This is a magnetic loop controller board designed by Loftur TF3LJ and VE2LJX. This PCB was designed by 9A3GOS (me) and assembled by two assembly factories. Each factory made 5 boards (minimum order quantity).
There is one via under the stepper driver which could be a little bigger, but I was driving 2 amps to a stepper motor without an issue.
Original design and documentation: https://sites.google.com/site/lofturj/to-automatically-tune-a-magnetic-loop-antenna
PDF Automatic_Magnetic_Loop_Controller_BOM_and_building_instructions_Rev3-Rev4PCB_r02Download PDF file
You can upload a compiled hex file to a teensy microcontroller or use Arduino environment to modify it and compile it yourself.
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