Pandarine
The sensors work. They need their own build
The promise is a companion that grows from how you actually use your phone, not from how often you tap it. That part is built. The pedometer feeds experience all day; tilt the phone and it leans with you; lay it flat and it lies down; shake it hard and you set off an earthquake. Plug in the charger and its comfort climbs for as long as the cable stays in. Switch from Wi-Fi to mobile data and it works out that you have left the house.
None of that needs an account, a login, or your location.
The limit nobody advertises
Expo Go — the sandbox app that gets a project running on a real phone in seconds — only lets those sensors run in the foreground. Close the app and the readings stop. The companion carries on living, because decay is computed from timestamps, but it stops learning anything about you. The headline feature works exactly as long as you are looking at it.
The way out is a custom development build, and its configuration landed this week: expo-dev-client, an eas.json, and the iOS motion-usage key the platform demands before it hands over step data.
Why this is plumbing and not surgery
Everything that affects the companion is a stimulus: a set of effects and some experience. A button press and a step count are the same kind of thing to the engine.
That decision was made on day one, before there was anything to apply it to. It is why moving from tapped care to sensor input changes where the numbers come from and nothing else: the engine never learns what a pedometer is.