I'm a newbie at Arduino and I'm trying to figure out if my project idea will work. I would like to have a system where I have several objects and they can tell when one is in proximity of another. So if I have Object A, B, and C, and I put A and C next to each other, it will send this information back to the board that A and C are close. I don't need to know how close, just a true or a false.
I have been looking through some of the available products and it seems like a couple things I could use are RFIDs or color sensors (if I make each one a distinct color). I can't really see how either of those things work though, so I'm not sure if they are plausible solutions.
I'm sure someone else must have done a project where they want to achieve this, so is there some known solution for this? A tutorial would be wonderful. Thanks!