This project is perfect for student experiment, not so complicated but very interesting. It is a metal detector that uses utilizes two oscillators that produce radio frequency.

Radio frequency (abbreviated RF, rf, or r.f.) is a term that refers to alternating current (AC) having characteristics such that, if the current is input to an antenna, an electromagnetic (EM) field is generated suitable for wireless broadcasting and/or communications.

Radio Mobile is a free RF design software that was originally created for amateur radio applications but can also be used for commercial radio systems design. It was developed and continuously being developed by Roger Coudé (VE2DBE), an amateur radio enthusiast.