Magnetic Sensor
Compass • Detector • Logger
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
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.
Ratings & Reviews
- This app has not received enough ratings or reviews to display an overview.
The developer, Seonggon Sim, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Provider
- Seonggon Sim
- Size
- 26.1 MB
- Category
- Utilities
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English and Korean
- Age Rating
4+
- 4+
- Contains
Advertising
- Copyright
- © Copyright 2026. Gonigon all rights reserved.