Train Zone — Heart-Rate Zone Training
Live BPM, adjustable target zones, and haptic alerts for focused workouts on Wear OS. Stay in zone 2 (or any zone of your choice) without glancing at anything. Perfect for endurance athletes.
Project Overview & Innovation Report
Executive Summary
TrainZone is a focused Wear OS application that helps athletes stay in their target heart-rate zone during workouts. It continuously monitors heart rate on-device and provides clear, persistent haptic feedback when you drift outside your configured zone. With an ambient-aware UI, resilient foreground service, and privacy-by-design approach, TrainZone delivers reliable, low-friction guidance right on the wrist.
Key Innovations
- 🚀Zone-aware haptic coaching with persistent vibration patterns for real-time feedback
- 🚀Resilient foreground monitoring with sticky service and wake lock management
- 🚀Ambient-aware UI with burn-in-safe, high-contrast display optimizations
- 🚀User-configurable zones with quick BPM adjustments and instant persistence
- 🚀Privacy by design with on-device processing and no network access
🚀 Core Learning Modes & Features
Main Screen - Real-time Zone Guidance
Large HR readout with color-coded feedback, status indicators, and target range display for immediate training guidance.
Highlights:
- ✓Color-coded heart rate: green in zone, red out of zone, gray awaiting
- ✓Clear status indicators showing IN ZONE / OUT OF ZONE states
- ✓Current BPM bounds display (e.g., 110-130 BPM)
- ✓Smart screen management for timely feedback when out of zone
Settings Screen - Target Zone Configuration
Simple, intuitive controls for configuring heart rate zones with safety limits and instant persistence.
Highlights:
- ✓Increment/decrement controls for min/max BPM
- ✓Safe limits enforcement with min<max validation
- ✓One-tap save to persist preferences locally
- ✓Quick access from main screen when not monitoring
Background Monitoring - Foreground Service
Resilient background heart rate monitoring with haptic feedback and system integration for reliable long-session support.
Highlights:
- ✓Sticky foreground service with ongoing notification
- ✓Real-time HR streaming to UI via binder callbacks
- ✓Periodic vibration patterns while out of zone
- ✓Partial wake lock for reliable haptic feedback
Privacy & Security by Design
Complete on-device processing with no network access, minimal permissions, and privacy-first architecture.
Highlights:
- ✓No analytics, network calls, or external storage
- ✓Minimal permissions: only sensors, vibrate, wake lock
- ✓Local preferences storage for BPM settings only
- ✓No accounts, sessions, or cloud dependencies
🤖 Performance & Architecture Excellence
TrainZone employs sophisticated Wear OS optimizations, ambient mode handling, and energy-efficient design patterns for reliable, long-session training support.
How It Works
- 🔹Ambient mode with high-contrast monochrome and reduced interactions
- 🔹Energy-efficient sensor sampling with targeted wake lock usage
- 🔹Code minification and resource shrinking for optimal performance
- 🔹Low-friction UI with large controls and glanceable feedback
🛠 Technology Stack
Wear OS
Android 13+ with Jetpack Compose for Wear
Kotlin
Version 1.9.23 with JVM target 11
Sensors API
TYPE_HEART_RATE with foreground service
Haptics
Custom vibration patterns and wake lock
💡 Why It Matters
TrainZone focuses on doing one thing exceptionally well: keeping you in your target heart-rate zone. With resilient background monitoring, ambient-aware UI, and privacy-first design, it delivers dependable training support on Wear OS for serious athletes and fitness enthusiasts.