I built this in the fall for a class called Digital Electronics.
It is supposed to be a wearable navigational unit. It uses an Arduino and a GPS module to calculate if the user is moving closer to or further away from a set destination, programmable to any X and Y coordinates. If the user is getting closer to the destination, the bubbles begin. If the user starts to get further, the bubbles turn off. The user must then wander to find the correct path.