The Razor 9dof would do all this calculations:
Direction Cosine Matrix (DCM) based Attitude Heading Reference System (AHRS) with gyro drift correction based on accelerometer (gravity) vector and magnetometer (compass) vector.
I have binary messages over serial: [type:length in byte]
[DIYd:4][ID:1][roll:2[pitch:2][yaw:2][checksum:2] => 13byte
But how to request data on demand? just send a byte to the Razor and respond?