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v1on device

coin-flip

v1.0 has run on my own device since 9 August 2026. A smoother toss and a Play Store release come next.

Source: private repositoryAsk for a walkthrough

Problem

coin-flip is an Android app for one job: settling a call with a coin toss you can trust. The result is drawn first, and the 3D toss is choreographed to land on it. It asks for no permissions and works offline, and the result is announced to TalkBack. v1 runs on my own device, but it is not done: smoothing the toss and the camera follow, and then a Play Store release, are still ahead.

Pipeline

The result is decided first. A cryptographic 50/50 draw picks heads or tails before the toss, and the animation is choreographed to land on it.

In: a tap

  1. 01

    Fair draw

    A cryptographic 50/50 draw picks heads or tails.

  2. 02

    Choreographed toss

    The 3D toss is choreographed to land on the drawn result.

  3. 03

    Landing and settle

    The coin comes to rest on the drawn face.

  4. 04

    Haptic pulse and announcement

    A short pulse, and TalkBack announces the result.

Out: a fair result, felt and announced

Privacy

coin-flip keeps everything on the device.

  • No permissions: the release build asks for none.
  • Fully offline: no internet permission and no remote services.
  • No ads, no trackers, no accounts.

Metrics

Permissions
0
Checked on the release APK
Result split
50/50
A cryptographic draw decides each result

Demo

One toss, recorded from the screen of my own device.

A coin lies flat on a dark screen. About a second and a half in, it is flipped: it rises toward the viewer, turns over several times, then drops back and lands flat. It comes to rest face up, and the word HEADS appears below it.

Stack

Language

  • Kotlin

Platform

  • native Android

Next steps

Full route log
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