With the combination of Arduino and Flash, we created an app to keep track of the amount of people who enter and exit a single room. Experimenting with Arduino for the first time presented many problems, however, it was quite the learning experience. The Guest Counter consisted of two LED lights and two PIR sensors. When the first PIR sensor was triggered followed by the second, the green light was turned on to signify that one person had entered the room. When the second PIR sensor was triggered followed by the first, the red LED light was triggered to signify that someone had left. In addition to the sensors, we created a visual display to showcase the amount of people who currently occupied the room.