hi you can find very good files and information about "metal detectors" in below. this is "HEX" file (Demo version). for its FULL schematics, PCBs and HEX file, email me. this project worked with 8051 and already produced by FAP Company! but [move]NOW YOU CAN fabricate it, yourself!!![/move] FAP Company: http://www.fap-company.com for detailed information, EMAIL me! in the hope that you can use this product. with best regards :D metal_detector.rar