Connect :

• Teensy D0 to SCL
• Teensy D1 to SDA
• Teensy VCC to VIN
• Teensy GND to GND

Install Teensyduino

Then, add thoses library to IDE :

• L3G Libray 1.2.2
• the ‘older’ LSM303 Library 1.4.4

Load one of the following code :

• https://github.com/paulgreg/headtracking-from-kris : based on Kris code but with minor changes (fix and comments)
• https://github.com/paulgreg/headtracker : a "from scratch" version

The chips needs to be calibrated. Otherwise, result won’t be good.

• Clear your desk off, move away any metal object.
  To be sure that you’ve got no perturbation, you can use a traditional compass.
• Connect your head tracker with a nice long USB.
• Load the Calibrate sketch from LSM303 LSM303 1.4.4 library in menu : examples > LSM303 > Calibrate (https://github.com/pololu/lsm303-arduino/blob/master/LSM303/examples/Calibrate/Calibrate.ino).
• open Serial Monitor.

• Rotate your IMU slowly 360 degrees in the X, Y, and Z axis.
  I usually start flat on the table and rotate 360 - going slow about 10 seconds.
• Then without jarring (NO high G load) I slowly pick up the IMU and rotate Left to Right 360
• Then Front to Back... You are trying to get the device to "see" magnetic north in every orientation.
• You'll notice the MIN / MAX on the serial output will begin to settle out.
• Copy paste those numbers to the top of the code "headtracking-from-kris" :

#define compassXMin -###.0f
#define compassYMin -###.0f
#define compassZMin -###.0f
#define compassXMax ###.0f
#define compassYMax ###.0f
#define compassZMax ###.0f

You can then test the device with jstest-gtk

When trying it, be sure to be far away from metal. Even a small metal object has a big influence on sensor !

Box was made from a visiting card box that I cut to make it smaller.

I first use screws to mount it inside but breakout is extremely influenced by metal. So I used a hot glue pistol to fix it inside the box.