How do those walk-through scanners in libraries know if you’re taking a book without borrowing it, especially if those books don’t have metal inserts or anything like that?

Question

How does the library borrowing system work? and how come even if there is no obvious metal insert in the book those gates still know when and when not to beep if the book has or hasn’t been borrowed?

In: Technology

Answer 1

> especially if those books don’t have metal inserts or anything like that?

Because it DOES have metal inserts. They are called RFID chips, and they are very small and very cheap. You can even buy them. I suggest google image: “rfid chips label and tags”