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The Raspberry Pi's IO Functionality in an easy-to-use API for .NET (Mono/.NET Core). Our mission is to make .NET a first-class citizen in the Python-centric community of Raspberry Pi developers.
- Features
- Installation
- Running the latest version of Mono
- Running .NET Core 2
- The Camera Module
- Obtaining Board and System Information
- Using the GPIO Pins
- Using the SPI Bus
- I2C to connect ICs
- Timing and Threading
- Serial Ports (UART)
- Similar Projects
This library enables developers to use the various Raspberry Pi's hardware modules:
Pi.CameraProvides access to the official Raspberry Pi Camera module.Pi.InfoProvides information on this Raspberry Pi's CPU and form factor.Pi.GpioProvides access to the Raspberry Pi's GPIO as a collection of GPIO Pins.Pi.SpiProvides access to the 2-channel SPI bus.Pi.I2cProvides access to the functionality of the i2c bus.Pi.TimingProvides access to The PI's Timing and threading API.
Please note you program needs to be run with sudo. Example sudo mono myprogram.exe in order to work correctly.
This library depends on the wonderful WiringPi library available here. You do not need to install this library yourself. The RaspberryIO assembly will automatically extract the compiled binary of the library in the same path as the entry assembly.
We offer an additional package with helpful classes to use peripherals, many of them are from pull requests from our contributors. The current set of peripherals supported are:
- Infrared Sensor HX-1838
- Led Strip APA-102C
- NFC/RFID Controller MFRC-522
- Temperature Sensor AM-2302
- Generic Button
Install basic Raspberry.IO package:
PM> Install-Package Unosquare.Raspberry.IO
Install Raspberry.IO Peripherals package:
PM> Install-Package Unosquare.RaspberryIO.Peripherals
It is recommended that you install the latest available release of Mono because what is available in the Raspbian repo is quite old (3.X). These commands were tested using Raspbian Jessie. The version of Mono that is installed at the time of this writing is:
Mono JIT compiler version 5.4.1.6 (tarball Wed Nov 8 21:42:16 UTC 2017)
The commands to get Mono installed are the following:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install mono-complete
sudo apt-get install dirmngr
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install mono-complete
sudo apt-get install dirmngr
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb http://download.mono-project.com/repo/debian stretch main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list
sudo apt-get update
sudo apt-get dist-upgrade
Now, verify your version of Mono by running mono --version. Version 4.6 and above should be good enough.
In order to setup Wi-Fi, run: sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
A good file should look like this:
country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
ssid="your_real_wifi_ssid"
scan_ssid=1
psk="your_real_password"
}
And then restart the services as follows:
sudo systemctl daemon-reload
sudo systemctl restart dhcpcd
You can also configure most boot options by running: sudo raspi-config
This project can also run in .NET Core 2.
Run the following commands to install .NET Core 2.
# Update Ubuntu 16.04
sudo apt-get -y update
# Install the packages necessary for .NET Core
sudo apt-get -y install libunwind8 libunwind8-dev gettext libicu-dev liblttng-ust-dev libcurl4-openssl-dev libssl-dev uuid-dev
# Download the latest binaries for .NET Core 2
wget https://dotnetcli.blob.core.windows.net/dotnet/Runtime/release/2.0.0/dotnet-runtime-latest-linux-arm.tar.gz
# Make a directory for .NET Core to live in
mkdir ~/dotnet
# Unzip the binaries into the directory you just created
tar -xvf dotnet-runtime-latest-linux-arm.tar.gz -C ~/dotnet
# Now add the path to the dotnet executable to the environment path
# This ensures the next time you log in, the dotnet exe is on your path
cd /home/pi/dotnet
echo "PATH=\$PATH:/home/pi/dotnet" >> dotnetcore.sh
sudo mv dotnetcore.sh /etc/profile.d
# Then run the command below to add the path to the dotnet executable to the current session
PATH=$PATH:/home/ubuntu/dotnet
# finally, you can:
sudo nano /etc/sudoers
# and append to the secure_path option:
:/home/pi/dotnet
# this will allow you to run dotnet in su mode
After that, you can reboot the raspberry. To check if dotnet is installed just run "dotnet" and a message should show. If you run into issues with error messages such as framework not found '2.0.0', it must be because the latest version might not be a stable version and the runtime is not rolled forward utomatically in this case. A simple solution is to create a 2.0.0 runtime symlink based on the current version. See the following link for detailed info: https://github.com/dotnet/cli/issues/7543
pi@localhost~$ dotnet
Usage: dotnet [options]
Usage: dotnet [path-to-application]
Options:
-h|--help Display help.
--version Display version.
path-to-application:
The path to an application .dll file to execute.
- You need to publish the project and you can accomplish this by using dotnet-sshdeploy but first, you must edit these properties inside the Playground's csproj file in order to establish an ssh connection with your raspberry
<SshDeployHost>172.16.17.54</SshDeployHost>
<SshDeployTargetPath>/home/pi/Playground</SshDeployTargetPath>
<SshDeployUsername>pi</SshDeployUsername>
<SshDeployPassword>raspberry</SshDeployPassword>- Execute
dotnet sshdeploy pushin the same folder where Unosquare.RaspberryIO.Playground.csproj resides and if everything executes correctly you should see an output like this:
SSH Deployment Tool [Version 0.1.6.0]
(c)2015 - 2017 Unosquare SA de CV. All Rights Reserved.
For additional help, please visit https://github.com/unosquare/sshdeploy
Deploying...
Configuration Debug
Framework netcoreapp2.0
Source Path C:\raspberryio\src\Unosquare.RaspberryIO.Playground\bin\Debug\netcoreapp2.0\publish
Excluded Files .ready|.vshost.exe|.vshost.exe.config
Target Address 192.16.17.54:22
Username pi
Target Path /home/pi/Playground
Clean Target NO
Pre Deployment
Post Deployment
Connecting to host 192.16.17.54:22 via SSH.
Connecting to host 192.16.17.54:22 via SFTP.
Deploying 8 files.
Finished deployment in 1.25 seconds.
Completed.
- The default TargetFramework is
netcoreapp2.0but you can change this by either modifying the RuntimeIdentifier property inside the csproj file or supplying it as a parameter like thisdotnet sshdeploy -f net452. More information about dotnet-sshdeploy see this
- Give permissions to run the project
ubuntu@ubuntu:~/publish$ sudo chmod u+x *
- Run the project
ubuntu@ubuntu:~/publish$ ./Unosquare.RaspberryIO.Playground
The Pi.Camera module uses raspivid and raspistill to access the camera so they must be installed in order for your program to work properly. raspistill arguments are specified in an instance of the CameraStillSettings class, while the raspivid arguments are specified in an instance of the CameraVideoSettings class.
The Pi.Camera.CaptureImage* methods simply return an array of bytes containing the captured image. There are synchronous and asynchronous falvors of these methods so you can use the familiar async and await pattern to capture your images. All raspistill arguments (except for those that control user interaction such as -k) are available via the CameraStillSettings. To start, create a new instance of the CameraStillSettings class and pass it on to your choice of the Pi.Camera.CaptureImage* methods. There are shortcut methods available that simply take a JPEG image at the given Width and Height. By default, the shortcut methods set the JPEG quality at 90%.
Example using a shortcut method:
static void TestCaptureImage()
{
var pictureBytes = Pi.Camera.CaptureImageJpeg(640, 480);
var targetPath = "/home/pi/picture.jpg";
if (File.Exists(targetPath))
File.Delete(targetPath);
File.WriteAllBytes(targetPath, pictureBytes);
Console.WriteLine($"Took picture -- Byte count: {pictureBytes.Length}");
}Example using a CaptureImage method:
// TODO: example code hereCapturing video streams is somewhat different but it is still very easy to do. The concept behind it is to Open a video stream providing your own callback. When opening the stream Raspberry IO will spawn a separate thread and will not block the execution of your code, but it will continually call your callback method containing the bytes that are being read from the camera until the Close method is called or until the timeout is reached.
Example of capturing a stream of H.264 video
static void TestCaptureVideo()
{
// Setup our working variables
var videoByteCount = 0;
var videoEventCount = 0;
var startTime = DateTime.UtcNow;
// Configure video settings
var videoSettings = new CameraVideoSettings()
{
CaptureTimeoutMilliseconds = 0,
CaptureDisplayPreview = false,
ImageFlipVertically = true,
CaptureExposure = CameraExposureMode.Night,
CaptureWidth = 1920,
CaptureHeight = 1080
};
try
{
// Start the video recording
Pi.Camera.OpenVideoStream(videoSettings,
onDataCallback: (data) => { videoByteCount += data.Length; videoEventCount++; },
onExitCallback: null);
// Wait for user interaction
startTime = DateTime.UtcNow;
Console.WriteLine("Press any key to stop reading the video stream . . .");
Console.ReadKey(true);
}
catch (Exception ex)
{
Console.WriteLine($"{ex.GetType()}: {ex.Message}");
}
finally
{
// Always close the video stream to ensure raspivid quits
Pi.Camera.CloseVideoStream();
// Output the stats
var megaBytesReceived = (videoByteCount / (1024f * 1024f)).ToString("0.000");
var recordedSeconds = DateTime.UtcNow.Subtract(startTime).TotalSeconds.ToString("0.000");
Console.WriteLine($"Capture Stopped. Received {megaBytesReceived} Mbytes in {videoEventCount} callbacks in {recordedSeconds} seconds");
}
}RaspberryIO contains useful utilities to obtain information about the board it is running on. You can simply call the Pi.Info.ToString() method to obtain a dump of all system properties as a single string, or you can use the individual properties such as Installed RAM, Processor Count, Raspberry Pi Version, Serial Number, etc. There's not a lot more to this.
Please note Pi.Info depends on Wiring Pi, and the /proc/cpuinfo and /proc/meminfo files.
Pin reference for the B plus (B+) - Header P1
| BCM | wPi | Name | Mode | V | L | R | V | Mode | Name | wPi | BCM |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 3.3v | 01 | 02 | 5v | ||||||||
| 2 | 8 | SDA.1 | ALT0 | 1 | 03 | 04 | 5V | ||||
| 3 | 9 | SCL.1 | ALT0 | 1 | 05 | 06 | 0v | ||||
| 4 | 7 | GPIO. 7 | IN | 1 | 07 | 08 | 1 | ALT0 | TxD | 15 | 14 |
| 0v | 09 | 10 | 1 | ALT0 | RxD | 16 | 15 | ||||
| 17 | 0 | GPIO. 0 | IN | 0 | 11 | 12 | 0 | IN | GPIO. 1 | 1 | 18 |
| 27 | 2 | GPIO. 2 | IN | 0 | 13 | 14 | 0v | ||||
| 22 | 3 | GPIO. 3 | IN | 0 | 15 | 16 | 0 | IN | GPIO. 4 | 4 | 23 |
| 3.3v | 17 | 18 | 0 | IN | GPIO. 5 | 5 | 24 | ||||
| 10 | 12 | MOSI | IN | 0 | 19 | 20 | 0v | ||||
| 9 | 13 | MISO | IN | 0 | 21 | 22 | 0 | IN | GPIO. 6 | 6 | 25 |
| 11 | 14 | SCLK | IN | 0 | 23 | 24 | 1 | IN | CE0 | 10 | 8 |
| 0v | 25 | 26 | 1 | IN | CE1 | 11 | 7 | ||||
| 0 | 30 | SDA.0 | IN | 1 | 27 | 28 | 1 | IN | SCL.0 | 31 | 1 |
| 5 | 21 | GPIO.21 | IN | 1 | 29 | 30 | 0v | ||||
| 6 | 22 | GPIO.22 | IN | 1 | 31 | 32 | 0 | IN | GPIO.26 | 26 | 12 |
| 13 | 23 | GPIO.23 | IN | 0 | 33 | 34 | 0v | ||||
| 19 | 24 | GPIO.24 | IN | 0 | 35 | 36 | 0 | IN | GPIO.27 | 27 | 16 |
| 26 | 25 | GPIO.25 | IN | 0 | 37 | 38 | 0 | IN | GPIO.28 | 28 | 20 |
| 0v | 39 | 40 | 0 | IN | GPIO.29 | 29 | 21 |
But wait for a second, Where are Wiring Pi (wPi) pins 17 through 20? The above diagram shows the pins of GPIO Header P1. There is an additional GPIO header on the Pi called P5. More info available here
In order to access the pins, use Pi.Gpio. The pins can have multiple behaviors and fortunately Pi.Gpio can be iterated, addressed by index, addressed by Wiring Pi pin number and provides the pins as publicly accessible properties.
Here is an example of addressing the pins in all the various ways:
public static void TestLedBlinking()
{
// Get a reference to the pin you need to use.
// All 3 methods below are exactly equivalent
var blinkingPin = Pi.Gpio[0];
blinkingPin = Pi.Gpio[WiringPiPin.Pin00];
blinkingPin = Pi.Gpio.Pin00;
// Configure the pin as an output
blinkingPin.PinMode = GpioPinDriveMode.Output;
// perform writes to the pin by toggling the isOn variable
var isOn = false;
for (var i = 0; i < 20; i++)
{
isOn = !isOn;
blinkingPin.Write(isOn);
System.Threading.Thread.Sleep(500);
}
}All pins have handy properties and methods that you can use to drive them. For example, you can examine the Capabilities property to find out which features are available on the pin. You can also use the PinMode property to get or set the operating mode of the pin. Please note that the value of the PinMode property is by default set to Input and it will return the last mode you set the property to.
It is very easy to read and write values to the pins. In general, it is a 2-step process.
- Set the pin mode
- Read or write the bit value
Reading the value of a pin example:
Pi.Gpio.Pin02.PinMode = GpioPinDriveMode.Input;
// The below lines are reoughly equivalent
var isOn = Pi.Gpio.Pin02.Read(); // Reads as a boolean
var pinValue = Pi.Gpio.Pin02.ReadValue(); // Reads as a GpioPinValueWriting to a pin example
Pi.Gpio.Pin02.PinMode = GpioPinDriveMode.Output;
// The below lines are reoughly equivalent
Pi.Gpio.Pin02.Write(true); // Writes a boolean
Pi.Gpio.Pin02.Write(GpioPinValue.High); // Writes a pin valueTODO
TODO
TODO
You can emit tones by using SoftToneFrequency. Example:
// Get a reference to the pin
var passiveBuzzer = Pi.Gpio[WiringPiPin.Pin01];
// Set the frequency to Alto Do (523Hz)
passiveBuzzer.SoftToneFrequency = 523
// Wait 1 second
System.Threading.Thread.Sleep(1000);
// And stop
passiveBuzzer.SoftToneFrequency = 0;Register an Interrupt Callback example:
using System;
using Unosquare.RaspberryIO;
using Unosquare.RaspberryIO.Gpio;
class Program
{
// Define the implementation of the delegate;
static void ISRCallback()
{
Console.WriteLine("Pin Activated...");
}
static void Main(string[] args)
{
Console.WriteLine("Gpio Interrupts");
var pin = Pi.Gpio.Pin00;
pin.PinMode = GpioPinDriveMode.Input;
pin.RegisterInterruptCallback(EdgeDetection.FallingEdge, ISRCallback);
Console.ReadKey();
}
}I really liked the following description from Neil's Log Book: The SPI (Serial Peripheral Interface) protocol behaves like a ring buffer so that whenever the master sends a byte to the slave, the slave sends a byte back to the master. The slave can use this behavior to return a status byte, a response to a previous byte, or null data (the master may choose to read the returned byte or ignore it). The bus operates on a 4-wire interface.
RaspberryIO provides easy access to the 2 SPI channels available on the Raspberry. The functionality depends on Wiring Pi's SPI library. Please note that you may need to issue the command gpio load spi before starting your application (or as a System.Diagnostics.Process when your application starts) if the SPI kernel drivers have not been loaded.
In order to use an SPI channel you MUST always set the Channel0Frequency or Channel1Frequency (depending on the channel you want to use) before calling the SendReceive method. If the property is not set beforehand the SPI channel will fail initialization. See an example below:
Example of using the SPI Bus
Pi.Spi.Channel0Frequency = SpiChannel.MinFrequency;
var request = System.Text.Encoding.ASCII.GetBytes("HELLO!");
var response = Pi.Spi.Channel0.SendReceive(request);The Inter IC Bus (I2C) is a cousin of the SPI bus but it is somewhat more complex and it does not work as a ring buffer like the SPI bus. It also connects all of its slave devices in series and depends on 2 lines only. There is a nice tutorial on setting up and using the I2C bus at Robot Electronics. From their site: The physical bus is just two wires, called SCL and SDA. SCL is the clock line. It is used to synchronize all data transfers over the I2C bus. SDA is the data line. The SCL & SDA lines are connected to all devices on the I2C bus. There needs to be a third wire which is just the ground or 0 volts. There may also be a 5volt wire is power is being distributed to the devices. Both SCL and SDA lines are "open drain" drivers. What this means is that the chip can drive its output low, but it cannot drive it high. For the line to be able to go high you must provide pull-up resistors to the 5v supply. There should be a resistor from the SCL line to the 5v line and another from the SDA line to the 5v line. You only need one set of pull-up resistors for the whole I2C bus, not for each device.
RaspberryIO provides easy access to the I2C bus available on the Raspberry. The functionality depends on Wiring Pi's I2C library. Please note that you may need to issue the command gpio load i2c before starting your application (or as a System.Diagnostics.Process when your application starts) if the I2C kernel drivers have not been loaded. The default baud rate is 100Kbps. If you wish to initialize the bus at a different baud rate you may issue, for example, gpio load i2c 200. This will load the bus at 200kbps.
In order to detect I2C devices, you could use the i2cdetect system command. Just remember that on a Rev 1 Raspberry Pi it's device 0, and on a Rev. 2 it's device 1. e.g.
i2cdetect -y 0 # Rev 1
i2cdetect -y 1 # Rev 2
Example of using the I2C Bus
// Register a device on the bus
var myDevice = Pi.I2C.AddDevice(0x20);
// Simple Write and Read (there are algo register read and write methods)
myDevice.Write(0x44);
var response = myDevice.Read();
// List registered devices on the I2C Bus
foreach (var device in Pi.I2C.Devices)
{
Console.WriteLine($"Registered I2C Device: {device.DeviceId}");
}TODO
Where is the serial port API? Well, it is something we will most likely add in the future. For now, you can simply use the built-in SerialPort class the .NET framework provides.