DK Timer

Context

Built for reliability during physical exercise: a minimal, single-purpose workout interval timer for EMOM and Tabata sessions, rather than a general-purpose fitness app with a timer bolted on.

What I delivered

• Kotlin + Jetpack Compose UI on Material 3, with Hilt for dependency injection and a clean-architecture split across domain, data, and ui layers.
• A drift-free timer engine: every interval boundary is anchored to startTime + N × intervalMillis and recalculated on each tick, instead of accumulating error through a naive sleep loop. Pause/resume works the same way, accumulating total paused duration and subtracting it from elapsed time (effectiveElapsed = now - startTime - totalPausedMs), so accuracy holds across any number of pauses.
• DataStore-backed presets for both timer types, sound feedback on the alarm stream (so it ignores silent mode) and vibration feedback, each independently toggleable.
• Static analysis (detekt) and unit tests running in CI.

Outcome

Shipped and actively maintained, with four tagged releases from v1.0.0 through v2.2.0.