A microcontroller-based method and apparatus are described for measuring motions signals (301) with a plurality of inertial sensors (302-304) contained within a device package housing and validating (420) a first measured motion signal (e.g., ΩX) by generating at least a first estimated value ΩX for the first motion signal (e.g., 419) based on at least a second measured motion signal (e.g., AY) and for comparing the first estimated value for the first motion signal (419) to the first measured motion signal ΩX in order to validate the first measured motion signal ΩX.