Gyroscopes can measure rotations. It would be great to make such measures easily accessible to response latency experiments. I now managed to connect a gyroscope to my PC via an Arduino. I used components from Seeedstudio: a Xadow Arduino main board, a Xadow 6DOF unit that has an accelerometer and a gyroscope, an additional breakout board to connect an additional pin, and software from ic2devlibs.
Below are some photos showing how the “head” on the screen responds to rotation of the sensor (which is placed on the small white board in my hand). Next to the head, the rotation angle (up vs. down pointing of the nose) is displayed. This can easily be saved along with timestamps. There is also a video displaying the connection.