Our idea is to embed a sensor into a bust of a statue. To test how the sensor would interact embedded into a statue, we 3D printed several test casings. The bust itself was too large to print, so we only printed the piece with which the sensor with interact. We printed several versions of varying thickness and angles to test how the sensor would perform under different conditions.
The circuitry for passive infrared (PIR) sensors is fairly straightforward as you can purchase sensors mounted on printed circuit boards (PCB) that handle most of the work. When you enter the realm of PIR customization, you can enter fairly complicated territory quickly. To avoid some of the pitfalls, our PIR was set up with a potentiometer to control the sensitivity and relatively simple code that indicated to both the user and the designer when a player was sensed by the sensor. Beyond electrical engineering customization, we also played around with the use of different Fresnel lenses and the absence of a lens to get a good idea for how large of an area we wanted Medusa to be able to see at a given time.
For the purposes of testing our initial ideas and expanding how we can execute the gags in our room, these tests were a success. A combination of Fresnel lenses (or lack thereof) and different eye geometries allow you to fine-tune the range that Medusa can see at any given point. Additionally, the use of PIR sensors allows for some interesting mechanics with Medusa's ability to see players in the same reflections that she is using to try to hunt them. Our tests indicate that a PIR sensor paired would a properly-selected photoresistor could allow Medusa to identify both players and the lasers that allow players to kill her. We have proven that a PIR sensor (when properly ported to a smaller microcontroller) can be embedded in a mask or statue, and with the use of the mask geometries, one can customize the difficulty of the players' task.