Better unlocking schemes? On my Galaxy S3 I have only a few options for locking/unlocking:

Either no locking and swiping, or entering a pin every time. Both options are not very attractive. One is too insecure when leaving it somewhere, the other too cumbersome, when I just take it out of my pocket. OK, there are more options, like face recognition and all that, but it never works in the dark.

What I would like to have is a more intelligent scheme: That I do not have to unlock as long as my S3 stays close to me. That a pin is only required, when it is further away from me.

Is something like that available or possible?  Maybe in conjunction with an RFID-chip? Or bluetooth? So I would carry in another pocket that other device.
Maybe you're looking for something like NFCSecure.
You can combine normal lock screen (i.e. swiping) with an underlaying NFCSecure lock screen for better security (only lets you in when scanned the needed NFC tag).
Your smartphone needs NFC capabilities and you need an NFC tag to carry around with you to unlock your phone.
Can not test this as my phone doesn't have NFC capabilities.