This is one of the projects I had most fun with at University. I had just learned about the existence of the Arduino board and was really excited about the things I could create with it.
The project had only one requirement: that all students used at least two different interaction methods (keyboard and mouse not counting, since they are too simple). The theme of the project was completely free.
In my project I used LEGO pieces connected to a 180º servo to produce the movement as the first interaction method. And the OpenCV library in order to identify users’ faces as the second method, which turned out to be most challenging.