Where do we start with IoT?
For many developers, IoT brings thoughts of electronics and wires with hours of trying to get things working just to blink an LED or read the temperature of the room with a BME280. You may even be thinking you need to be down low level with C/C++ or Python for your code.
However, if you’re reading this I am guessing you’re a .NET developer and thinking that you can’t use your existing C# .NET skills for IoT. Well, the good news is that you’re wrong, we can. And in this short series of blog posts, I will show you how you can program a small low powered device to connect to the cloud and stream sensor data for analytics and storage.
In this post, we will cover the options we have for the devices and the pros and cons, to help you pick what best suits your project needs.
What is IoT?
You probably already know what IoT stands for Internet Of Things but what does that really mean and where did it come from?
Back when I started out with electronics, working in the automotive industry at Ford Motor Company, I was trained in skills like soldering and electronics using resistors and capacitors as well as integrated circuits (ICs).
This was mainly using PIC and AVR microcontrollers (the 2 main brands), but these required you to have an understanding of electronics as well as the special integrated developer environments (IDEs) and toolchains to program them. This is before you even started with the low-level C/C++ code with their own special instructions.
These chips were the brains of our solution and much like your PC/laptop you’re reading this on, they have a CPU, but also many other parts that make them into a microcontroller.
Now I hear you ask what is a microcontroller as that is not always understood but if we check out Wikipedia it states:
“A microcontroller (MCU for microcontroller unit) is a small computer on a single metal-oxide-semiconductor (MOS) VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Program memory in the form of ferroelectric RAM, NOR flash or OTP ROM is also often included on chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general-purpose applications consisting of various discrete chips.”
So basically, a computer all on one chip is the easy answer. Just no video card and the ability to turn real-world things on/off or sense the values from various sensors it’s connected to.
Starting with Arduino
A lot of online resources and blog posts for getting started with IoT will mention the amazing Arduino family of products. These are small form factor boards that were designed using the AVR Micro mentioned above but into an easy-to-use and pre-built package.
They have their own IDE which, to be honest, isn’t the best as it’s essentially Notepad++ with a few extra bits. However, you can use VSCode or you can even use full-fat Visual Studio but you will need the awesome Visual Micro which is what I use when I am low level on client projects.
When using Arduino and the cut-down version of C/C++ that the platform uses (after all there is no need for the full C/C++), you are not stuck with just the Arduino products. Due to the success of the Arduino platform from 2005 onwards, there are many compatible boards from the likes of PRJC – Teensy and Adafruit to name just two.
WARNING – Visiting the stores to look at these boards and sensors may result in purchases 😉
But you said .NET and C# for IoT?
Once you have played with the Arduino and built that Blinky LED sample that is the typical IoT Hello world project, you will want to learn how to leverage your .NET skills.
The good news is that the ‘world’s most Okayest developer’ as he calls himself Scott Hanselman, stood on stage at .NET Conf in 2021 and said that .NET runs everywhere.
But how do we do this?
We have three choices really, first, there is the amazing Raspberry Pi. Then in line with the Arduino boards mentioned before, there is the Meadow F7 from Wilderness labs. Or using off-the-shelf boards like an ESP32/STM32, you can use the Nano Framework platform.
Let’s take a look at each of these.
The Raspberry Pi is a platform that has been around for a decade now, with the first model showing up in 2012. It is based on a Broadcom CPU from Android Mobile phones of the time. The board is a full Linux machine, and the aim has always been to keep the price of the board to £35 and build a learning platform for kids around it.
In fact profits from selling the boards and associated items are fed back into not just R&D but the RaspberryPi Foundation which aims to teach kids to code. So you can make your purchase with a smile, thinking of that.
They are not just for schools, colleges and universities though, they are used in many products and industries globally as they are small, cheap Linux machines to host your code.
With a 40-pin header full of GPIO (General Purpose Input/Output), you can connect a whole host of sensors and peripherals to the boards. Add in the HDMI ports for a Monitor and Ethernet/Wi-Fi etc you can easily see it’s just a small PC the size of a credit card at a super low price.
This means that you can run .NET, and the easy way to do this is to use a script from a good friend of mine, Pete Gallagher which is available here. It has the added bonus that he walks you through your very first .NET program to blink the LED.
Learn more about Raspberry Pi
As Pete shows in the blog, you will be writing a .NET Console App that will interact with the outside world using the IoT Device Binding which you can read about over on the Docs.Microsoft pages.
If you want to learn more, you can even complete a fantastic Microsoft Learn course, which takes less than an hour and teaches you the basics of using .NET on these fantastic little boards.
If you wanted to use the HMDI and a screen for your project you could also build a Xamarin.Forms Project as it has a Linux Target that is community built. I have successfully used this to build advertising displays of a screen with a RPi on the back running a Xamarin project. Though this isn’t really IoT, it’s still a great use of the tech stack.
Pros and Cons of the Raspberry Pi
- Full Linux Machine so have the full power of .Net
- Have network onboard with Ethernet and Wi-Fi
- HDMI so you can connect a monitor
- Can run VSCode IDE on the board, so it’s easy to develop for out in the field.
- Lots of add-on boards called HAT’s available with the Library’s pre-written.
- Larger form factor than other boards.
- Needs a lot of power the RPi (Shorthand for Raspberry Pi) 4 board needs 600mA just to run and is recommended to use a 3A power supply – so it’s not going to run from a battery.
The next on our list of choices is the Meadow F7 from Wilderness Labs, this board is designed, produced and sold by Wilderness Labs in their Store for $50 plus shipping from the USA.
The team behind the Meadow boards are all ex-Xamarin from when Microsoft purchased them, so they are used to building .NET code on top of Mono Runtime to run on non-windows devices, and this is exactly what is happening here.
More about Meadow F7
As you can see from the bottom of the stack, we have an RTOS which is a Real-Time Operating System and that runs Mono which then supports .NET standard.
On top of the base runtime, we have the Meadow.Core which is all the libraries we interact with from our .NET C# code and the Meadow.Foundation is a selection of NuGet library’s that we can add to our project to interact with the sensors and peripherals we use in our project – all in C#.
We write our code in Visual Studio using the Wilderness Labs extension, which is available for both VS19 and VS22 here. Don’t worry, the totally free Visual Studio Community Edition is more than enough to use this awesome platform.
We then write in a style that is borrowed from Xamarin (as you would guess given the team’s background) and deploy from your machine to the board. The best place to start with Meadow is to get a board from the store and follow the docs they have here, there are 2 versions of the hardware V1 and V2. The current sale board is the V2 so be sure to grab that as it has some fixes.
As for the firmware on the board, it’s currently at Beta 6.4 and there is a roadmap here that has just been published showing v1.0 so hopefully, there will be an RC very soon.
Pros and Cons of Meadow F7
- Same Form Factor as the Adafruit feather Boards so there are many add-ons available called Feather Wings.
- .NET Standard 2.0 so all your favourite Nugets should work like NewtonSoft.JSON etc.
- Onboard Wi-Fi and Bluetooth for connection to the outside world for networking and connecting to the cloud.
- Low Power so can run from a battery for many weeks or a Solar Cell for months if not indefinitely.
- You are not stuck with C#, if you’re an F# fan or crazy, and use VB.Net (yes it’s still a thing), look you really can use whatever .NET language you want as it’s just .NET.
- It has a 2nd microcontroller onboard an ESP32 that handles the network stack mainly but is also used to allow Over-The-Air (OTA) updates from the cloud when your device is out in the field.
- My main concern with the Meadow F7 is they are a small company and the only supplier of the boards, but I love them so hopefully, they stick around.
- Planned Over The Air Updates (More on this in a future post!) are from a Wilderness Labs cloud offering rather than one of the main cloud providers like Azure. This is still in development so may change.
- Still in Beta for the software at the time of writing and have been for a while, hopefully, they will RC soon and support .NET 6 in the process so watch this space.
The last of our choices, but certainly not the least, is the amazing Nano Framework project. This is an Open-Source platform that allows you to write managed C# applications for constrained embedded devices and isn’t tied to just one device or even one processor.
You can target a range of devices from the ESP32, STM32, M5Stack, Texas Instruments and NXP families as well as other community lead targets. You can see the full list on their GitHub page at the bottom as well as a link to the many community targets getting some love.
The difference with the Nano Framework is that rather than being full .NET like the RPi or Net Standard like the Meadow; this is C# wrappers around C++ libraries to build the HAL (Hardware Abstraction Layer) and PAL (Platform Abstraction Layer) to surface the device to a reduced .NET CLR (Common Language Runtime).
More about The Nano Framework
What this means is that you can write your normal C# code in a console app like the other devices we have mentioned. However, unlike the others, as these devices have very little memory and are super low-powered, we have some bits of .NET missing like Generics for example. In essence, as the team say, it’s a reduced version of the .NET Common Language Runtime (CLR). And it features a subset of the .NET base class libraries along with the most common APIs included in .NET IoT allowing code reuse from .NET IoT applications.
The big advantage of the Nano Framework, other than it being open source so you can dive in and help out or write a library for that obscure sensor you need, is that it supports so many devices. All these devices are very cheap, for example, an ESP32 board can be purchased cheaply even from Amazon.
As with Meadow, there is a Visual Studio Extention for VS17/VS19 and VS22 and no special tools are needed other than the board and a USB cable for most devices.
Pros and Cons of the Nano Framework
- Open Source and backed/supported by the .NET Foundation.
- Multiple devices from huge suppliers like Espressif
- Runs at super low power and you have access on most devices to the underlying platform (like Xamarin/MAUI really!) so you can do low-level things on each device like deep sleep.
- Not full .NET but wrappers so not everything is supported.
- Different boards have different capabilities, not all have Wi-Fi/Bluetooth, so you have to research your perfect device before starting the project.
- Need to use the CLI to burn the bootloader onto your new device before you can export your .NET C# code onto it. This can be a very daunting process and where most people have issues when getting started.
In the first of this series of posts, we have looked at what IoT devices we can target with our .NET and C# skills. As well as the pros and cons of each platform and approach. In the next, we will look at the ways to connect these devices to the cloud and the services we have available to us. As after all, without that there really isn’t an ‘I’ in IoT is there?
You can now catch part 2, where we dive into connection to the cloud here and part 3, a look at using your data within the cloud here.
If there is anything specific, you want to be covered or you wish to comment then please do reach out on Twitter @CliffordAgius. Or you can contact the Ballard Chalmers team.