Main problem with any accelerometer is that free fall acceleration is an additive component in the measured acceleration. Free fall acceleration presents the Earth direction. Meanwhile applications require Earth direction and dynamic motion information in decomposed form. Especially in harsh conditions. Invensense MPU6050 sensor data was processed with 16MHz low energy NRF processor. Filter consumes 10kB of RAM. The filter response is from 1millisecond to 5 milliseconds and its performance is confirmed by analogue accelerometer ADXL 335 and oscilloscope with threshold detection code. Max shocks tested were +/-16g, and max rotation speed tested +/-2000degrees/s. Sensor fusion method: maximization of likelihood, which is a special case of more general principles of maximum relative entropy. Constraints used: free fall acceleration nominal value of 9.812m/s^2 and gyro and accelerometer formulas. Author: Assoc. Prof. Renaldas Urniezius, Dpt. of Automation, Kaunas University of Technology.