"Magnetscape" is a new measurement app that observe invisible magnetic fields by using a built-in iPhone magnetic sensor.
There are various magnetic fields in our surroundings. For example, the magnetic field fluctuates even with a large motor, a compressor, or a metal nearby. Earth's magnetic field exists even in places where there is nothing, and we are affected by that magnetic filed.
"Magnetscape" can monitor the surrounding magnetic field in real time, it can be used for various purposes in real life. For example, it can be used for investigation of static magnetic field, search for low electromagnetic field at alternating magnetic field (electromagnetic field), metal detection and more.
"Magnetscape" has three kinds of measurement modes for magnetic field observation, please use it according to your purpose.
Perform a graphic display that shows the magnitude and direction of the magnetic field.
In Scope, the magnetic flux density of the magnetic field is expressed by the size and color of the graphic circle.
The display position of the graphic circle, but will move to match the polarity of the magnetic source, the polarity is attracted towards the N-pole if it is the same direction as the geomagnetic field, polarity is reversed away if it is the opposite (S-pole). If there is no metal or magnetic field nearby, it will be shifted in the direction of the geomagnetism (N-pole).
- Time graph
Trace the RAW data from the magnetic sensor and its corrected data. It is a time displacement graph of each axis value (Bx / By / Bz) and composite magnetic flux density (Bcomp) in three-dimensional space. You can scroll up to 180 seconds.
- FFT analysis
Perform frequency analysis on changing magnetic field. It displays the result of FFT analysis of composite magnetic flux density.
Horizontal axis: Frequency 1 - 16 Hz (0.5 Hz)
Vertical axis: dB (ratio to default standard value 45 μT) , Reference value can be set in units of 45 ± 15 μT / 1 μT.
- Graphical display of magnetic field observation by magnetic sensor (Scope)
- Time displacement graph display of magnetic field observation (Time)
- FFT analysis (FFT)
- Magnetic field observation
X axis: intensity (Bx) of the magnetic field of (the right direction toward the screen)
Y axis: intensity (By) of the magnetic field of (upward toward the screen)
Z axis: magnetic field strength (Bz) in the of (vertical upward direction of the screen)
Composite magnetic flux density: The magnetic field strength (Bcomp) that takes all three components of the x axis, the y axis, and the z axis into consideration
Sampling frequency: 32 Hz
Unit of observation value: uT
- Measurement time: 3 minutes
- Alert function: A warning message will be displayed if the composite magnetic flux density exceeds 300 μT.
- Peak hold function on FFT mode.
- Angle display function on Scope mode (Angle)
- The display value of this application is the RAW output data from the magnetic sensor itself. It does not make any processing such as filtering processing inside the application.
- Since the magnetic sensor is a delicate device, the internal reference value of the magnetic sensor may be disturbed by being exposed to extremely strong magnets and magnetic fields for a long time.
- If the reference value of the magnetic sensor goes wrong, once you stop the application and leave it for a while, the magnetic sensor is readjusted automatically. If the magnetic sensor is still unstable, please try the electronic compass calibration and its reset procedure.
- Some improvements.
- Added the angular display.
- Requires iOS11.2 or later.
A good first attempt
The sampling frequency does not capitalize on the latest phone hardware and should be selectable, higher than just 32 hz
The peak frequency should be numerically displayed, not just a bar graph. Since the value is easily calculated, it should be displayed.
I wasted my money because I have an app with a configurable trace where I can literally count waves and compute frequency. Was hoping the FFT function would work better and actually record a value for the computed frequency.