Support

Write to [email protected] — a real person reads it, usually answering within two business days.

What to include

The app version (Settings → the version line at the bottom), your phone model, and what you expected to happen. In Settings there is Send feedback, which attaches the app version, the platform and the in-app log to the message — it tells you exactly what is being sent before it goes, and it can attach a picture of the screen you were looking at if you switch that on.

Is the measurement accurate?

Frequency is reliable up to roughly 10 kHz on a calibrated device. Depth is an estimate and is always shown with an error bar. The method, including its limits, is published in the Guide.

Why does my phone need calibrating?

The measurement uses the camera's rolling shutter, whose exact row rate differs per device. Pointing at any mains lamp calibrates it in seconds.

My phone says it is not supported

Some Android phones do not expose manual exposure control, without which the method cannot work. The app says so plainly rather than returning a number it cannot stand behind.

Refunds

Purchases are handled by the store, so a refund is requested there — and the two stores work differently, which is worth knowing before you write to anyone.

On Android: Google Play → Order history → Report a problem. If Play declines and you believe the app is at fault, write to us: a Play purchase is one we can refund ourselves, and we would rather do that than argue.

On iPhone and iPad: reportaproblem.apple.com. Apple issues every App Store refund and a developer has no way to return an App Store payment — we cannot refund you there, and it would be dishonest to promise it. Write to us anyway if the app is at fault: we will tell you exactly what to put in the request, and fix the defect.

Privacy

What the app does with data is written out in full on the privacy page.