I need help converting this project to reality for my office that I currently work in. I basically want to have sensors(idk which or what kind) behind a bookshelf in individual racks and have those sensors communicate with an app to tell if that rack is full or not. I have no background in programming or robotics but I am willing to learn and read as much as possible if someone can guide me in the right direction it would be really helpful. I also wan it to be as cheap as possible.
I have attached an image of how I want the setup to be. Thanks in advance