The BMI270 is a 6-axis inertial measurement unit (IMU) from Bosch in LGA-16 (2.5×3.0×0.83mm), combining a 3-axis accelerometer and a 3-axis gyroscope. The accelerometer uses a capacitive MEMS sensing element: a proof mass suspended by silicon springs moves relative to fixed electrodes under acceleration, changing the capacitance. A sigma-delta C-to-V converter digitizes this capacitance change at 1.6kHz ODR. Full-scale ranges: +/-2g, +/-4g, +/-8g, +/-16g with 16-bit resolution (0.06mg/LSB at +/-2g). The gyroscope uses a vibrating MEMS structure (tuning fork): the Coriolis effect causes a secondary vibration perpendicular to the drive vibration when rotated. The amplitude of this secondary vibration is proportional to angular rate. Full-scale ranges: +/-125, +/-250, +/-500, +/-1000, +/-2000 dps with 16-bit resolution. The built-in feature engine provides hardware-accelerated algorithms: step counter (pedometer), step detector, any-motion detection, significant motion detection (for Google Activity Recognition), wrist-wear wake-up, and tilt detection. These run autonomously at 0.5mA without MCU intervention. The programmable interrupt engine routes events to INT1/INT2. FIFO stores up to 2048 bytes of sensor data, reducing MCU read frequency and bus traffic. Power consumption is 0.65mA in full 6-axis mode.