I am working on a robotics application that involves moving objects (e.g. books) between several (around 10) stacks. To measure the performance, I'd like to be able to measure which book is located on each of the stacks. The order is not important I just want to know if a book is on one of the stacks.
The stacks are separated by at least one meter and the height of the stacks is less than 30cm (< 8 Books).
If have thought of putting an RFID card in every book and fixing RFID readers above (or below) the stack positions. Several readers could be attached via SPI or I2C to some arduinos or RPis.
What to you think about this approach? Is there a simpler way? Could someone maybe recommend a sensor that could solve this problem?
// Update: I can modify the books (e.g. add a QR-Marker) to some extent, but can't guarantee that the orientation on the stack is fixed.