halved the speed of an analog motor.
```output
25 pulses per second x 0.05 rotations per pulse = 1.25 rotations per second
1.25 rotations per second x 60 seconds in a minute = 75rpm
```
✅ How would you keep the motor rotation smooth, especially at low speeds? Would you use a small number long pulses with long pauses, or lots of very short pulses with very short pauses?
✅ How would you keep the motor rotation smooth, especially at low speeds? Would you use a small number of long pulses with long pauses or lots of very short pulses with very short pauses?
> 💁 Some sensors also use PWM to convert analog signals to digital signals.
@ -189,7 +189,7 @@ You can change the motor speed by changing the size of the pulses. For example,
### Digital actuators
Digital actuators, like digital sensors, either have two states controlled by a high or low voltage, or have a DAC built in so can convert a digital signal to an analog one.
Digital actuators, like digital sensors, either have two states controlled by a high or low voltage or have a DAC built in so can convert a digital signal to an analog one.
One simple digital actuator is an LED. When a device sends a digital signal of 1, a high voltage is sent that lights the LED. When a digital signal of 0 is sent, the voltage drops to 0V and the LED turns off.
@ -207,7 +207,7 @@ More advanced digital actuators, such as screens require the digital data to be
The challenge in the last two lessons was to list as many IoT devices as you can that are in your home, school or workplace and decide if they are built around microcontrollers or single-board computers, or even a mixture of both.
For every device you listed, what sensors and actuators are they connected to? What is the purpose of each sensor and actuator connected to these devices.
For every device you listed, what sensors and actuators are they connected to? What is the purpose of each sensor and actuator connected to these devices?
The Grove LED comes as a module with a selection of LEDs, allowing you to chose the color.
The Grove LED comes as a module with a selection of LEDs, allowing you to choose the color.
#### Task - connect the LED
@ -32,7 +32,7 @@ Connect the LED.
LEDs are light-emitting diodes, and diodes are electronic devices that can only carry current one way. This means the LED needs to be connected the right way round, otherwise it won't work.
One of the legs of the LED is the positive pin, the other is the negative pin. The LED is not perfectly round, and is slightly flatter on one side. The side that is slightly flatter is the negative pin. When you connect the LED to the module, make sure the pin by the rounded side is connected to the socket marked **+** on the outside of the module, and the flatter side is connected to the socket closer to the middle of the module.
One of the legs of the LED is the positive pin, the other is the negative pin. The LED is not perfectly round and is slightly flatter on one side. The slightly flatter side is the negative pin. When you connect the LED to the module, make sure the pin by the rounded side is connected to the socket marked **+** on the outside of the module, and the flatter side is connected to the socket closer to the middle of the module.
1. The LED module has a spin button that allows you to control the brightness. Turn this all the way up to start with by rotating it anti-clockwise as far as it will go using a small Phillips head screwdriver.
The Grove LED comes as a module with a selection of LEDs, allowing you to chose the color.
The Grove LED comes as a module with a selection of LEDs, allowing you to choose the color.
#### Task - connect the LED
@ -32,7 +32,7 @@ Connect the LED.
LEDs are light-emitting diodes, and diodes are electronic devices that can only carry current one way. This means the LED needs to be connected the right way round, otherwise it won't work.
One of the legs of the LED is the positive pin, the other is the negative pin. The LED is not perfectly round, and is slightly flatter on one side. The side that is slightly flatter is the negative pin. When you connect the LED to the module, make sure the pin by the rounded side is connected to the socket marked **+** on the outside of the module, and the flatter side is connected to the socket closer to the middle of the module.
One of the legs of the LED is the positive pin, the other is the negative pin. The LED is not perfectly round, and is slightly flatter on one side. The slightly flatter side is the negative pin. When you connect the LED to the module, make sure the pin by the rounded side is connected to the socket marked **+** on the outside of the module, and the flatter side is connected to the socket closer to the middle of the module.
1. The LED module has a spin button that allows you to control the brightness. Turn this all the way up to start with by rotating it anti-clockwise as far as it will go using a small Phillips head screwdriver.
@ -4,7 +4,7 @@ In this part of the lesson, you will subscribe to commands sent from an MQTT bro
## Subscribe to commands
The next step is to subscribe to the commands sent from the MQTT broker, and respond to them.
The next step is to subscribe to the commands sent from the MQTT broker and respond to them.
### Task
@ -20,7 +20,7 @@ Subscribe to commands.
server_command_topic = id + '/commands'
```
The `server_command_topic` is the MQTT topic the device will subscribe to to receive LED commands.
The `server_command_topic` is the MQTT topic the device will subscribe to receive LED commands.
1. Add the following code just above the main loop, after the `mqtt_client.loop_start()` line:
@ -40,13 +40,13 @@ Subscribe to commands.
This code defines a function, `handle_command`, that reads a message as a JSON document and looks for the value of the `led_on` property. If it is set to `True` the LED is turned on, otherwise it is turned off.
The MQTT client subscribes on the topic that the server will send messages on, and sets the `handle_command` function to be called when a message is received.
The MQTT client subscribes on the topic that the server will send messages on and sets the `handle_command` function to be called when a message is received.
> 💁 The `on_message` handler is called for all topics subscribed to. If you later write code that listens to multiple topics, you can get the topic that the message was sent to from the `message` object passed to the handler function.
1. Run the code in the same way as you ran the code from the previous part of the assignment. If you are using a virtual IoT device, then make sure the CounterFit app is running and the light sensor and LED have been created on the correct pins.
1. Adjust the light levels detected by your physical or virtual device. You will see messages being received and commands being sent in the terminal. You will also see the LED being turned on and off depending on the light level.
1. Adjust the light levels detected by your physical or virtual device. You will see messages being received and commands being sent in the terminal. You will also see the LED is being turned on and off depending on the light level.
> 💁 You can find this code in the [code-commands/virtual-device](code-commands/virtual-device) folder or the [code-commands/pi](code-commands/pi) folder.
@ -6,11 +6,11 @@ In this part of the lesson, you will connect your Wio Terminal to an MQTT broker
## Install the WiFi and MQTT Arduino libraries
To communicate with the MQTT broker, you need to install some Arduino libraries to use the WiFi chip in the Wio Terminal, and communicate with MQTT. When developing for Arduino devices, you can use a wide range of libraries that contain open-source code and implement a huge range of capabilities. Seeed publish libraries for the Wio Terminal that allow it to communicate over WiFi. Other developers have published libraries to communicate with MQTT brokers, and you will be using these with your device.
To communicate with the MQTT broker, you need to install some Arduino libraries to use the WiFi chip in the Wio Terminal, and communicate with MQTT. When developing for Arduino devices, you can use a wide range of libraries that contain open-source code and implement a huge range of capabilities. Seeed publishes libraries for the Wio Terminal that allows it to communicate over WiFi. Other developers have published libraries to communicate with MQTT brokers, and you will be using these with your device.
These libraries are provided as source code that can be imported automatically into PlatformIO, and compiled for your device. This way Arduino libraries will work on any device that supports the Arduino framework, assuming that the device has any specific hardware needed by that library. Some libraries, such as the Seeed WiFi libraries, are specific to certain hardware.
These libraries are provided as source code that can be imported automatically into PlatformIO and compiled for your device. This way Arduino libraries will work on any device that supports the Arduino framework, assuming that the device has any specific hardware needed by that library. Some libraries, such as the Seeed WiFi libraries, are specific to certain hardware.
Libraries can be installed globally and compiled in if needed, or into a specific project. For this assignment, the libraries will be installed into the project.
Libraries can be installed globally and compiled if needed, or into a specific project. For this assignment, the libraries will be installed into the project.
✅ You can learn more about library management and how to find and install libraries in the [PlatformIO library documentation](https://docs.platformio.org/en/latest/librarymanager/index.html).
@ -33,7 +33,7 @@ Install the Arduino libraries.
This imports the Seeed WiFi libraries. The `@ <number>` syntax refers to a specific version number of the library.
> 💁 You can remove the `@ <number>` to always use the latest version of the libraries, but there's no guarantees the later versions will work with the code below. The code here has been tested with this version of the libraries.
> 💁 You can remove the `@ <number>` to always use the latest version of the libraries, but there are no guarantees the later versions will work with the code below. The code here has been tested with this version of the libraries.
This is all you need to do to add the libraries. Next time PlatformIO builds the project it will download the source code for these libraries and compile it into your project.
@ -142,7 +142,7 @@ Connect to the MQTT broker.
const string CLIENT_NAME = ID + "nightlight_client";
```
Replace `<ID>` with a unique ID that will be used the name of this device client, and later for the topics that this device publishes and subscribes to. The *test.mosquitto.org* broker is public and used by many people, including other students working through this assignment. Having a unique MQTT client name and topic names ensures your code won't clash with anyone elses. You will also need this ID when you are creating the server code later in this assignment.
Replace `<ID>` with a unique ID that will be used the name of this device client, and later for the topics that this device publishes and subscribes to. The *test.mosquitto.org* broker is public and used by many people, including other students working through this assignment. Having a unique MQTT client name and topic names ensures your code won't clash with anyone else's. You will also need this ID when you are creating the server code later in this assignment.
> 💁 You can use a website like [GUIDGen](https://www.guidgen.com) to generate a unique ID.
@ -157,7 +157,7 @@ Connect to the MQTT broker.
PubSubClient client(wioClient);
```
This code creates a WiFi client using the Wio Terminal WiFI libraries, and uses it to create an MQTT client.
This code creates a WiFi client using the Wio Terminal WiFI libraries and uses it to create an MQTT client.
1. Below this code, add the following:
@ -183,7 +183,7 @@ Connect to the MQTT broker.
}
```
This function tests the connection to the MQTT broker and reconnects if it is not connected. It loops all the time it is not connected, and attempts to connect using the unique client name defined in the config header file.
This function tests the connection to the MQTT broker and reconnects if it is not connected. It loops all the time it is not connected and attempts to connect using the unique client name defined in the config header file.
If the connection fails, it retries after 5 seconds.
@ -215,7 +215,7 @@ Connect to the MQTT broker.
This code starts by reconnecting to the MQTT broker. These connections can be broken easily, so it's worth regularly checking and reconnecting if necessary. It then calls the `loop` method on the MQTT client to process any messages that are coming in on the topic subscribed to. This app is single-threaded, so messages cannot be received on a background thread, therefore time on the main thread needs to be allocated to processing any messages that are waiting on the network connection.
Finally a delay of 2 seconds ensures the light levels are not sent too often and reduces the power consumption of the device.
Finally, a delay of 2 seconds ensures the light levels are not sent too often and reduces the power consumption of the device.
1. Upload the code to your Wio Terminal, and use the Serial Monitor to see the device connecting to WiFi and MQTT.
Manvi Jha
3 years ago
committed by
GitHub