Using the Parallax Serial RFID Reader with the Raspberry Pi

I’d originally purchased the Parallax Serial RFID Reader several years ago with the hopes of resurrecting an old automatic cow feeder we have lying around on the farm. The original 1980’s era feeder used proprietary transponders attached to the cow’s collar, and when scanned would dispense a preset grain ration a couple times per day. We don’t have any of the original collars around the farm, so I thought it’d be a fun project to replace the old scanning system with a Raspberry Pi based solution.