Thanks. I guess, from reading what "they" provided, it seems possible that I might, from the view of the Arduino, have it tell me which # print it is? And then have my own list of "valid" numbers vs what the sensor can/might provide? It looks like I can make the request as either 1:1 (does this print # match the print you're looking at?) or 1:N (what number does the print you're looking at match?). If this is a correct interpretation, I might be able to have a limited number of enrolled prints (say six or seven) out of the ~170 available, with the numbers scattered out. Now the safe cracker has to figure out what to use, before "I" say "bugger off, at least for 10 minutes". Of course, I wouldn't tell him that, I'd just keep letting him try numbers. Of course, every failure just restarts the timeout clock.
But, given the availability of the RFID/NFC reader, why not use both? Then I've got "what you have" and "what you are". And I could toss in "what you know" (password/combination/etc) and feel pretty darned secure. Except for the oxygen lance that the guy brought in
. Not that I know anything about that