Magnetic Sensor

Real-time magnetometer readouts on your phone. Use it as a tilt-compensated compass, a metal detector with haptic alerts, or a CSV-exporting field logger.

Magnetic Sensor turns your phone's built-in magnetometer into three precise tools:

• Compass — A live, tilt-compensated compass with cardinal direction (N/E/S/W) and adjustable magnetic declination so the needle points to true north, not just magnetic north.

• Metal Detector — Set a baseline reading anywhere, choose Low/Med/High sensitivity, and feel haptic pulses that get stronger as the field deviates. Perfect for finding studs in a wall, screws under drywall, or rebar in concrete.

• Field Logger — Record samples at up to 60 Hz, then export to CSV via the share sheet. Saved recordings stay in the app for replay or re-export.

KEY FEATURES • Live X / Y / Z axis readings + total field magnitude • Tilt-compensated heading using the accelerometer • Magnitude history sparkline + multi-channel chart • Rolling statistics: mean, standard deviation, RMS, range • Figure-8 calibration helper with quality indicator • Min / Max tracking with one-tap reset • Three sample rates: Slow (500 ms), Normal (100 ms), Fast (16 ms) • Light / Dark / System theme • English and Korean • Unit options: μT, mGauss, nT • Adjustable smoothing • Magnetic declination presets • Haptic alerts for the detector • Keep-screen-awake while recording • CSV export with full timestamp + per-axis data

PRIVACY All sensor data is processed on-device and never leaves your phone. The app does not collect location, contacts, or personal information. Anonymous mobile advertising is used to keep the app free; you can watch a rewarded ad to unlock unlimited CSV sharing for the session.

WHO IT'S FOR • Hobbyists exploring magnetic fields • DIYers detecting screws, studs, and rebar • Students collecting data for physics or geology projects • Hikers wanting a reliable phone compass • Anyone curious about the invisible field around them

REQUIREMENTS A device with a magnetometer (most phones built since ~2013). The app cannot work on devices without one — it will tell you on launch.