I have a robot mower which cuts my lawn up to a border wire, leaving 20cm outside the wire uncut.
I would like to design a buggy to trundle round the border following the perimeter wire carrying a head salvaged from a conventional cordless trimmer.
My question is how to best sense the border wire which I laid in a cut in the lawn about 2-3 cm deep (as recommended by the mower manufacturer) and this steer the buggy keeping it central on the wire.
The loop wire has a voltage of about 30v on it and a resistance from end to end of about 10 ohms.