Christoph Wiesner
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AndroidProduct DesignSide ProjectUser Research

Visual Timer

A side project turned 500K-download Android app — built around intuitive circular time visualization, shaped by real user feedback over 28 iterative releases.

Context

Visual Timer started as a passion project inspired by Jake Knapp’s “Sprint” — a timer app built around circular visual time representation. The idea: displaying time as a shrinking circle segment makes duration feel tangible, even for users who struggle with abstract time concepts.

What started as a personal tool grew into a product with 500,000+ downloads and a 4.6-star rating on Google Play — almost entirely through organic growth.

What I did

I designed, built, and maintained the app end-to-end: product decisions, UX design, Android development, and growth experimentation.

Core design decisions:

  • Circular time display with direct manipulation — set duration by tapping or swiping on the circle, no separate input dialogs
  • MVP scoped to timer setup (seconds/minutes up to 60), screen-on during countdown, quick-access notifications, customizable alarms, and preset timers

Iterative development (28 updates in 16 months):

  • Added pause/resume, dark theme, app-level volume control, Android app shortcuts, tablet optimization, and landscape support
  • Integrated a feedback tool to track feature requests and pain points systematically
  • Smart preset ordering by usage frequency — the app learns what you use most
  • Crowdsourced translations in 8 languages to increase discoverability

Responding to users, not just reacting: Early reviews revealed a wrong assumption — users expected clockwise timer progression. Rather than blindly following every request, I added a direction setting while keeping the original default. The distinction between systemic problems worth fixing and individual feature requests requiring deeper validation became a core principle.

Growth experimentation:

  • A/B tested icons and promo videos — simplified icon designs outperformed conceptual ones by 17-35%
  • App Bundle adoption reduced install size by up to 64%

Outcome

  • 500,000+ installs, 4.6-star rating
  • Nearly 100% organic growth — no paid acquisition
  • 28% of sessions use custom presets, indicating strong engagement with power features

View on Google Play