Passive Split Timer Watch App

I’m building a native watchOS app, paired with an iOS companion, that uses the Apple Watch’s accelerometer to create passive motion-detection timer splits. Everything must be written in SwiftUI (no storyboards) and designed to work offline-first, syncing seamlessly with the iPhone as soon as a connection is available.

Core experience
• Passive motion detection drives the auto-split logic; the user never taps to mark laps—movement alone does that.
• Subtle haptic “success” taps confirm each detected split.
• At a glance, users can view current split progress through rich complications on all supported watch faces.

Companion iOS app
The iPhone app mainly handles data review, settings, and background sync. It shares a single SwiftUI codebase where practical and uses CoreData + CloudKit to keep workouts consistent whether the devices are connected or not.

End-to-end delivery
1. Fully functional watchOS app with passive split detection, haptic feedback, and complications.
2. iOS companion with history, settings, and offline-first sync.
3. App Store assets, provisioning, TestFlight build, and final submissions for both targets.

Acceptance criteria
– Splits fire accurately under typical running motion in airplane mode.
– Success haptic triggers within 0.2 s of each split event.
– Complications refresh within the system-allowed window and never exceed power-budget guidelines.
– Sync resolves conflicts automatically when connectivity resumes.
– App Store review passes without rejection.

If you’re comfortable owning architecture, SwiftUI animations, CoreMotion, CoreHaptics, Complications API, and the full submission workflow, let’s talk.