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.
Manvi Jha
4 years ago
committed by
GitHub