let wheel = SMNumberWheel(frame: CGRect(x: 100, y: 100, width: 180, height: 180))
wheel.majorIndicators = 4
wheel.majorIndicatorType = .diamond
wheel.minorIndicatorType = .none
wheel.ringColor = UIColor.red
wheel.strokeColor = UIColor.red
wheel.stepper = false
wheel.hapticFeedback = true
// continue setting up the properties ...
wheel.delegate = self
self.view.addSubview(wheel)

extension viewController : SMNumberWheelDelegate {
    func SMNumberWheelDidResetToDefaultValue(_ numberWheel: SMNumberWheel) {
        // Happens when the central button is tapped and the wheel is set to it's initial value
    }
    func SMNumberWheelValueChanged(_ numberWheel: SMNumberWheel) {
        // Happens when the value of the wheel changes.
    }
    func SMNumberWheelReachedLimit(_ numberWheel: SMNumberWheel, stayedAtLimit: Bool) {
        // Notifies the developer that the value of the wheel has reached one of the limits.
    }
    func SMNumberWheelStepperKeyPressed(_ numberWheel: SMNumberWheel, rightKey: Bool) {
        // Notifies that a tap on one of the stepper keys is detected. 
        // rightKey == true -> tapped on right key, otherwise tapped on the left key.
    }
    func SMNumberWheelChangedAppearance(_ numberWheel: SMNumberWheel, minimized: Bool) {
        // Notifies the developer that the visual state of the wheel is changed (minimized or maximized).
    }
}