slight Rei colour theme tweaks

- angular direction (0-359) + 16ths compassrose
- documented in ui README

extra/themes/rei.json

@@ -1,13 +1,13 @@
 {
   "dark": {
-    "background": "#404040",
+    "background": "#303030",
     "foreground": "#EAEAEA",
     "highlight": "#FA1504",
     "subdued": "#fda052"
   },
   "bright": {
     "background": "#fda052",
-    "foreground": "#202020",
+    "foreground": "#303030",
     "highlight": "#df2100",
     "subdued": "#EAEAEA"
   }

pi/backend/gps_service.py

@@ -1,10 +1,18 @@
 """GPS service - connects to gpsd, buffers data, handles reconnection."""
 
+import random
 import threading
 import time
 from collections import deque
 from typing import Any
 
+# ============================================================================
+# DEBUG MODE - Set True for development without GPS hardware
+# When True: skips gpsd entirely, generates realistic mock data
+# When False: connects to real gpsd (requires GPS device)
+# ============================================================================
+_GPS_DEBUG = True
+
 # gpsdclient is a modern, simple gpsd client
 # Install gpsd on Pi: sudo apt install gpsd gpsd-clients
 # Configure: sudo nano /etc/default/gpsd (set DEVICES="/dev/ttyUSB0" or similar)
@@ -32,6 +40,10 @@ class GPSService:
         # Callback for push-based updates
         self._on_data_callback = None
 
+        # Periodic status logging
+        self._last_status_log = 0.0
+        self._fix_count = 0
+
     def set_on_data(self, callback):
         """Set callback for new GPS fix. Called with fix dict."""
         self._on_data_callback = callback
@@ -57,6 +69,7 @@ class GPSService:
         self._running = True
         self._thread = threading.Thread(target=self._reader_loop, daemon=True)
         self._thread.start()
+        print("[GPS] Service started")
 
     def stop(self):
         """Stop background reader."""
@@ -66,6 +79,7 @@ class GPSService:
 
     def _reader_loop(self):
         """Main reader loop with reconnection logic."""
+        print("[GPS] Reader thread running")
         while self._running:
             try:
                 self._connect_and_read()
@@ -76,23 +90,40 @@ class GPSService:
 
     def _connect_and_read(self):
         """Connect to gpsd and read data."""
+        # Debug mode: skip gpsd entirely, use stub data
+        if _GPS_DEBUG:
+            print("[GPS] Debug mode enabled, using stub data")
+            self._stub_mode()
+            return
+
         if GPSDClient is None:
-            # Stub mode - no gpsd client installed
             print("[GPS] gpsdclient not installed, running in stub mode")
             self._stub_mode()
             return
 
+        # Quick check if gpsd is reachable before attempting connection
+        import socket
+        try:
+            sock = socket.create_connection((self.host, self.port), timeout=2.0)
+            sock.close()
+        except (socket.timeout, socket.error, OSError) as e:
+            print(f"[GPS] gpsd not reachable at {self.host}:{self.port}: {e}")
+            raise ConnectionError(f"gpsd not reachable: {e}")
+
         try:
             client = GPSDClient(host=self.host, port=self.port)
         except Exception as e:
-            print(f"[GPS] Cannot connect to gpsd at {self.host}:{self.port}: {e}, falling back to stub mode")
-            self._stub_mode()
-            return
+            print(f"[GPS] Cannot connect to gpsd at {self.host}:{self.port}: {e}")
+            raise ConnectionError(f"gpsd connection failed: {e}")
 
         with client:
             self._connected = True
             print(f"[GPS] Connected to gpsd at {self.host}:{self.port}")
 
+            self._last_status_log = time.time()
+            self._fix_count = 0
+            first_fix_timeout = time.time() + 5.0  # 5s to get first fix
+
             for result in client.dict_stream(filter=["TPV"]):
                 if not self._running:
                     break
@@ -106,8 +137,20 @@ class GPSService:
                     "speed": result.get("speed"),  # m/s
                     "track": result.get("track"),  # heading in degrees
                     "mode": result.get("mode"),    # 0=no fix, 2=2D, 3=3D
+                    "satellites": result.get("satellites"),  # from SKY messages
                 }
 
+                # Check if this is a real fix (has position) or just empty TPV
+                if fix.get("lat") is None and fix.get("mode") in (None, 0, 1):
+                    # No real data yet, check timeout
+                    if time.time() > first_fix_timeout:
+                        print("[GPS] No GPS fix after 5s, will retry connection")
+                        raise ConnectionError("No GPS fix within timeout")
+                    continue  # Skip empty fixes
+
+                # Got real data, disable timeout
+                first_fix_timeout = float('inf')
+
                 with self._lock:
                     self._latest = fix
                     if fix.get("lat") is not None:
@@ -117,27 +160,110 @@ class GPSService:
                 if self._on_data_callback:
                     self._on_data_callback(fix)
 
+                # Periodic status log (every 5s)
+                self._fix_count += 1
+                now = time.time()
+                if now - self._last_status_log >= 5.0:
+                    elapsed = now - self._last_status_log
+                    fps = self._fix_count / elapsed
+                    speed = fix.get('speed', 0) or 0
+                    track = fix.get('track', 0) or 0
+                    mode = fix.get('mode', 0) or 0
+                    sats = fix.get('satellites', '?')
+                    print(f"[GPS] {fps:.1f} fix/s | {speed:.1f}m/s hdg={track:.0f}° mode={mode} sats={sats}")
+                    self._last_status_log = now
+                    self._fix_count = 0
+
     def _stub_mode(self):
-        """Fake data for testing without gpsd."""
-        import random
+        """Generate realistic mock GPS data for development/testing.
+
+        Simulates:
+        - Normal 3D fix with satellites
+        - Occasional signal loss (~3% chance per second, lasts ~5s)
+        - Wandering position near Tokyo
+        """
+        self._last_status_log = time.time()
+        self._fix_count = 0
+
+        # Signal loss state
+        signal_lost = False
+        signal_lost_until = 0.0
+
+        # Base position (Tokyo area)
+        base_lat = 35.6762
+        base_lon = 139.6503
+        base_alt = 40.0
+
+        # Smoothly varying heading/speed
+        heading = random.uniform(0, 360)
+        speed = random.uniform(5, 15)
 
         while self._running:
             self._connected = True
-            fix = {
-                "time": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
-                "lat": 35.6762 + random.uniform(-0.001, 0.001),
-                "lon": 139.6503 + random.uniform(-0.001, 0.001),
-                "alt": 40.0 + random.uniform(-5, 5),
-                "speed": random.uniform(0, 30),
-                "track": random.uniform(0, 360),
-                "mode": 3,
-            }
+            now = time.time()
+
+            # Check for signal loss simulation
+            if signal_lost:
+                if now >= signal_lost_until:
+                    signal_lost = False
+                    print("[GPS] Signal recovered (stub)")
+            else:
+                # ~30% chance per second to lose signal
+                if random.random() < 0.3:
+                    signal_lost = True
+                    signal_lost_until = now + 2 # fixed 2s loss
+                    print("[GPS] Signal loss simulation (stub)")
+
+            if signal_lost:
+                # No fix - mode 1, no satellites, no track
+                # Note: use None, not float('nan') - NaN doesn't serialize to valid JSON
+                fix = {
+                    "time": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
+                    "lat": None,
+                    "lon": None,
+                    "alt": None,
+                    "speed": None,
+                    "track": None,
+                    "mode": 1,
+                    "satellites": 0,
+                }
+            else:
+                # Smoothly vary heading and speed
+                heading = (heading + random.uniform(1, 3)) % 360
+                speed = max(0, min(30, speed + random.uniform(-2, 2)))
+
+                fix = {
+                    "time": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
+                    "lat": base_lat + random.uniform(-0.001, 0.001),
+                    "lon": base_lon + random.uniform(-0.001, 0.001),
+                    "alt": base_alt + random.uniform(-5, 5),
+                    "speed": speed,
+                    "track": heading,
+                    "mode": 3,
+                    "satellites": random.randint(6, 12),
+                }
+
             with self._lock:
                 self._latest = fix
-                self._buffer.append(fix)
+                if fix.get("lat") is not None:
+                    self._buffer.append(fix)
 
             # Invoke callback with new fix
             if self._on_data_callback:
                 self._on_data_callback(fix)
 
+            # Periodic status log (every 5s)
+            self._fix_count += 1
+            if now - self._last_status_log >= 5.0:
+                elapsed = now - self._last_status_log
+                fps = self._fix_count / elapsed
+                speed_val = fix.get('speed') or 0
+                track_val = fix.get('track')
+                track_str = f"{track_val:.0f}" if track_val is not None else "---"
+                mode = fix.get('mode', 0)
+                sats = fix.get('satellites', 0)
+                print(f"[GPS] {fps:.1f} fix/s | {speed_val:.1f}m/s hdg={track_str} mode={mode} sats={sats} (stub)")
+                self._last_status_log = now
+                self._fix_count = 0
+
             time.sleep(1)

pi/ui/lib/README.md

@@ -34,6 +34,7 @@ All services use singleton pattern with `ServiceName.instance`.
 |--------|---------|
 | `NavigatorWidget` | Animated character with emotion states (images precached at startup) |
 | `AccelGraph` | Real-time accelerometer visualization with gravity compensation |
+| `GpsCompass` | GPS heading compass with rotating navigation icon and degree readout |
 | `WhiskeyMark` | Gimbal-style horizon indicator using IMU roll/pitch |
 | `SystemBar` | Top status bar (time, connection, Pi temp) |
 | `StatBox` | Reusable metric display box |

pi/ui/lib/app_root.dart

@@ -19,7 +19,7 @@ class AppRoot extends StatefulWidget {
 class _AppRootState extends State<AppRoot> {
   bool _initialized = false;
   bool _overheatTriggered = false;
-  String _initStatus = 'Starting...';
+  final Map<String, String> _initStatuses = {};
 
   @override
   void initState() {
@@ -33,27 +33,32 @@ class _AppRootState extends State<AppRoot> {
     super.dispose();
   }
 
+  void _updateStatus(String key, String value) {
+    setState(() => _initStatuses[key] = value);
+  }
+
   Future<void> _runInitSequence() async {
-    // Load config first
-    setState(() => _initStatus = 'Loading config...');
+    // Show all items from the start so the row doesn't jump around
+    _updateStatus('Config', '...');
+    _updateStatus('UART', '...');
+    _updateStatus('Navigator', '...');
+
+    // Config must load first (everything else depends on it)
+    _updateStatus('Config', 'Loading');
     await ConfigService.instance.load();
+    _updateStatus('Config', 'Ready');
 
-    setState(() => _initStatus = 'Checking systems...');
+    // UART health check and navigator image preload run truly in parallel
+    _updateStatus('UART', 'Connecting');
+    _updateStatus('Navigator', 'Loading');
+    await Future.wait([
+      _waitForUart(),
+      _preloadNavigatorImages(),
+    ]);
+
+    // Let the user see the all-ready state for a moment
     await Future.delayed(const Duration(milliseconds: 500));
 
-    // Check UART connection via backend health endpoint
-    // Also preload navigator images in parallel (usually UART is the bottleneck)
-    setState(() => _initStatus = 'UART: connecting...');
-    final imagePreloadFuture = _preloadNavigatorImages();
-    await _waitForUart();
-    await imagePreloadFuture;
-
-    setState(() => _initStatus = 'GPS: standby');
-    await Future.delayed(const Duration(milliseconds: 400));
-
-    setState(() => _initStatus = 'Ready');
-    await Future.delayed(const Duration(milliseconds: 300));
-
     // Start overheat monitoring
     OverheatMonitor.instance.start(
       onOverheat: () {
@@ -78,11 +83,8 @@ class _AppRootState extends State<AppRoot> {
 
         if (response.statusCode == 200) {
           final data = jsonDecode(response.body) as Map<String, dynamic>;
-          final arduinoOk = data['arduino_connected'] == true;
-
-          if (arduinoOk) {
-            setState(() => _initStatus = 'UART: OK');
-            await Future.delayed(const Duration(milliseconds: 300));
+          if (data['arduino_connected'] == true) {
+            _updateStatus('UART', 'Ready');
             return;
           }
         }
@@ -90,28 +92,24 @@ class _AppRootState extends State<AppRoot> {
         // Backend not reachable yet - keep trying
       }
 
-      // Not connected yet
-      setState(() => _initStatus = 'UART: waiting...');
+      _updateStatus('UART', 'Waiting');
       await Future.delayed(retryDelay);
     }
 
     // Timeout - proceed anyway (UI will show stale data indicators)
-    setState(() => _initStatus = 'UART: timeout');
-    await Future.delayed(const Duration(milliseconds: 500));
+    _updateStatus('UART', 'Timeout');
   }
 
   /// Preload navigator images into Flutter's image cache
   ///
   /// Scans for all PNGs in the navigator folder and precaches them.
-  /// Runs silently - no status updates (meant to run parallel with UART).
   Future<void> _preloadNavigatorImages() async {
     final images = await ConfigService.instance.getNavigatorImages();
     for (final file in images) {
-      // precacheImage needs a context, but we're in initState territory
-      // Use the root context via a post-frame callback workaround
       if (!mounted) return;
       await precacheImage(FileImage(file), context);
     }
+    _updateStatus('Navigator', 'Ready');
   }
 
   @override
@@ -121,7 +119,7 @@ class _AppRootState extends State<AppRoot> {
     if (_overheatTriggered) {
       child = const OverheatScreen(key: ValueKey('overheat'));
     } else if (!_initialized) {
-      child = SplashScreen(key: const ValueKey('splash'), status: _initStatus);
+      child = SplashScreen(key: const ValueKey('splash'), statuses: _initStatuses);
     } else {
       child = const DashboardScreen(key: ValueKey('dashboard'));
     }

pi/ui/lib/screens/dashboard_screen.dart

@@ -13,6 +13,7 @@ import '../widgets/system_bar.dart';
 import '../widgets/debug_console.dart';
 import '../widgets/whiskey_mark.dart';
 import '../widgets/accel_graph.dart';
+import '../widgets/gps_compass.dart';
 
 // test service for triggers
 import '../services/test_flipflop_service.dart';
@@ -55,6 +56,7 @@ class _DashboardScreenState extends State<DashboardScreen> {
 
   // From backend - GPS data
   double? _gpsSpeed;
+  double? _gpsTrack;
 
   // Placeholder values for system bar
   int? _gpsSatellites;
@@ -105,8 +107,8 @@ class _DashboardScreenState extends State<DashboardScreen> {
     _gpsSub = WebSocketService.instance.gpsStream.listen((data) {
       setState(() {
         _gpsSpeed = data.speed;
-        // Derive satellites from mode (placeholder logic)
-        _gpsSatellites = data.mode == 3 ? 8 : (data.mode == 2 ? 4 : 0);
+        _gpsTrack = data.track;
+        _gpsSatellites = data.satellites;
       });
     });
 
@@ -140,7 +142,8 @@ class _DashboardScreenState extends State<DashboardScreen> {
     final cachedGps = WebSocketService.instance.latestGps;
     if (cachedGps != null) {
       _gpsSpeed = cachedGps.speed;
-      _gpsSatellites = cachedGps.mode == 3 ? 8 : (cachedGps.mode == 2 ? 4 : 0);
+      _gpsTrack = cachedGps.track;
+      _gpsSatellites = cachedGps.satellites;
     }
 
     _wsState = WebSocketService.instance.connectionState;
@@ -203,11 +206,11 @@ class _DashboardScreenState extends State<DashboardScreen> {
                     wsState: _wsState,
                   ),
 
-                  const SizedBox(height: 5),
+                  const SizedBox(height: 2),
 
                   // Main content area - big stat boxes
                   Expanded(
-                    flex: 8,
+                    flex: 7,
                     child: Row(
                       children: [
                         // Attitude indicator (whiskey mark)
@@ -231,11 +234,12 @@ class _DashboardScreenState extends State<DashboardScreen> {
 
                   // Bottom stats row
                   Expanded(
-                    flex: 2,
+                    flex: 3,
                     child: Row(
                       mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                       children: [
                         StatBox(value: _formatInt(_rpm), label: 'RPM', isWarning: () => (_rpm ?? 0) > 4000),
+                        GpsCompass(heading: _gpsTrack),
                         StatBox(value: _formatGear(_gear), label: 'GEAR'),
                       ],
                     ),

pi/ui/lib/screens/splash_screen.dart

@@ -3,10 +3,12 @@ import 'package:flutter/material.dart';
 import '../theme/app_theme.dart';
 
 /// Splash screen - shown during initialization
+///
+/// Displays parallel status items that independently flip to "Ready".
 class SplashScreen extends StatelessWidget {
-  final String status;
+  final Map<String, String> statuses;
 
-  const SplashScreen({super.key, required this.status});
+  const SplashScreen({super.key, required this.statuses});
 
   @override
   Widget build(BuildContext context) {
@@ -33,13 +35,19 @@ class SplashScreen extends StatelessWidget {
                 fontWeight: FontWeight.bold,
               ),
             ),
-            const SizedBox(height: 16),
-            Text(
-              status,
-              style: Theme.of(context).textTheme.bodyLarge?.copyWith(
-                fontSize: 80,
-                color: theme.subdued,
-              ),
+            const SizedBox(height: 32),
+            Row(
+              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+              children: statuses.entries.map((entry) {
+                final isReady = entry.value == 'Ready';
+                return Text(
+                  '${entry.key}: ${entry.value}',
+                  style: Theme.of(context).textTheme.bodyLarge?.copyWith(
+                    fontSize: 48,
+                    color: isReady ? theme.foreground : theme.subdued,
+                  ),
+                );
+              }).toList(),
             ),
           ],
         ),

pi/ui/lib/services/backend_service.dart

@@ -39,8 +39,9 @@ class GpsData {
   final double? alt;
   final double? track;
   final int? mode; // 0=no fix, 2=2D, 3=3D
+  final int? satellites;
 
-  GpsData({this.lat, this.lon, this.speed, this.alt, this.track, this.mode});
+  GpsData({this.lat, this.lon, this.speed, this.alt, this.track, this.mode, this.satellites});
 
   factory GpsData.fromJson(Map<String, dynamic> json) {
     return GpsData(
@@ -50,6 +51,7 @@ class GpsData {
       alt: (json['alt'] as num?)?.toDouble(),
       track: (json['track'] as num?)?.toDouble(),
       mode: (json['mode'] as num?)?.toInt(),
+      satellites: (json['satellites'] as num?)?.toInt(),
     );
   }
 }

pi/ui/lib/services/websocket_service.dart

@@ -204,7 +204,7 @@ class WebSocketService {
         final gps = GpsData.fromJson(data);
         _latestGps = gps;
         _gpsController.add(gps);
-        _log('gps: ${gps.speed?.toStringAsFixed(1) ?? "-"}m/s mode${gps.mode ?? "-"}');
+        _log('gps: ${gps.speed?.toStringAsFixed(1) ?? "-"}m/s hdg=${gps.track?.round() ?? "-"}° mode${gps.mode ?? "-"}');
       }
     });
 

pi/ui/lib/widgets/gps_compass.dart

@@ -0,0 +1,71 @@
+import 'dart:math' as math;
+import 'package:flutter/material.dart';
+import '../theme/app_theme.dart';
+
+class GpsCompass extends StatelessWidget {
+  final double? heading;
+
+  const GpsCompass({super.key, this.heading});
+
+  bool get _hasSignal => heading != null;
+
+  String get _displayHeading {
+    if (!_hasSignal) return 'N/A'; // Just make it clear; redundant anyways, this only gets called when _hasSignal
+    return '${(heading! % 360).round()}'; // No need for the degree symbol
+  }
+
+  String get _compassDirection {
+    if (!_hasSignal) return '';
+    final directions = [
+      'N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE',
+      'S', 'SSW', 'SW', 'WSW', 'W', 'WNW', 'NW', 'NNW'
+    ];
+    final index = ((heading! % 360) / 22.5).round() % 16;
+    return directions[index];
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
+
+    // No signal = subdued color, valid = foreground
+    final iconColour = _hasSignal ? theme.foreground : theme.highlight;
+
+    // Convert to radians, 0 = no rotation when no signal
+    final angle = _hasSignal ? (heading! * math.pi / 180.0) : 0.0;
+
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: [
+        Flexible(
+          flex: 3,
+          child: Transform.rotate(
+            angle: _hasSignal ? angle : 0,
+            child: FittedBox(
+              fit: BoxFit.contain,
+              child: Icon(
+                _hasSignal ? Icons.navigation : Icons.navigation_outlined,
+                size: 120,
+                color: iconColour,
+              ),
+            ),
+          ),
+        ),
+        Flexible(
+          flex: 1,
+          child: FittedBox(
+            fit: BoxFit.contain,
+            child: Text(
+              _hasSignal ? "${_displayHeading} ${_compassDirection}" : "N/A",
+              style: TextStyle(
+                fontSize: 80,
+                color: theme.subdued,
+                fontFamily: 'DIN1451',
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}