The present invention relates to an attitude detecting device requiring no optical nor visual sensors but instead using an advanced processing method, which can be used in applications such as data-login, measurements, motion control, cursor pointing on graphic user interfaces, gaming, etc. The device includes inertial measurement units (IMU) such as accelerometers, gyroscopes and may also include magnetometers. The method utilizes the IMU's sensor data and uses a revised method to transfer 3-dimensional rotations into a representation, such as quaternions, Euler angles, yaw, pitch, and roll. The method also provides better performance when the device recovers from interrupts. The method further utilizes the above mentioned representation and turns it into 2-dimensional values in a precise way while intentionally remove the effects caused by rotation in the other unused degree of freedom.