Initial implementation of a 9 DOM/DOF MARG IMU orientation filter with ADXL345, ITG3200 and HMC5843 on Arduino
I spent the last days creating an initial implementation of a 9 Degrees of Measurement (DOM) / Degrees of Freedom (DOF) AHRS sensor fusion orientation filter. I've created a library, called FreeIMU, which polls data from the ADXL345 accelerometer, the ITG3200 gyroscope and the HMC5843. Have a look at the attachments for my circuit schematics.
To access the ADXL345 accelerometer I used this nice Arduino library (based on this other one), while for the ITG3200 I used Filipe Vieira's ITG3200 Arduino library. To access the HMC5843 I used my library.
The sensor values are then pushed into Sebastian Madgwick's implementation of Mayhony's DCM filter incorporating Sebastian's magnetic distortion compensation (Algorithm available here - project here).
IMPORTANT: This code doesn't disable the ATMEGA internal pullups so a logic level converter/translator is needed if you don't want to fry your sensors. In the video I used a modified version of twi.c (inside of the Wire library) commenting out the pullup enabling in twi_init().
The result can be seen in the video below. Note that all the code published here is still very very young. You'll probably find lots of bugs and WTF but I think it can still be useful. Keep an eye on this website for the next developments. If you are working on this stuff get in touch with me if you want to share efforts.
|FreeIMU breadboard Schematics||11.86 KB|
|Arduino Code for 9DOM sensor orientation filter||31.11 KB|
|Processing Code for 9DOM sensor orientation filter||36.88 KB|