Am I right thinking I need to use a private code if I want to use the scanner? When I tried to wake up my phone with the scanner, it asked me for the code and I hate that.
At least a 4-digit passcode is mandatory when using TouchID. You will need to enter it whenever the iPhone is restarted, or if left in sleep mode for > 48 hrs. Also, it will ask for it if when there are more than 6 (iirc) unrecognized scans. Otherwise, no, it shouldn't ask if it also had a recognized scan.
fingerprint scanner Thanks for the answer, that's what I fought. I will think it over because of the code.