Aletra: Multisensor Logger
Measure, log and export data
Only for iPhone
$1.99
iPhone
The 3 a.m. hum, the buzz in your speakers, or a 3D magnetic map of a room: measured, timestamped and exported to CSV. No cloud, no account.
Your iPhone carries a magnetometer, a barometer, an accelerometer, a compass, a microphone that reaches down into infrasound, and a LiDAR scanner. Aletra puts them to work together: it measures, shows what it measures, timestamps every reading and exports the lot to CSV.
Aletra records. It does not interpret or draw conclusions for you. What the numbers mean is your call, and that is the whole point.
WHAT PEOPLE USE IT FOR
- The hum you only hear at night. Leave the iPhone resting somewhere, turn on background monitoring and go to sleep. In the morning you have every episode with its time, its level in the 15-22 Hz band and its vibration, ready to export.
- The interference bleeding into your speakers. Open the EMF detector and walk slowly: the reading rises as you approach the source. Wiring, a transformer, a charger behind the furniture.
- The home studio. Before you settle on a mic position, survey the room and see where the field is lowest. And measure how far your microphone actually reaches in the low end instead of assuming it.
- Vibration from upstairs or from traffic. Hits counted, with time and magnitude in g. Documenting a recurring nuisance is far more convincing with a table than with a complaint.
- School physics and citizen science. Real series, statistics (mean, standard deviation, percentiles, IQR outliers), calibration against a reference instrument and CSV for any spreadsheet.
- Places with a reputation. This is not an app that tells you "something is here": it is what you need to rule out the ordinary. Every spike can be tagged with its everyday cause (the air conditioning, traffic, a phone nearby), and whatever is left unexplained is the only thing worth a second look.
THE SURVEY: WHAT NOBODY ELSE DOES
Walk a room. LiDAR rebuilds it in 3D and knows where you are at every moment, so each magnetic field reading is pinned to the exact point where it was taken.
When you finish you have the room's 3D model with the values spread through the space: blue where the field is lowest, red where it is highest, with the microteslas at each end. It is saved with photos of the place, so a month later you know where you made it. And you can go back, ask the app to recognize the room and repeat the measurement at the same spot.
A survey detects nothing. It draws where each value was measured, which is a different and far more useful thing.
WHAT IT MEASURES
- Magnetic field in µT, with the direction of each spike noted by the compass.
- Sound: live spectrum and a watch on the 15-22 Hz band, with auto-recording and 0.25x playback.
- Pressure: the jumps a door or a vent produces in a sealed room.
- Vibration and hits with the accelerometer and gyroscope.
- Scene luminance through the camera, plus object proximity.
BUILT TO WORK
- Sessions: one button opens the log, turns the sensors on and groups everything with its time and place. When you finish you review it and export it.
- Full watch: every sensor at once, with correlation across them so you can see what moved together.
- Range alerts with haptics and sound when a reading leaves your band.
- It keeps measuring with the screen locked, and gives up the expensive sensors on its own before the phone heats up.
- Demo mode to try the app with no sensors, everything it makes tagged DEMO.
- In English and Spanish.
YOUR DATA IS YOURS
No account, no analytics, no ads. Aletra does not connect to the internet at all. Everything lives on your iPhone, and exports show up in the Files app under On My iPhone > Aletra. Nothing leaves unless you send it.
BEFORE YOU BUY
Aletra is not a certified measuring instrument. Readings depend on the iPhone's own sensors and on ambient conditions. Do not rely on it for safety or health decisions, or to assess electrical or structural hazards.
The survey's 3D mesh needs an iPhone with a LiDAR scanner; without one the survey still records the path and the readings, just no mesh. Everything else runs on any supported iPhone.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, RAUL JIMENO MARTINEZ, 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 Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- RAUL JIMENO MARTINEZ
- Size
- 3.4 MB
- Category
- Utilities
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English and Spanish
- Age Rating
4+
- 4+
- Copyright
- © 2026 Raul Jimeno
