...was actually really easy. I'd build RFID reader plaques for the Castle for previous Halloweens that were owl-themed, but this year we wanted to do something different. In a collaborative session Shiloh suggested using these cheap plastic skulls I bought a bunch of from Dollar Tree for a gag I didn't end up making, and making those into the RFID readers. What a great idea! It was really fun making readers from these skulls. I just cut the plastic skulls from Dollar Tree in half, put in 10mm RGB LEDs into the eyes, and wired them to where the red/green LED on the RFID reader was attached.
The RFID reader kits from Amazon, $15.
The RFID reader board was removed from the housing, the red/greed LED was desoldered, and the blue and red pins of the 10mm RGB LED "eyes" were wired in place. From there the receiving antenna loop was hot glued into the top of the skull, and the circuit board was glued on top of the back of the RGB LEDs. Then the whole thing was attached to a piece of cut acrylic that was covered with themed fabric, and voila! The Dis de los Muertos-themed RFID readers were ready for Halloween week at The Castle.