RaspberryIO - Getting started

By Carlos Solorzano - 05 Sep 2019
Raspberry RaspberryIO IoT API .NET

RaspberryIO is an easy-to-use open-source API to bring the .NET power to the python-centered Raspberry Pi development world.

RaspberryIO enables developers to use the various Raspberry Pi’s hardware modules including the Camera to capture images and video, the GPIO pins, and both SPI and I2C buses.

RaspberryIO works as a high-level wrapper for low-level libraries that interacts directly with the Raspberry Pi hardware, as a result, several implementations could be done, targeting distinct low-level libraries. By now, we have fully implemented the WiringPi library and we are working in the PiGpio implementation.

Using RaspberryIO

On this initial post, we are going to create a new console project to obtain general system information, deploying the project to the Raspberry Pi and finally run the application using .Net Core.

Create the project

  • Open Visual Studio and create a new Console App project.
  • Add the RaspberryIO nuget package. This library Contains classes to control general Raspberry Pi modules like Camera, Audio, Network and classes to get general system information.

      PM> Install-Package Unosquare.Raspberry.IO  
    
  • Add the code to get general system information:

      using System;  
      using Unosquare.RaspberryIO;  
      
      class Program  
      {  
          static void Main(string[] args)  
          {  
              Console.WriteLine(Pi.Info);  
              Console.ReadLine();  
          }  
      }  
    

Unosquare.RaspberryIO.Pi is your access point to the API. Through this static class you can access all API features. The Info property provides access to the SystemInfo class, this class allows you to obtain different system information, like board model, board revision, processor model, memory size, operating system, etc. In the above code, we are writing to the console the SystemInfo class, which ToString overload is going to get the most common system information, nevertheless, you can access individual SystemInfo’s properties to get more specific and useful information.

Note: In future blog entries we are going to explore more features of the Pi class, like Gpio that allow access to the General Purpose Input/Output pins.

Deploy to Raspberry Pi

To deploy you application to the Raspberry you have two options:

  1. Publish your project from VS and then copying all the published files to the Raspberry using some FTP tool like FileZilla.
  2. Use a tool that publishes the project and copy the files to the Raspberry automatically, like sshdeploy.

For this tutorial, we are going to use sshdeploy, a CLI utility that enables quick deployments over SSH. This app was specifically designed to streamline .NET application development for the Raspberry Pi.

To install sshdeploy, open windows command prompt and run the next command:

dotnet tool install -g dotnet-sshdeploy  

Add the next basic configuration to your csproj file:

<PropertyGroup>  
    <OutputType>Exe</OutputType>  
    <TargetFramework>netcoreapp2.2</TargetFramework>  
    <RuntimeIdentifier>linux-arm</RuntimeIdentifier>  
    <SelfContained>false</SelfContained>  
    <SshDeployClean />  
    <SshDeployHost>192.168.1.100</SshDeployHost>  
    <SshDeployUsername>pi</SshDeployUsername>  
    <SshDeployPassword>raspberry</SshDeployPassword>  
    <SshDeployTargetPath>/home/pi/demo</SshDeployTargetPath>  
</PropertyGroup>  

Note 1: To use sshdeploy, SSH must be enabled in the Raspberry Pi. To enable SSH in the Raspberry Pi follow this tutorial.

Note 2: You must use your actually Raspberry Pi IP address, user and password.

Finally, to actually deploy the app to the Raspberry Pi, open windows command prompt, navigate to the path where the csproj file is and run the next command:

dotnet-sshdeploy push -c Release  

The utility will publish the app and then will copy the required files to the specified path (SshDeployTargetPath).

Run the app

In order to run the application you need to install .NET Core SDK or runtime. The software development kit (SDK) includes everything you need to build and run .NET Core applications, using command line tools and any editor (including Visual Studio). The runtime includes just the resources required to run existing .NET Core applications. The runtime is included in the SDK.

Since we only need to run an existing application on the Raspberry Pi, we are going to install only the .NET Core runtime.

To install .NET Core runtime execute the following commands:

sudo apt-get -y update  
sudo apt-get -y install libunwind8 gettext  
wget https://download.visualstudio.microsoft.com/download/pr/428aaa32-f66c-4847-b845-aa21f90504e4/1cf033db866414997140c2672bd75069/dotnet-runtime-2.2.6-linux-arm.tar.gz  
sudo mkdir /opt/dotnet  
sudo tar -xvf dotnet-runtime-2.2.6-linux-arm.tar.gz -C /opt/dotnet/  
sudo ln -s /opt/dotnet/dotnet /usr/local/bin  

This will install the latest version of .NET Core (2.2.6 at the moment). To verify the version of .NET Core run dotnet --info, you will see something like the next info message:

Host (useful for support):  
  Version: 2.2.6  
  Commit:  7dac9b1b51  
  
.NET Core SDKs installed:  
  No SDKs were found.  
  
.NET Core runtimes installed:  
  Microsoft.NETCore.App 2.2.6 [/opt/dotnet/shared/Microsoft.NETCore.App]  
  
To install additional .NET Core runtimes or SDKs:  
  https://aka.ms/dotnet-download  

Note: To check for newer versions of the .NET Core runtime (or SDK) visit https://aka.ms/dotnet-download.

Finally, navigate to the path where you publish your application and run it using the next command:

dotnet GettingStarted.dll  

You will see some basic system information, something like this:

System Information  
        LibraryVersion        :  
        RaspberryPiVersion    : Pi3ModelBPlusSony  
        BoardRevision         : 0  
        ProcessorCount        : 4  
        InstalledRam          : 971063296  
        IsLittleEndian        : True  
        ModelName             : ARMv7 Processor rev 4 (v7l)  
        Features              : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32  
        CpuImplementer        : 0x41  
        CpuArchitecture       : 7  
        CpuVariant            : 0x0  
        CpuPart               : 0xd03  
        CpuRevision           : 4  
        Hardware              : BCM2835  
        Revision              : a020d3  
        RevisionNumber        : 3  
        Serial                : 00000000299744e5  
        UptimeTimeSpan        : 00:50:29.9800000  

That’s all for this basic example. This was your first contact with RaspberryIO. In future blog entries, we are going to see more examples to go deeper in the API, using more hardware-related features, like the GPIO, the basic means to the Raspberry Pi to communicate with external devices.

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