May I suggest a slight variation.

If you are building an Antinet, write your cards out as usual.

Make, using rocket books resources, a rocket book page frame to place around your note when finished. By printing out and cutting out the center.

Add ## before and after ## your index code. Say ##5310/2##

When the app scans the contents it should recognise the info between the # symbols and use it as a file name.

Send it to Dropbox or Google drive, whatever, and you should have a digital copy of your paper based Antinet. If your hand writing is better than mine it may even be searchable due to OCR.

Incase of fire or some such disaster, you can print each file back out on 4×6 paper or card.

Please note however your images may prove to be space hungry on your Dropbox.