Thursday, February 16, 2012

Ball Bot Video Guide

Here is the finished Ball-Bot. This video was shot during our senior design project final presentation at Southern Polytechnic State University. I would like to thank Dr. Chan Ham for being our mentor and guiding us every step of the way. Ball-bots are also frequently made with Mindstorms NXT Robots from Lego. It is the easiest way to build your own Ball-bot without spending too much time doing your own custom fabrication and calculations. The research for the Lego ball-bots is publicly available allowing anyone to replicate the Lego ball-bot. All the kinematics are derived, and it is modeled as an inverted, spherical pendulum.

You can find more details in the blogs at the bottom of this page.

Here is the wheel base assembly. We're testing the response of the motors to the motion of the inertial measurement unit (IMU).

The IMU is comprised of the ADXL345 accelerometer and the IDG500 gyroscope, and they are connected to the Arduino Mega 2560. Therefore, the Ball-Bot is able to measure angular velocity, from its tilt angle, as well as acceleration in the X, Y, and Z directions. The Z direction shooting up from the center of the basketball out through the top of the vertical aluminum structure.

Here is a video that shows how the ADXL345 accelerometer is used with the Arduino Mega 2560.

Of course, I can't leave out the IDG500 gyroscope.

By testing out each of the two individually, we were able to breakdown a big challenge into smaller challenges. This mindset and strategy is what helped our undergraduate group complete such an ambitious task in only one semester. One big problem is just a series of smaller, more manageable problems. When you complete small goals along the way, it also helps keep you motivated and less overwhelmed.

After we got the ADXL345 and IDG500 working individually, we made the IMU prototype board as seen here:

I will divulge more of our secrets soon. Please leave comments below with any questions or suggestions. Thanks for reading my blog, and good luck with your projects! Beginners, don't forget to check out Lego Mindstorms NXT Robots for the easiest way to get started building a ball-bot of your own.


  1. Great job on this guys! I would love to read your research paper -- I will download it!

  2. Great! Let me know if you have any trouble. Just leave a comment here because it goes straight to my personal email. Enjoy!

  3. Can you load the code end schematic?
    I don't say the English. Excute for the linguage.

  4. hey, I'm doing the same project for my capstone. I'm wondering about the motors that I should use. Hope you have some guidance and experience???

  5. I have kinda the same question about the motors... Although I ended up ordering 12v 150rpm dc motors, hope they'll do. Also what kind of omni wheels did you use?

  6. Can you help me sending te code from


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