Publishing messages to target actuators in Swift
Whenever the user changes the value for the motorSwitch switch, we want to send a message to request the board to turn on or turn off the motor.
Click on Main.storyboard in the Project Navigator on the left-hand side of the Xcode window. The editor will switch to a design view that displays how the view will look. Click on View Controller under View Controller Scene, then click on View, and finally on Motor Switch.
Navigate to View | Assistant Editor | Show Assistant Editor in the Xcode menu or simply click on the button with two intersecting circles in the upper-right corner (the second button). Xcode will display the source code for the ViewController class on the right-hand side of the view preview for the main storyboard.
Right-click on Motor Switch and Xcode will display a popup that includes the sent events and the associated actions for this component, as shown in the next screenshot:
Click and drag the circle on the right-hand side of...
