STMicroelectronics Sensors

Accelerometer selection depends on: Full-scale range - ±2g for tilt/static, ±16g for motion/impact

Resolution - 12-bit for basic, 16-bit for precision

Output data rate - match your application requirements (1Hz-6.7kHz)

Interface - I2C for simple, SPI for high-speed

Power consumption - critical for battery applications

Special features - pedometer, free-fall detection, tap sensing. ST offers LIS2 series for basic applications and LSM6 series for combo sensors with gyroscope. Consider combo sensors for space and cost savings in multi-axis applications.

Define your acceleration range and power budget first. Consider combo sensors for multi-axis needs.

Accelerometers measure linear acceleration including gravity, enabling tilt sensing, motion detection, and vibration monitoring. They cannot distinguish between gravity and actual acceleration without sensor fusion. Gyroscopes measure rotational rate (angular velocity) around three axes, enabling orientation tracking and rotation detection. Gyroscopes drift over time and cannot sense static orientation. For complete orientation tracking, both sensors are typically combined with sensor fusion algorithms (complementary filter or Kalman filter). ST's LSM6 series integrates both in a single package.

Use accelerometer for tilt and motion. Add gyroscope for orientation tracking. Use combo sensor for both.

Minimize sensor power through: Lower output data rate (ODR) - power scales with sampling frequency

Use low-power modes when full performance isn't needed

Enable auto-wake/sleep features for intermittent monitoring

Power down unused axes

Use FIFO to batch data and reduce MCU wake frequency

Select appropriate full-scale range (higher ranges consume more power)

Consider combo sensors with shared power management. ST sensors offer multiple power modes with current consumption from a few uA to several mA depending on configuration.

Optimize ODR for your application needs. Use FIFO and auto-wake features for battery-powered designs.

Sensor fusion combines data from multiple sensors (accelerometer, gyroscope, magnetometer) to provide more accurate orientation than any single sensor. Accelerometers provide absolute tilt reference but are noisy

gyroscopes provide smooth rotation data but drift over time

magnetometers provide absolute heading reference. Fusion algorithms (complementary filter, Kalman filter, or ST's MotionFX library) combine these to provide accurate, drift-free orientation. You need sensor fusion for: 3D orientation tracking, gesture recognition, image stabilization, navigation systems, and VR/AR applications.

Use ST's MotionFX library or similar for sensor fusion. 9-axis fusion (accel+gyro+mag) provides best accuracy.

ST MEMS sensors support I2C (up to 400kHz) and SPI (up to 10MHz) interfaces. I2C is simpler with 2-wire interface (SDA, SCL) and supports multiple devices on same bus. SPI offers higher speed with 4-wire interface (MOSI, MISO, SCK, CS) and is better for high ODR applications. Most sensors use interrupt pins (INT1, INT2) for event detection (data ready, threshold crossing, free-fall). ST provides drivers and example code for STM32 platforms. Register maps are consistent across ST sensor families, simplifying software development.

Use I2C for simplicity and multiple sensors. Use SPI for highest data rates. Use interrupts for event-driven applications.