3DFM

Automated 3D magnetic flux density mapping system

#Software and hardware

• Ubuntu 20.04
• Python 3.9
• Arduino UNO: https://store.arduino.cc/usa/arduino-uno-rev3
• Arduino gShield: https://synthetos.com/project/grblshield
• Any 3D CNC/3D printer arm (see picture in 3DFM/Photo/)
• USB Hall-probe (Metrolab THM1176 used here).

#Installation

1. Install single trigger code for the THM1176 probe (https://github.com/Hyperfine/pyTHM1176/tree/cedh/single_trig/)

   • place all 'pyTHM1176' subdirectory files into the 3DFM folder.

2. Flash GRBL 1.1h (i.e. the *.hex file) to the Arduino UNO.

   • see https://github.com/gnea/grbl/releases/
   • use HexUploader (https://github.com/paulkaplan/HexUploader) or similar

3. Change '/dev/ttyACM0/' of the 1DFM.py and 3DFM.py code to match your Arduino UNO port.

   • most often it is the same

4. Power ON the Arduino + gShield using a 24 V power supply unit

   • connect probe USB
   • connect CNC USB

5. Run 1DFM.py (projection) or 3DFM.py (volume).

#Notes

• recommend running 1DFM.py at first to test function.
• this is a very simple code to understand & reconfigure.
• must calibrate the steps for your machine (for example, x_forwords = 'G91 X-0.17 F100000')
• other detailed calibrations can be done by modifying the .hex file through Arduino IDE.
• 3DFM will map in a zig-zag pattern over a defined volume.
• current default mapping range is 13.5 cm x 13.5 cm x 1 cm in steps of 3 mm x 3 mm x 1 mm.
• this code can be modified for measurement using any other USB probe (for example, RF fields, temperature, etc)

#Various useful code

• 'rewind.py' to be used to bring gantry head back to starting point (no measurements).

#Future work

• GUI
• various functions (homing, etc)
• circular 3D filling, other motion
• Bx, By, Bz, temperature data storage
• 3D visuals of mapping region and field plotting during process