Launching today
Hinge Caliper
Turn your iPhone Duo's hinge into a precision caliper
2 followers
Turn your iPhone Duo's hinge into a precision caliper
2 followers
Hinge Caliper turns the iPhone Duo's precision hinge into a measuring tool. Close your Duo on any object and it computes the thickness from the hinge angle — then vibrates and speaks the measurement aloud, so you don't need to see the screen. Includes a 0–180° protractor dial, outer-display mirroring while you work, plus on-screen rulers and bubble levels that run on any iPhone. No ads, no data collection, works offline. $0.99.
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Hi PH! I'm Daniel, an indie iOS developer. Every iPhone Duo review this week says the same thing — the hardware's ready, the apps aren't. I wanted to build something that's ready on day one.
When Apple announced the Duo — its first foldable — I got obsessed with one question: what can you do with a precision hinge that you can't do with a flat phone?
Hinge Caliper is my answer. Close the Duo on anything — a coin, a bolt, a Lego brick — and it works out the thickness from the hinge angle, then speaks the measurement aloud so you don't have to look at the screen. There's also a 0–180° protractor for the exact opening angle, and the readings can mirror onto the outer display.
The fun part: I built all of this for hardware I'd never touched, entirely against Apple's hinge APIs and the Xcode Simulator. v1.0 is live on the App Store now, ready for Duo launch day.
I've got 5 App Store promo codes for anyone who wants to try Hinge Caliper — drop a reply here and I'll pick 5 at random to send them to.
Happy to answer anything — especially from fellow devs curious about building for foldables. And if you grab it, a rating on the App Store means the world for a $0.99 indie app.