Overview

The LSM9DS1 is a 9-degrees-of-freedom (9-DoF) System-in-Package (SiP) motion sensor manufactured by STMicroelectronics. It combines a 3-axis digital accelerometer, a 3-axis digital gyroscope, and a 3-axis digital magnetometer into a single $3.5 \times 3.0\text{ mm}$ package.

Outputting 16-bit resolution data over $I^2C$ or SPI, the LSM9DS1 enables full 3D orientation tracking (heading, pitch, and roll) using sensor-fusion algorithms (like Madgwick or Mahony filters). It is standard equipment in robotics navigation, drone AHRS flight controllers, virtual reality controllers, and space/satellite payload tracking.

Quick reference

Pinout

Breakout modules expose a 10-pin or 12-pin 0.1" (2.54 mm) header:

Specifications

Dual $I^2C$ Devices in One Package

The LSM9DS1 contains two distinct $I^2C$ sub-devices inside the same silicon package:

1. Accelerometer & Gyroscope engine: Default $I^2C$ address 0x6B (WHO_AM_I register 0x0F returns 0x68).
2. Magnetometer engine: Default $I^2C$ address 0x1E (WHO_AM_I_M register 0x0F returns 0x3D).

Wiring

Example

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_LSM9DS1.h>

Adafruit_LSM9DS1 lsm = Adafruit_LSM9DS1();

void setup() {
  Serial.begin(115200);
  Serial.println("LSM9DS1 9-DOF test");

  // Initialize I2C mode
  if (!lsm.begin()) {
    Serial.println("Could not find LSM9DS1! Check CSAG and CSM pins.");
    while (1);
  }
  Serial.println("LSM9DS1 initialized successfully.");
  
  lsm.setupAccel(lsm.LSM9DS1_ACCELRANGE_2G);
  lsm.setupMag(lsm.LSM9DS1_MAGGAIN_4GAUSS);
  lsm.setupGyro(lsm.LSM9DS1_GYROSCALE_245DPS);
}

void loop() {
  lsm.read();
  
  sensors_event_t a, m, g, temp;
  lsm.getEvent(&a, &m, &g, &temp);

  Serial.print("Accel X: "); Serial.print(a.acceleration.x); Serial.print(" m/s^2\t");
  Serial.print("Gyro X: "); Serial.print(g.gyro.x); Serial.print(" rad/s\t");
  Serial.print("Mag X: "); Serial.print(m.magnetic.x); Serial.println(" uT");

  delay(200);
}

Common mistakes

• Leaving CSAG or CSM floating: Leaving either Chip Select pin unconnected drops the corresponding sub-device into SPI mode, making address 0x6B or 0x1E unresponsive over $I^2C$.
• Not performing magnetometer hard-iron calibration: Nearby metal, battery leads, or PCB ground planes induce static magnetic offsets. Software calibration must compute offset vectors ($V_x, V_y, V_z$) to center magnetometer readings.

Notes

• LSM9DS1 vs MPU9250: The LSM9DS1 is STMicroelectronics' primary competitor to the InvenSense MPU9250 9-DoF IMU.