Basic Magnetic Loop Tuner

This project was built to get my mag loop on the air and is just an Arduino UNO controlling a stepper motor.  I should mention that this is set up for a Trombone Capacitor and requires a LOT of revolutions to get it to cover from 40M to 30M to 20M.   So the code will have to be modified to change the stepping regime.   There is also only one end stop function which may need to be removed if you are using a continuous variable capacitor.

This is the schematic and the Arduino sketch. (The sketch has been saved as a .docx file as I can’t upload .ino file.  It will have to be copied and pasted to the Arduino IDE to use)

As I have dis-assembled the project to build a better one these are all the pics I have of it.

The A4988 controller mounted on a proto shield.

The A4988 controller mounted on a proto shield.

Relay that isolates the end-of-travel switch on the mag loop.

Counter to count revolutions to roughly indicate positioning, Large Knob is the Rotary Encoder. Black left push button “Up”, right push button “Down”. Red push button reset to end-of -travel.