Hi John

Dallas Semiconductor's iButton devices are cheap and easy to use
www.ibutton.com
Use a PIC to read the buttons and enable/disable the machine somehow.
Log the ID and time reports from the PIC.


Cheers
Mark
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Mark Hull
Engineering/Technical
EMS (Africa) (Pty) Ltd
PO Box 1026, Melville, 2109, South Africa
Ph +27 11 482 4470 Fax +27 11 726 2552

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