I'm an interaction design student and doing a prototype class and we're using Arduino UNO and I need an advice. My initial idea for a project was to create stickers which you stick on items you don't want to forget to put inside your bag. I need to create a physical prototype for it using Arduino. Since stickers are too small to work with Arduino, I have constructed a physical bag prototype, and I need to Arduino to sense something was put in/outside the bag and give an indication. I'm thinking of using RFID, but unsure that's the right solution. I'd be happy to get your opinion about it.