Note: I completely redesigned the board, made them much thinner (0.8-mm-thick pcb) for easier mounting, and dropped the price to match the MPU9250 micro add-ons sold elsewhere on Tindie. It's a trifecta of value for you!

Wondering which motion sensor is right for you? Take a look here.

What is it?

LSM9DS0 9-axis motion sensor with 24-bit MS5637 pressure sensor mounted on a pc board that is to be soldered to the back pads (pins 23 - 34) of the Teensy 3.1 microcontroller.

This new design replaces the original LSM9DS0 Micro Add-On shield. The original lacked two features. Firstly, one of the interrupts was broken out to pin 33 on the Teensy 3.1 which is also the pin to enable the EZ-mode bootloader, making the interrupt pin unusable. Secondly, it lacked the tenth degree of freedom, namely a pressure sensor. I redesigned the LSM9DS0 Micro Add-On board keeping all the same LSM9DS0 interrupts broken out but with no signal routed to pin 33. I also added Measurement Specialties excellent 24-bit MS5637 pressure sensor which has a large range (200 - 2000 millibar) and can discriminate altitude changes to 13 cm. Even though the pressure sensor has a small 3 mm x 3 mm form factor, I had to use 0402 resistors and capacitors on the board to fit everything in. The 10 DoF LSM9DS0+MS5637 Micro Add-On shield works as well as the original but has more features and none of the limitations.

Why did you make it?

The LSM9DS0 is one of only a few 9-axis combination accelerometer/gyroscope/magnetometer MEMS sensors available today. It's in a small 4 mm x 4 mm package and has a lot of functions with a correspondingly large number of output and interrupt pins. I wanted to make use of the sensor for 9 DoF sensor fusion for motion sensing and motion control applications but do so with a very small footprint. The Teensy 3.1 microcontroller is a powerful Cortex M4 ARM-based microcontroller that is ideally suited for sensor fusion filtering. By designing a small pc board with the LSM9DS0 sensor that fit on the back of the Teensy 3.1, I can achieve absolute orientation sensing in a device package with an extremely small footprint with plenty of room (unoccupied pins) for expansion. The addition of a pressure sensor naturally complements the 9 DoF sensor fusion and is very useful for any application where altitude changes are expected, like quadcopters or RC helicopters, etc.

What makes it special?

This is the first example of the modular Teensy concept, where small special-purpose pc boards designed to be added on to the Teensy 3.1, either alone or in combination, can be mixed and matched for specific applications. You can see a picture of the first of these LSM9DS0 micro boards I ever mounted on the back of a Teensy 3.1 above. It still works and I use this Teensy as my workhorse for device testing almost everyday!

In the works are pc boards for the other two 9-axis motion sensors I know of, Invensense's MPU9250 and Bosch's BMX-055, as well as boards for LiPo battery charging, Bluetooth Smart, and dc motor control. Others are likely to follow. The idea is to add modular capability while maintaining an extremely small, portable, low-power package. More on the concept can be found here.

I have modified Jim Lindblom's excellent Sparkfun LSM9DS0 library to add 9 DoF sensor fusion using open-source Madgwick and Mahony sensor fusion filter algorithms, gyro and accelerometer calibration, accelerometer bandwidth specification, temperature readout, and i2c communication with the Teensy-3.1-specific i2c_t3.h Wire library. A general discussion of 9 DoF sensor fusion and motion control can be found here. The library to run sensor fusion on this LSM9DS0_MS5637 Micro add-on shield with the Teensy 3.1 is reposited here. This is a well-commented program that demonstrates most of the utility of the LSM9DS0 motion sensor and all the functionality of the MS5637 pressure sensor, which reports pressure, temperature, and altitude along with the 9 DoF absolute orientation obtained from the 9-axis motion sensor.

Teensy 3.1 can be purchased from OSHPark for $17 and is not included with your purchase of this add on.