i am trying to build a metal detecting robot. i do not know anything about them but i used to do a lot of programming
so i just took a self propelled mower, took off the blade. i make it go in an ever-decreasing-circle. I paid a local electrical engineering company to interface to my metal detector thru the headset. When the headset goes off, it activates a signal which activates a solenoid to paint a spot on the ground where the metal is.
I can completely cover an acre or 2 in an hour. I use a second detector and go around the edges.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/rambling-robot
But you should take a look here at Gareths bots, Thunderbird 6 and TB-007. It uses a metal detector as well, but I don’t think he added the spray paint, which is a good idea.