diff --git a/app/src/main/java/com/example/medilightv2android/AppState.kt b/app/src/main/java/com/example/medilightv2android/AppState.kt
index a4f4189..8ecd0c6 100644
--- a/app/src/main/java/com/example/medilightv2android/AppState.kt
+++ b/app/src/main/java/com/example/medilightv2android/AppState.kt
@@ -22,6 +22,7 @@ class AppState(private val context: Context) {
     var sensorMode by mutableStateOf(SensorMode.PIEZO)
     var bladderLevel by mutableStateOf(BladderLevel())
     var isDeviceConnected by mutableStateOf(false)
+    var isDemoMode by mutableStateOf(false)
     var piezoSettings by mutableStateOf(PiezoSettings())
     var catheterCount = mutableIntStateOf(0)
 
@@ -66,11 +67,22 @@ class AppState(private val context: Context) {
     fun goHome() {
         NirsManager.instance.stopStreaming()
         NirsManager.instance.reset()
-        bleManager.disconnect()
+        if (!isDemoMode) bleManager.disconnect()
         isDeviceConnected = false
+        isDemoMode = false
         currentScreen = AppScreen.HOME
     }
 
+    fun enterDemoMode() {
+        isDemoMode = true
+        isDeviceConnected = true
+        currentScreen = if (sensorMode == SensorMode.NIRS) {
+            AppScreen.VIVAMYO_MONITORING
+        } else {
+            AppScreen.PIEZO_MONITORING
+        }
+    }
+
     fun startFromHome() {
         currentScreen = AppScreen.SENSOR_SELECT
     }
diff --git a/app/src/main/java/com/example/medilightv2android/ui/views/connection/DeviceScanView.kt b/app/src/main/java/com/example/medilightv2android/ui/views/connection/DeviceScanView.kt
index 663fcdd..7009d06 100644
--- a/app/src/main/java/com/example/medilightv2android/ui/views/connection/DeviceScanView.kt
+++ b/app/src/main/java/com/example/medilightv2android/ui/views/connection/DeviceScanView.kt
@@ -251,6 +251,16 @@ fun DeviceScanView(appState: AppState) {
             }
         }
 
+        // Demo mode button
+        TextButton(
+            onClick = { appState.enterDemoMode() },
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 24.dp)
+        ) {
+            Text("Demo Mode (No Device)", fontSize = 14.sp, color = MlSecondaryText)
+        }
+
         // Scan button
         Button(
             onClick = {
diff --git a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
index 768669e..f79cb4d 100644
--- a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
+++ b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt
@@ -48,6 +48,7 @@ fun PiezoMonitoringView(appState: AppState) {
     var reconnectionState by remember { mutableStateOf(BleReconnectionState.DISCONNECTED) }
     var isAutoMeasuring by remember { mutableStateOf(false) }
 
+    val isDemoMode = appState.isDemoMode
     val urgency = appState.bladderLevel.urgency
     val batteryLvl by bleManager.batteryLevel
     val isConnected by bleManager.isConnected
@@ -179,13 +180,18 @@ fun PiezoMonitoringView(appState: AppState) {
             }
 
             // Battery
-            Text("$batteryLvl%", fontSize = 13.sp, color = MlSecondaryText)
+            if (isDemoMode) {
+                Text("DEMO", fontSize = 11.sp, fontWeight = FontWeight.Bold, color = Color.White,
+                    modifier = Modifier.clip(RoundedCornerShape(4.dp)).background(Color(0xFFFF9500)).padding(horizontal = 6.dp, vertical = 2.dp))
+            } else {
+                Text("$batteryLvl%", fontSize = 13.sp, color = MlSecondaryText)
+            }
             Spacer(modifier = Modifier.width(4.dp))
             Box(
                 modifier = Modifier
                     .size(10.dp)
                     .clip(CircleShape)
-                    .background(if (isConnected) Color.Green else Color.Red)
+                    .background(if (isDemoMode || isConnected) Color.Green else Color.Red)
             )
         }
 
diff --git a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/VivamyoMonitoringView.kt b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/VivamyoMonitoringView.kt
index 75ffb71..6dcd5df 100644
--- a/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/VivamyoMonitoringView.kt
+++ b/app/src/main/java/com/example/medilightv2android/ui/views/monitoring/VivamyoMonitoringView.kt
@@ -31,10 +31,12 @@ import com.example.medilightv2android.AppState
 import com.example.medilightv2android.ble.BleManager
 import com.example.medilightv2android.managers.NirsManager
 import com.example.medilightv2android.models.NirsMcjPacket
+import com.example.medilightv2android.models.NirsOxyResult
 import com.example.medilightv2android.ui.components.BladdyIdleRiveView
 import com.example.medilightv2android.ui.components.BleDisconnectionBanner
 import com.example.medilightv2android.ui.components.BleReconnectionState
 import com.example.medilightv2android.ui.theme.*
+import kotlin.random.Random
 
 @Composable
 fun VivamyoMonitoringView(appState: AppState) {
@@ -56,6 +58,11 @@ fun VivamyoMonitoringView(appState: AppState) {
     val sampleCount by nirsManager.sampleCount
     val isFilterEnabled by nirsManager.isFilterEnabled
 
+    val isDemoMode = appState.isDemoMode
+    var demoRunnable by remember { mutableStateOf<Runnable?>(null) }
+    var demoBaseHbO2 by remember { mutableStateOf(12.0) }
+    var demoBaseHb by remember { mutableStateOf(8.0) }
+
     var mcjRetryCount = remember { mutableIntStateOf(0) }
     var mcjRetryRunnable by remember { mutableStateOf<Runnable?>(null) }
 
@@ -108,6 +115,39 @@ fun VivamyoMonitoringView(appState: AppState) {
         handler.postDelayed(initialRetry, 2000)
     }
 
+    fun startDemoStream() {
+        val tick = object : Runnable {
+            override fun run() {
+                if (!nirsManager.isStreaming.value) return
+                demoBaseHbO2 += Random.nextDouble(-0.3, 0.3)
+                demoBaseHb += Random.nextDouble(-0.2, 0.2)
+                val hbO2 = demoBaseHbO2.coerceIn(5.0, 25.0)
+                val hb = demoBaseHb.coerceIn(3.0, 15.0)
+                demoBaseHbO2 = hbO2
+                demoBaseHb = hb
+                val tHb = hbO2 + hb
+                val stO2 = if (tHb > 0) (hbO2 / tHb * 100.0) else 0.0
+
+                nirsManager.currentOxy.value = NirsOxyResult(hbO2, hb, tHb, stO2)
+                nirsManager.sampleCount.intValue++
+                nirsManager.oxyHbO2History.add(hbO2)
+                nirsManager.oxyHbHistory.add(hb)
+                if (nirsManager.oxyHbO2History.size > 240) nirsManager.oxyHbO2History.removeAt(0)
+                if (nirsManager.oxyHbHistory.size > 240) nirsManager.oxyHbHistory.removeAt(0)
+
+                handler.postDelayed(this, 250)
+            }
+        }
+        demoRunnable = tick
+        handler.post(tick)
+    }
+
+    fun stopDemoStream() {
+        demoRunnable?.let { handler.removeCallbacks(it) }
+        demoRunnable = null
+        nirsManager.stopStreaming()
+    }
+
     fun stopNirsStream() {
         // 1. Stop polling chain & clear callback first
         nirsManager.stopStreaming()
@@ -124,11 +164,16 @@ fun VivamyoMonitoringView(appState: AppState) {
         if (isToggling) return
         isToggling = true
         if (isStreaming) {
-            stopNirsStream()
+            if (isDemoMode) stopDemoStream() else stopNirsStream()
         } else {
-            bleManager.stopBatteryPolling() // Pause battery polling during streaming
-            nirsManager.startStreaming()
-            startNirsStream()
+            if (isDemoMode) {
+                nirsManager.startStreaming()
+                startDemoStream()
+            } else {
+                bleManager.stopBatteryPolling()
+                nirsManager.startStreaming()
+                startNirsStream()
+            }
         }
         handler.postDelayed({ isToggling = false }, 1000)
     }
@@ -141,7 +186,8 @@ fun VivamyoMonitoringView(appState: AppState) {
     }
 
     DisposableEffect(Unit) { onDispose {
-        if (nirsManager.isStreaming.value) stopNirsStream()
+        if (isDemoMode) { stopDemoStream() }
+        else if (nirsManager.isStreaming.value) stopNirsStream()
         else { cancelMcjRetry(); bleManager.onNirsMcjReceived = null }
     } }
 
@@ -196,9 +242,14 @@ fun VivamyoMonitoringView(appState: AppState) {
                 Text("NIRS Monitoring", fontSize = 13.sp, color = MlSecondaryText)
             }
             Spacer(modifier = Modifier.weight(1f))
-            Text("$batteryLvl%", fontSize = 13.sp, color = MlSecondaryText)
+            if (isDemoMode) {
+                Text("DEMO", fontSize = 11.sp, fontWeight = FontWeight.Bold, color = Color.White,
+                    modifier = Modifier.clip(RoundedCornerShape(4.dp)).background(Color(0xFFFF9500)).padding(horizontal = 6.dp, vertical = 2.dp))
+            } else {
+                Text("$batteryLvl%", fontSize = 13.sp, color = MlSecondaryText)
+            }
             Spacer(modifier = Modifier.width(8.dp))
-            Box(modifier = Modifier.size(10.dp).clip(CircleShape).background(if (isConnected) Color.Green else Color.Red))
+            Box(modifier = Modifier.size(10.dp).clip(CircleShape).background(if (isDemoMode || isConnected) Color.Green else Color.Red))
         }
 
         if (showDisconnectionBanner) {