Toroid wound flux gate magenotometer

I am doing a project to measure small changes in the Earth's magnetic field. I need to make quite a few toroid wound flux gate magenotometers. Does anyone have a specific parts list / schematic that will work with an R3 Uno?

Thank you very much!

Sam

I found this document: http://www.invasens.co.uk/FluxgateExplained.PDF

And this:

If you use the latter design, credit the author of the report, if you are doing it for commercial gain,
contact the authors first...

Thank you!