ProximitySensor.swift

func activateProximitySensor(isOn: Bool) {
        let device = UIDevice.current
        device.isProximityMonitoringEnabled = isOn
        if isOn {
            NotificationCenter.default.addObserver(self, selector: #selector(proximityStateDidChange), name: UIDevice.proximityStateDidChangeNotification, object: device)
            let session = AVAudioSession.sharedInstance()
            do{
                try session.setCategory(.playAndRecord)
                try session.setActive(true)
                try session.overrideOutputAudioPort(AVAudioSession.PortOverride.speaker)
            } catch {
                print ("\(#file) - \(#function) error: \(error.localizedDescription)")
            }
        } else {
            NotificationCenter.default.removeObserver(self, name: UIDevice.proximityStateDidChangeNotification, object: device)
        }
    }
    
    @objc func proximityStateDidChange(notification: NSNotification) {
        if let device = notification.object as? UIDevice {
            print(device)
            let session = AVAudioSession.sharedInstance()
            do{
                let routePort: AVAudioSessionPortDescription? = session.currentRoute.outputs.first
                let portType = routePort?.portType
                if let type = portType, type.rawValue == "Receiver" {
                    try session.overrideOutputAudioPort(AVAudioSession.PortOverride.speaker)
                } else {
                    try session.overrideOutputAudioPort(AVAudioSession.PortOverride.none)
                }
            } catch {
                print ("\(#file) - \(#function) error: \(error.localizedDescription)")
            }
        }
    }