RFID solution for cat feeder with 12" or greater range (and electric eye too)? Answered
I want to build a cat feeder that's basically a plexiglas box with a sliding door that will close whenever our fat cat gets near it, and re-opens when he moves away. Normally it'll remain open so our other two cats can eat (they're skittish so it's better if it doesn't have to react to them, and instead can react to the fat cat). To drive the door I thought I could use an old CD ROM drive (kind of like https://www.instructables.com/id/RFID-pet-feeder/). I'd like the tag on the fat cat's collar to be waterproof(able) and not require batteries. The antenna can be as big/complicated as necessary, as long as I can get the desired range of 12-24" or so. Any suggestions for an RFID setup that'll work for this?
Also, I should set up an electric eye around the opening so it doesn't activate (close) when a cat has its head in the opening. Something like we have on our garage door to prevent it closing on someone, but smaller would be ideal. Any suggestions?