The relay is connected to our digital output pin 9 on the Arduino board. As such, controlling it is a simple call to the digitalWrite() method on our arduino object. Since we will need to perform this control action from various locations in code in later chapters, we'll create a method for it:
internal async Task SetOutput(bool On, string Actor)
{
if (this.arduino != null)
{
this.arduino.digitalWrite(9,
On ? PinState.HIGH : PinState.LOW); The first parameter simply states the new value of the control parameter. We'll add a second parameter that describes who is making the requested change. This will come in handy later, when we allow online users to change control parameters.