Privacy Policy for Plumb Bob

Effective date: [2026-09-10]

The short version

Plumb Bob draws a gravity-driven plumb line. It reads the device gravity sensor while it is running, computes an angle from vertical, and displays it. There is no server, no account, and no local storage.

Information Plumb Bob stores locally

None. Plumb Bob does not save preferences, measurement history, or any other file. Every session starts from an empty state.

How the gravity sensor is used

Android exposes the gravity vector through a permission-free API. Plumb Bob subscribes to sensor events while its screen is visible, computes the tilt of the plumb line frame by frame, and unsubscribes when you leave the app. On devices without a dedicated gravity sensor, the app falls back to the accelerometer through the same permission-free API. Sensor samples are held in memory only for the current animation frame.

Information we do not collect

• We do not collect your name, email, phone number, or account.
• We do not read your camera, microphone, storage, or clipboard.
• We do not receive location data.
• We do not receive analytics, telemetry, or crash reports.
• We do not record how often you use the app or what surfaces you measure.

Android permissions

Plumb Bob declares zero Android permissions in its manifest. Ordinary motion-sensor sampling on Android does not require a runtime permission, so the app can function fully without any.

Network use

The app does not request the android.permission.INTERNET permission and does not open network sockets, so no data can be transmitted off your device.

Third parties

The APK contains no advertising library, no analytics SDK, no crash reporter, and no billing client. Nothing else runs inside the app to phone home.

Children

Plumb Bob collects nothing about anyone, so it is safe for classroom and family use, including by children under 13.

Updates to this policy

If we ever change what data the app touches on your device, we will update the effective date at the top of this page.