diff --git a/XIONControlPanel/Controllers/MainViewController.swift b/XIONControlPanel/Controllers/MainViewController.swift
index fa5bb4a..2c7a836 100644
--- a/XIONControlPanel/Controllers/MainViewController.swift
+++ b/XIONControlPanel/Controllers/MainViewController.swift
@@ -8,7 +8,7 @@
 
 import UIKit
 
-class MainViewController: UIViewController {
+class MainViewController: UIViewController, SwitchesViewControllerDelegate {
     private var _visualizationController:   VisualizationViewController = VisualizationViewController()
     private var _switchesController:        SwitchesViewController = SwitchesViewController()
     private var _headerView:                HeaderView = HeaderView()
@@ -24,10 +24,18 @@ class MainViewController: UIViewController {
         self.addChildViewController(_visualizationController)
         self.view.addSubview(_visualizationController.view)
         
+        _switchesController.delegate = self
         self.addChildViewController(_switchesController)
         self.view.addSubview(_switchesController.view)
         
         self.view.addSubview(_headerView)
+        
+        // DEBUG
+        for _ in 0 ..< 10 {
+            let device = WemoDevice()
+            device.name = "beatmania IIDX"
+            self.devices.append(device)
+        }
     }
     
     override func viewDidLayoutSubviews()
@@ -81,4 +89,37 @@ class MainViewController: UIViewController {
     {
         return true
     }
+    
+    // MARK: API
+    
+    var devices: [WemoDevice] = []
+    {
+        didSet
+        {
+            _switchesController.devices = devices
+            _updateVisualization(false)
+        }
+    }
+    
+    // MARK: SwitchesViewControllerDelegate
+    
+    func switchesViewControllerDidToggleDevice(controller: SwitchesViewController, device: WemoDevice)
+    {
+        _updateVisualization(true)
+    }
+    
+    // MARK: Internal
+    
+    internal func _updateVisualization(animated: Bool)
+    {
+        var activatedDevicesCount = 0
+        for device in self.devices {
+            if (device.state == .On) {
+                ++activatedDevicesCount
+            }
+        }
+        
+        let percentageActivated = Float(activatedDevicesCount) / Float(self.devices.count)
+        _visualizationController.setPercentActivated(percentageActivated, animated: animated)
+    }
 }
diff --git a/XIONControlPanel/Controllers/SwitchesViewController.swift b/XIONControlPanel/Controllers/SwitchesViewController.swift
index 9361ea0..cb5c343 100644
--- a/XIONControlPanel/Controllers/SwitchesViewController.swift
+++ b/XIONControlPanel/Controllers/SwitchesViewController.swift
@@ -10,12 +10,23 @@ import Darwin
 import Foundation
 import UIKit
 
+protocol SwitchesViewControllerDelegate: class {
+    func switchesViewControllerDidToggleDevice(controller: SwitchesViewController, device: WemoDevice)
+}
+
+extension SwitchesViewControllerDelegate {
+    func switchesViewControllerDidToggleDevice(controller: SwitchesViewController, device: WemoDevice) {}
+}
+
 class SwitchesViewController: UIViewController,
                               UICollectionViewDataSource,
                               UICollectionViewDelegateFlowLayout
 {
-    private var _collectionView: UICollectionView = UICollectionView(frame: CGRectZero,
-                                                                     collectionViewLayout: UICollectionViewFlowLayout())
+    weak var delegate:           SwitchesViewControllerDelegate?
+    
+    private var _collectionView:        UICollectionView = UICollectionView(frame: CGRectZero,
+                                                                            collectionViewLayout: UICollectionViewFlowLayout())
+    private var _currentDevicesHash:    UInt = 0
     
     static private let collectionViewCellReuseIdentifier = "SwitchesCollectionViewReuseID"
     static private let collectionViewCellsSpacing: CGFloat = 5.0
@@ -46,11 +57,29 @@ class SwitchesViewController: UIViewController,
         _collectionView.frame = bounds
     }
     
+    // MARK: API
+    
+    var devices: [WemoDevice] = []
+    {
+        didSet
+        {
+            var devicesHash: UInt = 0
+            for device in devices {
+                devicesHash += UInt(device.serial.hash)
+            }
+            
+            if (_currentDevicesHash != devicesHash) {
+                _collectionView.reloadData()
+                _currentDevicesHash = devicesHash
+            }
+        }
+    }
+    
     // MARK: UICollectionView
     
     func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
     {
-        return 10
+        return self.devices.count
     }
     
     func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
@@ -58,10 +87,8 @@ class SwitchesViewController: UIViewController,
         let reuseID = SwitchesViewController.collectionViewCellReuseIdentifier
         let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseID, forIndexPath: indexPath) as! WemoDeviceCellView
         
-        var device = WemoDevice()
-        device.name = "beatmania IIDX"
+        let device = self.devices[indexPath.row]
         cell.device = device
-        
         cell.ordinal = indexPath.row + 1
         
         return cell
@@ -81,5 +108,10 @@ class SwitchesViewController: UIViewController,
     {
         let cell = collectionView.cellForItemAtIndexPath(indexPath) as! WemoDeviceCellView
         cell.toggled = !cell.toggled
+        
+        let device = self.devices[indexPath.row]
+        device.state = (cell.toggled ? .On : .Off)
+        
+        self.delegate?.switchesViewControllerDidToggleDevice(self, device: device)
     }
 }
diff --git a/XIONControlPanel/Models/WemoDevice.swift b/XIONControlPanel/Models/WemoDevice.swift
index 8a5239f..77194e8 100644
--- a/XIONControlPanel/Models/WemoDevice.swift
+++ b/XIONControlPanel/Models/WemoDevice.swift
@@ -8,7 +8,7 @@
 
 import Foundation
 
-struct WemoDevice {
+class WemoDevice {
     enum State {
         case Off
         case On
diff --git a/XIONControlPanel/Views/ConnectionStatusView.swift b/XIONControlPanel/Views/ConnectionStatusView.swift
index 07d44e7..2d17845 100644
--- a/XIONControlPanel/Views/ConnectionStatusView.swift
+++ b/XIONControlPanel/Views/ConnectionStatusView.swift
@@ -74,7 +74,8 @@ class ConnectionStatusView: UIView {
     
     // MARK: API
     
-    var connectivityStatus: Bool {
+    var connectivityStatus: Bool
+    {
         get
         {
             return _connectivityStatus
diff --git a/XIONControlPanel/Views/SwitchIndicatorView.swift b/XIONControlPanel/Views/SwitchIndicatorView.swift
index dbc3eee..726562e 100644
--- a/XIONControlPanel/Views/SwitchIndicatorView.swift
+++ b/XIONControlPanel/Views/SwitchIndicatorView.swift
@@ -74,7 +74,8 @@ class SwitchIndicatorView: UIView {
     
     // MARK: API
     
-    var status: Bool {
+    var status: Bool
+    {
         get
         {
             return _status
@@ -88,7 +89,8 @@ class SwitchIndicatorView: UIView {
         }
     }
     
-    var foregroundColor: UIColor {
+    var foregroundColor: UIColor
+    {
         get
         {
             return _foregroundColor
diff --git a/XIONControlPanel/Views/WemoDeviceCellView.swift b/XIONControlPanel/Views/WemoDeviceCellView.swift
index 38fa15c..2d3db4a 100644
--- a/XIONControlPanel/Views/WemoDeviceCellView.swift
+++ b/XIONControlPanel/Views/WemoDeviceCellView.swift
@@ -99,7 +99,8 @@ class WemoDeviceCellView: UICollectionViewCell {
 
     // MARK: API
     
-    var device: WemoDevice? {
+    var device: WemoDevice?
+    {
         get
         {
             return _device
@@ -112,7 +113,8 @@ class WemoDeviceCellView: UICollectionViewCell {
         }
     }
     
-    var ordinal: Int {
+    var ordinal: Int
+    {
         get
         {
             return _ordinal
@@ -125,7 +127,8 @@ class WemoDeviceCellView: UICollectionViewCell {
         }
     }
     
-    var toggled: Bool {
+    var toggled: Bool
+    {
         get
         {
             return (_device?.state == .On)