ReactiveGpio

ReactiveGpio is a .Net library for the control of GPIO pins on Linux utilising Reactive Extensions.

The current release supports GPIO input/output.

Input Port

An input port can be constructed using the static constructor method passing in the Gpio pin number, the edge to trigger on and optionally the driver to use.

var port = await InputPort.Create(22, GpioEdge.Both);

The value of the port can then be read via the Read() or ReadAsync() methods.

An input port is also an IObservable<bool> so it can also be observed using Reactive extensions.

var port = await InputPort.Create(22, GpioEdge.Both);

// Will write out to the console every time the edge stated is hit.
port.Subscribe(reading => Console.WriteLine("Reading: {0}", reading));

Output Port

Like the input port the output port is created with a static constructor method. It is created by passing in the pin number and optionally the initial value and driver.

var port = await OutputPort.Create(23);
// or
var port = await OutputPort.Create(23, OutputPort.InitialValue.Low);

The value of the port can then be set via the Write(value) or WriteAsync(value) methods.

The Output port is also an IObserver<bool> so it can observe an IObservable<bool> using Reactive extensions.

// Create observable that will generate an incrementing number every second
var observable = Observable.Generate(1, x => true, x => x + 1, x => x, x => TimeSpan.FromSeconds(1));

var port = await OutputPort.Create(23);

// Write true whenever the number is even and odd when the number is odd
observable.Select(x => x%2 == 0)
          .Subscribe(port)

Drivers

The ports take a driver class that controls how the port is read.

FileDriver

The file driver is the default driver, if no driver is specified it will be used. It uses the file based I/O to control the port.

This driver can be used as a non-root user.