In 2020 I acquired a MAG-ic Probe Thickness Caliper.  A great little tool and super handy.  I was disappointed by the lack of support for mobile devices given that it was Bluetooth compatible.

In early 2020, I created the Magic Caliper iOS App to interface to the MAG-ic Probe.  Many thanks to Liam at MAG-ic Probe for helping to refine the app.  For the Android version, look here.

Note:  Magic Tech, the makers of MAG-ic Probe are no longer making the Bluetooth Low Energy (BLE) version.  The new version works only with WiFi.  If you own a version of the probe purchased after April 2021, it is likely the WiFi version.  The two probes look nearly identical, but the WiFi version has a small push button switch located near the USB connector, the BLE version does not have this switch.

For support issues, questions or suggestions, contact me at magiccaliper@gmail.com.

You can see some screenshots (in light and dark mode) below:

This slideshow requires JavaScript.

For more information on MAG-ic probe thickness calipers look here.

How to start using the app:

1. Install the App on a compatible device.  Get your MAG-ic probe ready to begin calibration with one of the magnets that comes with the unit.
2. For best results, leave the MAG-ic probe unpowered until you start the app.  The reason for this is that the MAG-ic probe will only connect to the phone within 10 seconds of being powered on.   Open the app and it will automatically start looking for the MAG-ic Probe.
3. Power on the MAG-ic probe.  The app will discover the device and connect.
4. Next, you will be prompted to begin calibration.  When prompted, attach your choice of the two magnets.
5. The calibration process will continue.  Leave the magnet attached and held away from any interfering magnetic fields.  When prompted to do so, remove the magnet.
6. The final calibration step will finish with no magnet. Again ensure that the MAG-ic probe is held away from any interfering magnetic fields and at least 12’/30cm from the magnets.
7. Once calibration is complete, the screen will automatically go into measurement mode.   The app supports both portrait and landscape modes.  As well, the screen will be prevented from going into power-saving mode while measuring.  Loss of signal, or powering off the MAG-ic probe will cause the application to provide a Time-out warning.  The app will go back to searching for the MAG-ic probe and the calibration steps will need to be repeated when the device is found again.

How to create a record of measurements:

1. You can create a record of a series of measurements.  These are stored in a file on the device.  To access these you may need to install the “Files” app from Apple.  Note that it typically comes pre-installed.
2. To begin recording select the pencil and paper icon.   The application will prompt you for the filename where the measurements will be stored.
3. Once the file name is provided the measurements will begin and use the units that were selected in measurement mode.
4. The display will note the value being recorded, starting at #1 and incrementing with each value recorded.
5. To end the recording, select the pencil icon again.  A notice will appear reminding the user of the filename and location.  The file is a comma-separated-value (CSV) file format that can be used with text editors or spreadsheet software.  It will contain the timestamp for when the recording started, the units and the indexed series of measurements.   NOTE:  uninstalling the app deletes the files and the folder.

Accessing the record of measurements file:

You can access the measurements file via the devices or from a PC or Mac.

From the device, the file of recorded values can be emailed or otherwise shared via the “Files” application from Apple.  A shortcut to the “Files” application is available in the app via the folder icon.  Due to limitations in opening the “File” application, you will need to navigate to the folder location.  Select: Browse > On my iPhone/iPad > Magic Caliper.  Note that if the “Files” app is left open you may need to exit and re-enter the Magic Caliper folder for new files to appear.  From here you can use “Files” to email or otherwise share the file of recorded measurements. This folder will not appear until a recording is made.

For PC or Mac, you can retrieve the files by plugging the device into a computer via USB:

• for Mac: select the device from the Locations in “Finder” and select “Files”.  The files will be located in the Magic Caliper folder.
• for Windows: open iTunes, select you phone so that you can see the details, backups, and options.  From the left menu, under “settings” select “FileSharing” and in the list of applications select Magic Caliper

How to use the record file with MAG-ic Probe software:

The file’s measurement values can be used to create an isopach thickness map with the MAG-ic Probe software if you have purchased it.   With the software, perform a PreMap Locations on your instrument picture and SAVE WORKSPACE.  The created text file will have a sequence of locations.  Measuring each of these in sequence with Magic Caliper, then sharing the file back to your computer.  Using a spreadsheet program, use the PreMap file and insert the measured values into the 3rd column of the file.  There will now be four columns, x and y coordinates, the measured values from Magic Caliper, and a column of zeros for each of the measurement points.  This file is then loaded into the software.

Help with the app:

• The app communicates to the probe when the app is active on the screen.  You can switch applications and return but doing so during connecting and calibration is not advised.
• The app is designed to reset to the start should the MAG-ic probe signal be lost.  However, should the app get stuck waiting for a response from the probe, you can reset it by using the re-connect button (circle with an arrow).  You will likely need to remove and re-apply power to the MAG-ic probe in this case.  The MAG-ic probe firmware requires that it go through a calibration sequence every time it is powered on.

Compatibility:

This app requires iOS 11 or later, which is supported on these and newer devices:

iPhone

Privacy Policy:

Lastly to view the privacy policy of the app, look here.