Pulse induction metal detector with DSP

[bernte_one]

Hello,

a time ago i found this site from Lammert Bies.
Does someone know if the Project was ever finished with complete schematic an Firmware?

http://www.lammertbies.nl/electronics/PI_metal_detector.html

regards

[mohandes]

Hello,

a time ago i found this site from Lammert Bies.
Does someone know if the Project was ever finished with complete schematic an Firmware?

http://www.lammertbies.nl/electronics/PI_metal_detector.html

regards

thank Bernete
it is my big question .Damping R related to resistance or inductance coil??or related both of them?(think we use irf740 or irf840)
regards

[bbsailor]

thank Bernete
it is my big question .Damping R related to resistance or inductance coil??or related both of them?(think we use irf740 or irf840)
regards

The simple answer is: the value of the damping resistor is related to the amount of energy in the flyback pulse the needs to be damped in the TX circuit to allow the earliest sampling. The total amount of capacitance in the TX circuit includes the coil (wire turn to turn capacitance and coil to shield capacitance), coax cable and MOSFET COSS value. Higher damping resistor values typically represent lower TX circuit capacitance and/or less flyback energy needing to be damped.

At low delay values (near and below 10 uS), lingering eddy currents in the coil wire may be detected as targets so tinned stranded wire and Litz wire are used to minimize this problem.

I hope this answers your question.

Joseph J. Rogowski