This is a device driver that enables a single board computer (Raspberry Pi, Jetson Nano, etc) to access an LSM9DS1 IMU sensor. The LSM9DS1 combines a 3D accelerometer, 3D rate gyroscope and a 3D magnetometer. It's useful in robotics and other applications for measuring a robot's attitude and movement. The LSM9DS1 is made by ST Microelectronics. The datasheet is available from their website.
This is based largely off the hard work of Richard Gemmell (from over here: https://github.com/Richard-Gemmell/lsm9ds1-rjg). This version has simply added the scaled versions for the request functions (so you can get accel in g, mag heading in degrees, temp in f, etc), and collapsed it into a single file. We also added code to run a magnetometer calibration routing and configuration structure which can be passed into configure() method to calibrate the magnetometer. The run this routine:
python -m lsm9ds1.lsm9ds1
and follow the instructions. This is meant to be integrated into your machine configuration process, so you can call
poll_mag_calibration from whatever infrastructure you currently have. That routine is polling for mag gauss readings
so you should run it from it's own calibration thread. See the sample in the lsm9ds1.py code (the thing that runs
the example calibration routine).
- Connects with I2C or SPI (although the SPI is largely untested in this fork)
- Preconfigured for 230 Hz output data rate
- Converts accelerometer and gyro output to use the same axes as the magnetometer by flipping the direction of the x axis.
- Detects data ready in software or with an optional GPIO hardware interrupt.
- Not a complete implementation of the sensor's API.
If you don't check for data ready and just read data then you will miss some samples. Worse than that, in some cases you'll read part of one sample and part of the next. This provides plausible looking but incorrect data. You must wait for data ready before reading the sensor values. See the examples.