Fabrication example: A wooden bird's house that contains all components, Nfc tags woven in "birds".
Project site, documentation, how to's and DIY instructions can be found on github.schallbert.com. Repository is under LGPLV2.1 license
RAM usage of >75% will likely cause segfaults (been through that!) When battery powered, I'd propose to use a bi-stable relay or TTL so the System can keep alive without continuously using power for relay coils and - when finished - cut its own power supply. Only tested 1k Mifare Nfc tags, 4k and Mini will also work, Ultralight SHOULD work (but not integration tested).