Pulse induction metal detector using Raspberry Pi Pico board ( RP2040)
...This pulses are amplified and applied to a MOSFET device that had the searching coil in series with drain. The pulse will produce a magnetic field generated by the searching coil, and becose of eddy currents, the target will produce a very low corresponding voltage at the coil terminals. The mode this signal decay depends of target characteristics ( form, type, material ) and the distance. This is the signal we need to analyze, so it is supressed by two antiparallel diodes and passed to an operational amplifier . After amplification, the analog signal is read by one of analog input of Raspberry Pi Pico board and is analized by the software. ...