Free FTP testing extension for Hammerhead Karoo cycling computers. No subscriptions, no accounts, works completely offline.

9 data fields available for your ride screen:

Results include advanced metrics:

• Normalized Power (NP): Accounts for variability in effort
• Variability Index (VI): NP / Avg Power (1.0 = steady, >1.05 = variable)
• Efficiency Factor (EF): NP / Avg HR (tracks aerobic fitness)

WattRamp calculates 7 power zones based on your FTP:

• Progress Tracking: View all past test results with detailed analytics
• Chart Modes: Toggle between Bar, Trend (smooth Bézier curves), and Protocol comparison views
• Statistics: Best FTP, average, total gain, test count

Dedicated checklist screen before each test:

• Calibrate power meter
• Sensors connected
• Hydration ready
• FTP setting verified

8-page tutorial accessible from Home Screen → Tutorial link:

Interactive walkthrough accessible from Settings → Guide:

• Step-by-step tour of all screens (Home, Settings, History, Zones, Running, Results)
• Explains test protocols, settings, and results
• Perfect for first-time users
• Tap anywhere to advance through the guide

If the app crashes during a test, WattRamp detects the abandoned session on restart and offers to dismiss or discard it.

• Interval Changes: Visual + audio notification when phases change
• Countdown Warnings: 30-second and 10-second warnings before transitions
• Motivational Messages: "HALFWAY!", "PUSH HARDER!" encouragement
• Low Cadence Warning: Alert when cadence drops below optimal range
• Test Completion: Final FTP result with comparison to previous

Audible beep patterns using Karoo's internal beeper:

• Single beep: Interval changes
• Double beep: Test start / completion
• Triple beep: Final 30 seconds

1. Download wattramp-x.x.x.apk from Releases

2. Transfer to Karoo using one of these methods:

   Option A: USB Cable (Simplest)

   • Connect Karoo to computer via USB cable
   • Enable file transfer mode on Karoo
   • Copy APK to any folder on Karoo
   • On Karoo: open Files app → navigate to APK → tap to install

   Option B: ADB Wireless (No Cable)

   • Enable Developer Options on Karoo (Settings → About → tap Build Number 7 times)
   • Enable ADB Debugging and note IP address
   • From computer: adb connect <karoo-ip>:5555
   • Install: adb install wattramp-x.x.x.apk

   Option C: Web Server

   • Upload APK to any web server or cloud storage
   • On Karoo: open web browser, download APK, tap to install

3. Launch WattRamp from app drawer

Requirements:

• Android Studio Arctic Fox+ or JDK 17+
• Gradle 8.x

Setup GitHub Packages access (Karoo SDK requires authentication):

1. Create GitHub Personal Access Token with read:packages scope
2. Add to ~/.gradle/gradle.properties:

gpr.user=YOUR_GITHUB_USERNAME
gpr.key=YOUR_GITHUB_TOKEN

Build:

git clone https://github.com/yrkan/wattramp.git
cd wattramp
./gradlew assembleRelease

APK: app/build/outputs/apk/release/wattramp-x.x.x.apk

1. Open WattRamp on your Karoo
2. Set your current FTP (used for warmup/recovery zone calculations)
3. Configure test parameters (optional):
   • Ramp start power (default: 100W)
   • Ramp step increment (default: 20W/min)
   • Warmup/cooldown duration
   • Sound and screen wake preferences

1. Go to Profiles → Select your ride profile → Edit
2. Add a new page or edit existing
3. Tap empty slot → More Data → WattRamp
4. Select desired fields (recommended: Current Interval 2x1 + 2-3 numeric fields)

1. Start a ride (WattRamp requires an active recording)
2. Open WattRamp app during ride
3. Select test protocol (Ramp / 20-min / 8-min)
4. Follow the intervals:
   • Watch target power on data fields
   • Stay in zone (green = good, red = too low/high)
   • Listen for audio cues
5. Complete the test:
   • Ramp: Continue until you can't maintain power (auto-detects failure)
   • 20-min / 8-min: Follow all intervals to completion
6. View results and optionally save to history

[5 min Warmup @ 50%] → [Ramp: +20W every minute until failure] → [5 min Cooldown]

• Starts at configurable power (default 100W)
• Increases by configurable step (default 20W) every minute
• Auto-ends when power drops >30% below target for 10+ seconds
• FTP = Max 1-minute average × 0.75

[20 min Warmup] → [5 min Blow-out @ 105%] → [5 min Recovery] → [20 min MAX EFFORT] → [10 min Cooldown]

• Classic protocol for accurate FTP measurement
• Requires pacing strategy for 20-min effort
• FTP = 20-minute average × 0.95

[15 min Warmup] → [8 min MAX #1] → [10 min Recovery] → [8 min MAX #2] → [10 min Cooldown]

• Two efforts allow for pacing adjustment
• Average of both efforts used
• FTP = Average of two 8-min efforts × 0.90

io.github.wattramp/
├── WattRampExtension.kt     # KarooExtension service entry point
├── MainActivity.kt          # Settings UI (Jetpack Compose)
├── MainViewModel.kt         # State management for UI
├── datatypes/               # 9 Karoo data field implementations
│   ├── CurrentIntervalDataType.kt  # 2x1 graphical widget
│   ├── TargetPowerDataType.kt
│   ├── TestProgressDataType.kt
│   └── ...
├── protocols/               # FTP test protocol implementations
│   ├── TestProtocol.kt      # Base interface + common logic
│   ├── RampTest.kt
│   ├── TwentyMinTest.kt
│   └── EightMinTest.kt
├── engine/
│   ├── TestEngine.kt        # State machine, Karoo stream handling
│   ├── TestState.kt         # Sealed class for test states
│   ├── AlertManager.kt      # In-ride alert management
│   └── AnalyticsCalculator.kt  # NP, VI, EF calculations
├── data/
│   ├── PreferencesRepository.kt  # DataStore persistence
│   ├── TestHistory.kt       # Test result storage
│   └── TestSession.kt       # Session recovery data
└── ui/
    ├── screens/             # Compose UI screens
    │   ├── HomeScreen.kt         # Protocol selection, FTP display
    │   ├── ChecklistScreen.kt    # Pre-test checklist
    │   ├── SensorWarningScreen.kt # Power meter warning
    │   ├── RunningScreen.kt      # Active test display
    │   ├── ResultScreen.kt       # Test results
    │   └── ...
    └── components/          # Reusable UI (charts, guide tour)

• Thread Safety: All shared state uses AtomicInteger, AtomicLong, AtomicReference, and Mutex
• Memory Management: Bounded data structures prevent unbounded growth (max 4000 power samples)
• Karoo SDK: Uses KarooSystemService for power/HR/cadence streams, alerts, and beeps
• State Flow: Reactive state management with Kotlin StateFlow

• Ensure a ride is actively recording
• Start a test from the WattRamp app
• Check that power meter is connected

• Verify "Sound Alerts" is enabled in settings
• Check Karoo system volume
• Some older Karoo firmware may have beeper limitations

• Power must drop >30% below target for 10+ consecutive seconds
• Ensure power meter is transmitting consistently
• You can manually stop via the app if needed

• Try different calculation methods in settings (Conservative/Aggressive)
• Ensure you gave maximum effort during test intervals
• Compare with other FTP tests for validation

• Tests are only saved when you tap SAVE on the result screen
• Maximum 100 tests stored (oldest removed when exceeded)
• Clear History in Settings will remove all tests

• Session recovery will detect abandoned tests on next launch
• Check for low battery or overheating
• Try reinstalling from latest release

WattRamp is fully translated into 10 languages:

Language is automatically detected from your Karoo system settings, or can be changed manually in WattRamp Settings → Language.

• Device: Hammerhead Karoo 2 or Karoo 3
• Sensors: Power meter (required)
• Optional: Heart rate monitor (for HR zone display and EF calculation)

WattRamp respects your privacy:

• 100% Offline: No internet connection required or used
• Local Storage Only: All data stays on your device
• No Accounts: No registration, login, or cloud sync
• No Analytics: Zero tracking or telemetry
• Open Source: Verify everything yourself

• Localization Sync: All 10 languages now have identical string keys (231 strings each)
• String Cleanup: Fixed missing translations for analytics metrics (NP, VI, EF, HR) in all locales
• About Section: Added version, GitHub, Privacy, Contact links to Settings
• Protocol Cards: Consistent localized short names across all languages

• HomeScreen Redesign: Compact Garmin Edge-style layout
  • Hero FTP display (large centered value)
  • Horizontal protocol selector (RAMP / 20-MIN / 2×8-MIN)
  • Clean visual hierarchy
• Navigation Improvements: Fixed screen flickering during transitions
  • Unified navigation using popBackStack
  • Separated LaunchedEffects for different state changes
  • Proper state cleanup on test stop
• Pre-Test Checklist: Dedicated full-screen checklist before test
• Sensor Warning Screen: Clear warning when power meter not detected
• App Guide Tour: Interactive walkthrough of all screens (Settings → Guide)
• Translation Updates: Complete synchronization of all 10 languages
• UI Polish: Better spacing, typography, and touch targets

• Extended Analytics: NP, Variability Index, Efficiency Factor in results
• FTP History Charts: Bar, Trend (Bezier curves), Protocol comparison modes
• Pre-Test Checklist: Expandable reminder on home screen
• Session Recovery: Detects abandoned tests after crash/restart
• Shows up to 12 results in history (was 8)

• Fixed KarooSystem connection check before starting test
• Added settings validation with min/max bounds
• Changed default ramp start to 150W (was 100W)
• Thread-safe update job handling
• Fixed UserProfile FTP logic

• Thread safety improvements for Karoo 3 stability
• Implemented sound alerts (PlayBeepPattern)
• Fixed HR zones using actual user max HR from profile
• Fixed progress calculation for 20-min and 8-min tests
• Memory optimization with bounded data structures
• R8 minification (APK size: 17MB → 2.1MB)

• Added configurable warmup/cooldown duration
• Karoo settings integration

• Registered all 9 data types
• Localization fixes

• Performance improvements
• Added MainViewModel for state management

Contributions welcome! Please:

1. Fork the repository
2. Create feature branch (git checkout -b feature/amazing-feature)
3. Commit changes (git commit -m 'Add amazing feature')
4. Push to branch (git push origin feature/amazing-feature)
5. Open Pull Request

• Issues: GitHub Issues
• Discussions: GitHub Discussions

MIT License — see LICENSE file.

• Built with Karoo Extension SDK
• FTP protocols based on established cycling science (Coggan, Allen, Friel)

Disclaimer: WattRamp is an independent project, not affiliated with Hammerhead or SRAM. Karoo is a trademark of Hammerhead.