Hey everyone. So recently I’ve started working on a new project, being a display case for “infinity stones”, similar to what was seen in the most recent avengers movie. The plan is to have 6 sockets I could place each stone in to, the arduino would then recognize which stone is in which socket, and then it would light up an RGB according to which stone is in that socket. Once all six stones are in place then the RGB’s will run through all colors at a high rate for a couple seconds to resemble the infinity gauntlet when all six stones are collected. The issue I’m running in to is how to uniquely identify each stone while on a budget. I’ve tried using an LED and photoresistor in hopes that a difference between the stones could be recognized, but unfortunately they all have about the same opacity. One idea I had is to cast my own stones in resin, with a resistor on the inside and small prongs coming out the side so I could measure the unique resistance value of each stone, but that’d be a lot of effort for still having pieces of metal coming out of the sides. Right now I think the idea is to measure the unique length of each stone using a potentiometer, a linear gear track, and arms to hold the stone in place. but this still seems like an overly complicated system. Can anyone think of a simpler way to reliably identify each stone with as little modification to the stones as possible?
P.s. the “stones” I’m using are little decorative rocks from the base of a fish tank (obviously im very on a budget here, but hey they look decent-ish)