When using the Lego EV3 I was frustrated with the sensors available and set about building my own.
Using an Arduino Mini and a LSM9DS0 sensor I have been able to built a 9 axis sensor that interfaces with the Lego EV3 software.
The available parameters available are Pitch Roll in Degrees, Heading in Degrees, Rate Gyro in Deg./S, Accelerometer in G, Magnetic Field strength in Teslas.