I am starting a project on creating a metal detector for my final year end project and I am not sure where to start, I have looked into PI and BFO and lots of schematics, however printing out a PCB and fitting the components alone will not give me many grading points. I must understand what I am looking at when looking at a schematic, was this design one of your own ? and if so how did you start ? also if you would be kind enough to link me any useful resourses on building a BFO or PI metal detector I would be very appreciative.

 

Here is a pretty good place to start, metal detector circuits about half way down the page - http://chemelec.com/Projects/Projects.htm