This project is no longer maintained as I will instead focus on a Balancing robot kit, the Balanduino. For more information see the new repository: https://github.com/TKJElectronics/Balanduino and the Kickstarter campaign: http://www.kickstarter.com/projects/tkjelectronics/balanduino-balancing-robot-kit.
The code is released under the GNU General Public License. Developed by Kristian Lauszus
This is the code for my balancing robot/segway. It's made for the mbed board, but can easily be ported to other microcontrollers like the Arduino - see the Arduino version of the code: https://github.com/TKJElectronics/BalancingRobotArduino.
The code is also published on the mbed site: http://mbed.org/users/Lauszus/programs/BalancingRobotPS3.
I use a 6DOF IMU from Sparkfun, I only use 1 of the gyro axis though. For more info about calculating the pitch and the Kalman filter see my post at the Arduino forum: http://arduino.cc/forum/index.php/topic,58048.0.html.
To steer the robot, I use an Arduino with a USB Host Shield on top together with my PS3 Controller Bluetooth Library for Arduino. The code for the remote can be found at my other repository: https://github.com/TKJElectronics/BalancingRobotRemote.
For information about the hardware, see the wiki: https://github.com/TKJElectronics/BalancingRobot/wiki/Hardware.
For more information see my blog post at http://blog.tkjelectronics.dk/2012/03/the-balancing-robot/ or send me an email at: kristianl@tkjelectronics.dk.
Also check out the Youtube video of it in action: http://www.youtube.com/watch?v=N28C_JqVhGU.