From 0df1227908cc94dea17768f79081d0b80df034f8 Mon Sep 17 00:00:00 2001
From: Jonas Arnold <jonas.arnold@live.de>
Date: Thu, 22 Dec 2022 22:01:13 +0100
Subject: [PATCH] updated UI, redesigned, implemented state indicators for
 robot mobile and stationary

---
 ADIS_Csharp/RobotClientWpf/MainWindow.xaml    |  45 ++++--
 ADIS_Csharp/RobotClientWpf/MainWindow.xaml.cs |  41 ++++-
 .../Utilities/UIAccessHelpers.cs              |   6 +-
 .../RobotClientWpf/Views/ConfigView.xaml      |   2 +-
 .../RobotClientWpf/Views/MainView.xaml        | 144 +++++++++---------
 .../RobotClientWpf/Views/MainView.xaml.cs     |  15 --
 ADIS_Csharp/RobotLib/Battery/DevBattery.cs    |  40 +++--
 .../Battery/LastResponseUpdateEventArgs.cs    |  24 +++
 ADIS_Csharp/RobotLib/Robot.cs                 |  36 ++---
 9 files changed, 211 insertions(+), 142 deletions(-)
 create mode 100644 ADIS_Csharp/RobotLib/Battery/LastResponseUpdateEventArgs.cs

diff --git a/ADIS_Csharp/RobotClientWpf/MainWindow.xaml b/ADIS_Csharp/RobotClientWpf/MainWindow.xaml
index 8070122..ae999e5 100644
--- a/ADIS_Csharp/RobotClientWpf/MainWindow.xaml
+++ b/ADIS_Csharp/RobotClientWpf/MainWindow.xaml
@@ -12,16 +12,38 @@
         <Grid.RowDefinitions>
             <RowDefinition Height="40"/>
             <RowDefinition Height="*"/>
-            <RowDefinition Height="200"/>
-            <RowDefinition Height="30"/>
+            <RowDefinition Height="260"/>
+            <!-- <RowDefinition Height="30"/>  Bottom message (NOT USED) -->
         </Grid.RowDefinitions>
 
-        <StackPanel Grid.Row="0" Orientation="Horizontal" Margin="5,5,5,5" Grid.ColumnSpan="2">
-            <Label HorizontalAlignment="Center">MQTT Broker IP:</Label>
-            <TextBox x:Name="tbIp" Width="120" Height="25" FontSize="15" TextAlignment="Left" Margin="10 0 0 0">192.168.156.156</TextBox>
-            <Button x:Name="btnConnectDisconnect" Content="Connect" Width="100" Margin="20 0 0 0" Click="btnConnectDisconnect_Click"></Button>
-        </StackPanel>
+        <!-- ROW 0: Broker IP and states-->
+        <Grid Grid.Row="0">
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="400"/>
+                <ColumnDefinition Width="*"/>
+            </Grid.ColumnDefinitions>
 
+            <StackPanel Grid.Row="0" Grid.Column="0" Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Left" Margin="5">
+                <Label FontWeight="Bold">MQTT Broker IP:</Label>
+                <TextBox x:Name="tbIp" Width="120" Height="25" FontSize="15" TextAlignment="Left" Margin="10 0 0 0">192.168.156.156</TextBox>
+                <Button x:Name="btnConnectDisconnect" Content="Connect" Width="100" Margin="20 0 0 0" Click="btnConnectDisconnect_Click"></Button>
+            </StackPanel>
+
+            <StackPanel Grid.Row="0" Grid.Column="1" Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Right">
+                <Label FontWeight="Bold">Robot states:</Label>
+                <StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
+                    <Label Content="Robot Mobile:" Margin="5 0 0 0"/>
+                    <Ellipse Fill="Gray" x:Name="elRobotMobileIndicator" Width="20" Height="20" Margin="15 0" Opacity="100"/>
+                </StackPanel>
+
+                <StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
+                    <Label Content="Robot Stationary:" Margin="5 0 0 0"/>
+                    <Ellipse Fill="Gray" x:Name="elRobotStationaryIndicator" Width="20" Height="20" Margin="15 0" Opacity="100"/>
+                </StackPanel>
+            </StackPanel>
+        </Grid>
+
+        <!-- ROW 1: Tab control -->
         <TabControl Grid.Row="1" x:Name="tabControlMain" Grid.ColumnSpan="2">
             <TabControl.ItemContainerStyle>
                 <Style TargetType="{x:Type TabItem}">
@@ -48,6 +70,7 @@
             </TabItem>
         </TabControl>
 
+        <!-- ROW 2: NLOG viewer -->
         <dj:NLogViewer Grid.Row="2" Margin="5" DebugForeground="Black" MaxCount="150" ErrorForeground="Black" FatalForeground="Black" TraceForeground="Black" InfoForeground="Black" WarnForeground="Black" >
             <dj:NLogViewer.WarnBackground>
                 <SolidColorBrush Color="#FFFF9D00" Opacity="0.5"/>
@@ -68,12 +91,10 @@
                 <SolidColorBrush Color="Red" Opacity="0.5"/>
             </dj:NLogViewer.FatalBackground>
         </dj:NLogViewer>
-        <!--<RichTextBox x:Name="rtbLogs" Grid.Row="2" Margin="10 0 10 0" IsReadOnly="True">
-            
-        </RichTextBox>-->
 
-        <StackPanel Grid.Row="3" Orientation="Horizontal" Margin="0,150,0,0">
+        <!-- ROW 3: Bottom message (NOT USED) -->
+        <!--<StackPanel Grid.Row="3" Orientation="Horizontal" Margin="0,150,0,0">
             <TextBlock x:Name="tbBottomMessage" FontSize="15" Margin="10 5"/>
-        </StackPanel>
+        </StackPanel>-->
     </Grid>
 </Window>
diff --git a/ADIS_Csharp/RobotClientWpf/MainWindow.xaml.cs b/ADIS_Csharp/RobotClientWpf/MainWindow.xaml.cs
index 8645934..d01fac1 100644
--- a/ADIS_Csharp/RobotClientWpf/MainWindow.xaml.cs
+++ b/ADIS_Csharp/RobotClientWpf/MainWindow.xaml.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Net;
+using System.Text.Json.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows;
@@ -22,6 +23,9 @@ namespace RobotClientWpf
         private static readonly NLog.Logger log = NLog.LogManager.GetCurrentClassLogger();
         private ChallengeFactory challenge;
         private bool manualDisconnect;
+        private Brush onlineBrush = Brushes.Green;
+        private Brush offlineBrush = Brushes.Red;
+        private Brush unknownBrush = Brushes.Gray;
 
         public MainWindow()
         {
@@ -48,12 +52,44 @@ namespace RobotClientWpf
             this.configView.InitializeChildView(this.challenge, this);
             // subscribe to events
             this.challenge.PublisherSubscriber.ConnectionStateChanged += PublisherSubscriber_ConnectionStateChanged;
+            this.challenge.RobotMobile.Battery.LastResponseUpdate += RobotMobile_Battery_SecondsSinceLastResponseUpdate;
+            this.challenge.RobotStationary.Battery.LastResponseUpdate += RobotStationary_Battery_SecondsSinceLastResponseUpdate;
+        }
+
+        private void RobotStationary_Battery_SecondsSinceLastResponseUpdate(object? sender, LastResponseUpdateEventArgs e)
+        {
+            // set color according to assessed state
+            if(e.Online == false)
+            {
+                log.Warn("Robot Stationary seems to be offline.");
+            }
+            else
+            {
+                log.Info("Robot Stationary is online.");
+            }
+            UIAccessHelpers.SetShapeFillColor(elRobotStationaryIndicator, e.Online ? onlineBrush : offlineBrush);
+        }
+
+        private void RobotMobile_Battery_SecondsSinceLastResponseUpdate(object? sender, LastResponseUpdateEventArgs e)
+        {
+            // set color according to assessed state
+            if (e.Online == false)
+            {
+                log.Warn("Robot Mobile seems to be offline.");
+            }
+            else
+            {
+                log.Info("Robot Mobile is online.");
+            }
+            UIAccessHelpers.SetShapeFillColor(elRobotMobileIndicator, e.Online ? onlineBrush : offlineBrush);
         }
 
         private void PublisherSubscriber_ConnectionStateChanged(object? sender, bool e)
         {
             if(e == false)
             {
+                UIAccessHelpers.SetShapeFillColor(elRobotMobileIndicator, unknownBrush);
+                UIAccessHelpers.SetShapeFillColor(elRobotStationaryIndicator, unknownBrush);
                 if (manualDisconnect == true)
                 {
                     manualDisconnect = false;
@@ -77,11 +113,6 @@ namespace RobotClientWpf
             }
         }
 
-        private void buttonBuzz_Click(object sender, RoutedEventArgs e)
-        {
-            //Robot.Instance.Buzzer.Beep(300, 500);
-        }
-
         private void btnConnectDisconnect_Click(object sender, RoutedEventArgs e)
         {
             Task.Run(delegate ()
diff --git a/ADIS_Csharp/RobotClientWpf/Utilities/UIAccessHelpers.cs b/ADIS_Csharp/RobotClientWpf/Utilities/UIAccessHelpers.cs
index 3ab21d9..be5a642 100644
--- a/ADIS_Csharp/RobotClientWpf/Utilities/UIAccessHelpers.cs
+++ b/ADIS_Csharp/RobotClientWpf/Utilities/UIAccessHelpers.cs
@@ -101,18 +101,18 @@ namespace RobotClientWpf.Utilities
             }
         }
 
-        public static void SetShapeVisibility(Shape shape, bool visible)
+        public static void SetShapeFillColor(Shape shape, Brush color)
         {
             if (!Application.Current.Dispatcher.CheckAccess())
             {
                 Application.Current.Dispatcher.BeginInvoke(new Action(() =>
                 {
-                    SetShapeVisibility(shape, visible);
+                    SetShapeFillColor(shape, color);
                 }));
             }
             else
             {
-                shape.Opacity = visible?100:0;
+                shape.Fill = color;
             }
         }
     }
diff --git a/ADIS_Csharp/RobotClientWpf/Views/ConfigView.xaml b/ADIS_Csharp/RobotClientWpf/Views/ConfigView.xaml
index f5c20be..f78b9c0 100644
--- a/ADIS_Csharp/RobotClientWpf/Views/ConfigView.xaml
+++ b/ADIS_Csharp/RobotClientWpf/Views/ConfigView.xaml
@@ -33,7 +33,7 @@
                         <Button x:Name="btnApplyConfiguration" Content="Apply" HorizontalAlignment="Right" Height="30" Width="100" Margin="10" Click="btnApplyConfiguration_Click"/>
                     </DockPanel>
                 </GroupBox>
-                <GroupBox Header="Move to zero position">
+                <GroupBox Header="Initialization">
                     <DockPanel>
                         <Button x:Name="btnInitSplitflaps" Content="Move to Zero" HorizontalAlignment="Left" Height="30" Width="100" Margin="10" Click="btnInitSplitflaps_Click"/>
                     </DockPanel>
diff --git a/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml b/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml
index 76fa90b..1aa0a06 100644
--- a/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml
+++ b/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml
@@ -12,88 +12,88 @@
             <ColumnDefinition Width="400"/>
         </Grid.ColumnDefinitions>
         <Grid.RowDefinitions>
-            <RowDefinition Height="200"/>
+            <RowDefinition Height="300"/>
             <RowDefinition Height="*"/>
         </Grid.RowDefinitions>
 
         <!-- RIGHT SIDE -->
         <StackPanel Orientation="Vertical" Grid.Row="0" Grid.Column="1" Grid.RowSpan="2">
-            <GroupBox Header="Splitflap Display" Margin="10" HorizontalAlignment="Right" Width="180">
-                <TextBox x:Name="tbSplitflapText" Height="70" Width="150" FontSize="30" IsReadOnly="True" TextWrapping="NoWrap" HorizontalAlignment="Left"/>
-            </GroupBox>
-            <GroupBox Header="Robot" Margin="10" HorizontalAlignment="Right" Width="350">
-                <StackPanel Orientation="Vertical">
-                    <StackPanel Orientation="Horizontal">
-                        <Label Content="Battery" Margin="10 0"/>
-                        <TextBox x:Name="tbRoboVoltage" Height="25" Width="100" FontSize="15" IsReadOnly="True" TextWrapping="NoWrap" HorizontalAlignment="Left">NaN</TextBox>
-                        <Label Content="V" Margin="10 0"/>
-                    </StackPanel>
-                    <StackPanel Orientation="Horizontal">
-                        <Label Content="State" Margin="10 0"/>
-                        <Ellipse Fill="Red" x:Name="ellipseRed" Width="20" Height="20" Margin="15 0" Opacity="0"/>
-                        <Ellipse Fill="Green" x:Name="ellipseGreen" Width="20" Height="20" Margin="0 0" Opacity="0"/>
-                    </StackPanel>
-
-                </StackPanel>
+            <GroupBox Header="Splitflap Display" Margin="10" HorizontalAlignment="Right">
+                <TextBox x:Name="tbSplitflapText" Height="100" Width="300" FontSize="40" IsReadOnly="True" TextWrapping="NoWrap" HorizontalAlignment="Left"/>
             </GroupBox>
         </StackPanel>
 
         <!-- LEFT SIDE -->
-        <DockPanel>
-            <GroupBox DockPanel.Dock="Left" Grid.Column="0" Header="Robot Control" Width="200">
-                <StackPanel Orientation="Vertical" Margin="5">
-                    <Button x:Name="btnModeAuto" Height="25" Margin="0 5" Click="btnModeAuto_Click">Set Automatic Mode</Button>
-                    <Button x:Name="btnModeManual" Height="25" Margin="0 5" Click="btnModeManual_Click">Set Manual Mode</Button>
-                </StackPanel>
-            </GroupBox>
-            <GroupBox DockPanel.Dock="Left" Grid.Column="0" Header="Robot Steering" Width="200">
-                <Grid>
-                    <Grid.ColumnDefinitions>
-                        <ColumnDefinition Width="*"/>
-                        <ColumnDefinition Width="*"/>
-                        <ColumnDefinition Width="*"/>
-                    </Grid.ColumnDefinitions>
-                    <Grid.RowDefinitions>
-                        <RowDefinition Height="*"/>
-                        <RowDefinition Height="*"/>
-                        <RowDefinition Height="*"/>
-                        <RowDefinition Height="25"/>
-                        <RowDefinition Height="25"/>
-                    </Grid.RowDefinitions>
+        <StackPanel Orientation="Horizontal">
+            <GroupBox Header="Robot Mobile">
+                <StackPanel Orientation="Horizontal">
+                    <StackPanel Orientation="Vertical">
+                        <GroupBox Header="State">
+                            <StackPanel Orientation="Vertical">
+                                <Label Content="Battery:"/>
+                                <StackPanel Orientation="Horizontal">
+                                    <TextBox x:Name="tbRoboVoltage" Margin="10 0 0 0" Width="100px" Height="30" FontSize="20" IsReadOnly="True" TextWrapping="NoWrap" HorizontalAlignment="Left">NaN</TextBox>
+                                    <Label Content="V" FontSize="20"/>
+                                </StackPanel>
+                            </StackPanel>
+                        </GroupBox>
+                        <GroupBox Grid.Column="0" Header="Control" Width="200">
+                            <StackPanel Orientation="Vertical" Margin="5">
+                                <Button x:Name="btnModeAuto" Height="30" Margin="5 5" Click="btnModeAuto_Click">Set Automatic Mode</Button>
+                                <Button x:Name="btnModeManual" Height="30" Margin="5 5" Click="btnModeManual_Click">Set Manual Mode</Button>
+                            </StackPanel>
+                        </GroupBox>
+                    </StackPanel>
+                    <GroupBox Grid.Column="0" Header="Steering" Width="200">
+                        <Grid>
+                            <Grid.ColumnDefinitions>
+                                <ColumnDefinition Width="*"/>
+                                <ColumnDefinition Width="*"/>
+                                <ColumnDefinition Width="*"/>
+                            </Grid.ColumnDefinitions>
+                            <Grid.RowDefinitions>
+                                <RowDefinition Height="*"/>
+                                <RowDefinition Height="*"/>
+                                <RowDefinition Height="*"/>
+                                <RowDefinition Height="25"/>
+                                <RowDefinition Height="25"/>
+                            </Grid.RowDefinitions>
 
-                    <Button Grid.Column="1" Grid.Row="0" Height="30" Width="30" x:Name="btnRoboFwd" Click="btnRoboFwd_Click">
-                        <Image>
-                            <Image.Source>
-                                <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate180"/>
-                            </Image.Source>
-                        </Image> 
-                    </Button>
-                    <Button Grid.Column="1" Grid.Row="1" Height="30" Width="30" x:Name="btnRoboBwd" Click="btnRoboBwd_Click">
-                        <Image>
-                            <Image.Source>
-                                <BitmapImage UriSource="/Assets/arrow-down-bold.png"/>
-                            </Image.Source>
-                        </Image>
-                    </Button>
-                    <Button Grid.Column="0" Grid.Row="1"  Height="30" Width="30" x:Name="btnRoboLeft" Click="btnRoboLeft_Click">
-                        <Image>
-                            <Image.Source>
-                                <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate90"/>
-                            </Image.Source>
-                        </Image>
-                    </Button>
-                    <Button Grid.Column="2" Grid.Row="1" Height="30" Width="30" x:Name="btnRoboRight" Click="btnRoboRight_Click">
-                        <Image>
-                            <Image.Source>
-                                <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate270"/>
-                            </Image.Source>
-                        </Image>
-                    </Button>
-                    <Button Grid.Row="2" Grid.ColumnSpan="3" x:Name="btnStopMove" Content="Stop" Margin="5" Click="btnStopMove_Click"/>
-                    <Label Grid.Row="3" Grid.ColumnSpan="3" FontWeight="Bold" FontSize="12" Margin="5 0">Control with Arrow keys</Label>
-                    <Label Grid.Row="4" Grid.ColumnSpan="3" FontWeight="Bold" FontSize="12" Margin="5 0">Stop with End key</Label>
-                </Grid>
+                            <Button Grid.Column="1" Grid.Row="0" Height="50" Width="50" x:Name="btnRoboFwd" Click="btnRoboFwd_Click">
+                                <Image>
+                                    <Image.Source>
+                                        <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate180"/>
+                                    </Image.Source>
+                                </Image>
+                            </Button>
+                            <Button Grid.Column="1" Grid.Row="1" Height="50" Width="50" x:Name="btnRoboBwd" Click="btnRoboBwd_Click">
+                                <Image>
+                                    <Image.Source>
+                                        <BitmapImage UriSource="/Assets/arrow-down-bold.png"/>
+                                    </Image.Source>
+                                </Image>
+                            </Button>
+                            <Button Grid.Column="0" Grid.Row="1"  Height="50" Width="50" x:Name="btnRoboLeft" Click="btnRoboLeft_Click">
+                                <Image>
+                                    <Image.Source>
+                                        <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate90"/>
+                                    </Image.Source>
+                                </Image>
+                            </Button>
+                            <Button Grid.Column="2" Grid.Row="1" Height="50" Width="50" x:Name="btnRoboRight" Click="btnRoboRight_Click">
+                                <Image>
+                                    <Image.Source>
+                                        <BitmapImage UriSource="/Assets/arrow-down-bold.png" Rotation="Rotate270"/>
+                                    </Image.Source>
+                                </Image>
+                            </Button>
+                            <Button Grid.Row="2" Grid.ColumnSpan="3" x:Name="btnStopMove" Content="Stop" Margin="5" Click="btnStopMove_Click"/>
+                            <Label Grid.Row="3" Grid.ColumnSpan="3" FontWeight="Bold" FontSize="12" Margin="5 0">Control with Arrow keys</Label>
+                            <Label Grid.Row="4" Grid.ColumnSpan="3" FontWeight="Bold" FontSize="12" Margin="5 0">Stop with End key</Label>
+                        </Grid>
+                    </GroupBox>
+                </StackPanel>
             </GroupBox>
-        </DockPanel>
+        </StackPanel>
     </Grid>
 </UserControl>
diff --git a/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml.cs b/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml.cs
index 7342bfd..97d125c 100644
--- a/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml.cs
+++ b/ADIS_Csharp/RobotClientWpf/Views/MainView.xaml.cs
@@ -27,21 +27,6 @@ namespace RobotClientWpf.Views
             // subscribe to events
             this.challenge.RobotStationary.SplitFlap.SplitFlapDisplayChanged += this.SplitFlap_SplitFlapDisplayChanged;
             this.challenge.RobotMobile.Battery.BatteryChanged += Battery_BatteryChanged;
-            this.challenge.RobotMobile.Battery.SecondsSinceLastResponseUpdate += Battery_SecondsSinceLastResponseUpdate;
-        }
-
-        private void Battery_SecondsSinceLastResponseUpdate(object? sender, int e)
-        {
-            if(e > 15)
-            {
-                UIAccessHelpers.SetShapeVisibility(ellipseRed, true);
-                UIAccessHelpers.SetShapeVisibility(ellipseGreen, false);
-            }
-            else
-            {
-                UIAccessHelpers.SetShapeVisibility(ellipseRed, false);
-                UIAccessHelpers.SetShapeVisibility(ellipseGreen, true);
-            }
         }
 
         private void Battery_BatteryChanged(object? sender, RobotLib.Battery.BatteryEventArgs e)
diff --git a/ADIS_Csharp/RobotLib/Battery/DevBattery.cs b/ADIS_Csharp/RobotLib/Battery/DevBattery.cs
index 171c768..abe7907 100644
--- a/ADIS_Csharp/RobotLib/Battery/DevBattery.cs
+++ b/ADIS_Csharp/RobotLib/Battery/DevBattery.cs
@@ -3,13 +3,15 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text.Json;
+using System.Threading.Tasks;
 
 namespace RobotLib.Battery
 {
     public class DevBattery : DevBase
     {
         private float voltage;
-        private int secondsSinceLastResponse = 0;
+        private int lastResponseS = 1000;  // seconds since last response
+        private const int offlineTresholdS = 11;   // treshold when to assess a robot as offline (no response for x sec)
         private Stopwatch stopwatchLastResponse = new();
 
         private const string TOPIC_ROBO_REQ_BATTERY = "/both/cmd/battery/get_volt";
@@ -17,7 +19,7 @@ namespace RobotLib.Battery
         private const string TOPIC_STAT_RESP_BATTERY = "/stationary/state/battery/voltage";
 
         public event EventHandler<BatteryEventArgs> BatteryChanged;
-        public event EventHandler<int> SecondsSinceLastResponseUpdate;
+        public event EventHandler<LastResponseUpdateEventArgs> LastResponseUpdate;
 
         public float Voltage
         {
@@ -36,11 +38,22 @@ namespace RobotLib.Battery
 
         public int SecondsSinceLastResponse
         {
-            get { return secondsSinceLastResponse; }
+            get { return lastResponseS; }
             private set
             {
-                secondsSinceLastResponse = value;
-                SecondsSinceLastResponseUpdate?.Invoke(this, secondsSinceLastResponse);
+                var lastVal = lastResponseS; // last stored value
+                lastResponseS = value;   // update stored value
+                // new value is smaller than online time and old value is larger or equal => newly connected
+                if (value < offlineTresholdS && lastVal >= offlineTresholdS) 
+                {
+                    LastResponseUpdate?.Invoke(this, new LastResponseUpdateEventArgs(true, value));
+                }
+                // old value is larger than online time and new value is smaller => newly disconnected
+                else if(value >= offlineTresholdS && lastVal < offlineTresholdS)
+                {
+                    Task.Run(() => this.Voltage = float.NaN);  // set voltage to NaN, now unknown
+                    LastResponseUpdate?.Invoke(this, new LastResponseUpdateEventArgs(false, value));
+                }
             }
         }
 
@@ -57,22 +70,27 @@ namespace RobotLib.Battery
                 return new List<string>() { TOPIC_ROBO_RESP_BATTERY };
             }
         }
-        public void RequestBatteryVoltage()
+
+        public void UpdateLastResponse()
         {
-            base.SendMessage(TOPIC_ROBO_REQ_BATTERY, true.ToString());
             if (this.stopwatchLastResponse.IsRunning)
             {
-                SecondsSinceLastResponse = this.stopwatchLastResponse.Elapsed.Seconds;
+                this.SecondsSinceLastResponse = this.stopwatchLastResponse.Elapsed.Seconds;
             }
         }
 
+        public void RequestBatteryVoltage()
+        {
+            base.SendMessage(TOPIC_ROBO_REQ_BATTERY, true.ToString());
+            this.UpdateLastResponse();
+        }
+
         protected override void ParseMessage(string fromTopic, string message)
         {
             if (fromTopic == TOPIC_ROBO_RESP_BATTERY || fromTopic == TOPIC_STAT_RESP_BATTERY)
             {
-                this.stopwatchLastResponse.Stop();
-                this.stopwatchLastResponse.Start();
-                SecondsSinceLastResponse = 0;
+                this.stopwatchLastResponse.Restart();
+                this.SecondsSinceLastResponse = 0;
 
                 var parsedString = GetValueFromMesage<string>("voltage", message);
                 if (parsedString == null) parsedString = "?";
diff --git a/ADIS_Csharp/RobotLib/Battery/LastResponseUpdateEventArgs.cs b/ADIS_Csharp/RobotLib/Battery/LastResponseUpdateEventArgs.cs
new file mode 100644
index 0000000..1946248
--- /dev/null
+++ b/ADIS_Csharp/RobotLib/Battery/LastResponseUpdateEventArgs.cs
@@ -0,0 +1,24 @@
+using System;
+
+namespace RobotLib.Battery
+{
+    public class LastResponseUpdateEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Seconds since last got a response from the robot.
+        /// </summary>
+        public int Seconds { get; }
+
+        /// <summary>
+        /// Returns true if the robot is assessed to be online.
+        /// Returns false if the robot was unresonsive for too long.
+        /// </summary>
+        public bool Online { get; }
+
+        public LastResponseUpdateEventArgs(bool connected, int seconds)
+        {
+            Seconds = seconds;
+            Online = connected;
+        }
+    }
+}
diff --git a/ADIS_Csharp/RobotLib/Robot.cs b/ADIS_Csharp/RobotLib/Robot.cs
index 68dfe07..b34b821 100644
--- a/ADIS_Csharp/RobotLib/Robot.cs
+++ b/ADIS_Csharp/RobotLib/Robot.cs
@@ -9,6 +9,16 @@ namespace RobotLib
 {
     public class Robot
     {
+        public IPublisherSubscriber Com { get; }
+        public RobotMode Mode { get; }
+
+        //public DevBuzzer Buzzer { get; }
+        public DevBattery Battery { get; }
+        public DevSplitFlap SplitFlap { get; }
+        public DevMovement Movement { get; }
+        public DevLineSensor LineSensor { get; }
+        public DevStatus Status { get; }
+
         public Robot(IPublisherSubscriber com, RobotMode mode)
         {
             Com = com;
@@ -35,38 +45,18 @@ namespace RobotLib
 
             Timer timer = new Timer
             {
-                Interval = 15000
+                Interval = 1000
             };
             timer.Enabled= true;
             timer.Elapsed += Timer_Elapsed;
         }
 
-        public IPublisherSubscriber Com { get; }
-        public RobotMode Mode { get; }
-
-        //public DevBuzzer Buzzer { get; }
-        public DevBattery Battery { get; }
-        public DevSplitFlap SplitFlap { get; }
-        public DevMovement Movement { get; }
-        public DevLineSensor LineSensor { get; }
-
-        public DevStatus Status { get; }
-
-        public void Connect(string host, int port)
-        {
-            //Com.Connect(host, port);
-        }
-
-        public void Disconnect()
-        {
-            //Com.Disconnect();
-        }
-
         private void Timer_Elapsed(object sender, ElapsedEventArgs e)
         {
             if (Com.IsConnected)
             {
-                //Battery?.RequestBatteryVoltage();
+                Battery?.UpdateLastResponse();
+                //Battery?.RequestBatteryVoltage();  // is automatically sent by robot
             }
         }
     }