Here is the current code, information and files for my Sainsmart 4WD robot build. The code is not optimized whatsoever but functions well enough at this point. So many people have asked for the code due to troubles- I decided to post it here. You will need to modify the code to suit your setup and connections but this should provide a baseline for anyone struggling with their robot. Good luck in your build. If this helped you please consider leaving a comment or thumbs up on my YouTube videos. There are several covering much of this robot build. For future updates please consider subscribing. I ask 2 things of anyone who uses this: Updated code an instructions:http://blog.mkme.org/index.php/arduino-sainsmart-4wd-robot/Channel:https://www.youtube.com/user/Shadow5549 This robot build and my other Arduino videos:https://www.youtube.com/watch?v=Bpht2otFoF4&list=PLxyM2a_cfnzh9sbbEMFvFAGvNKfSElkvC Another:https://www.youtube.com/watch?v=sztUkGO6Fuo Unboxing:https://www.youtube.com/watch?v=BD3JAdnVosg&list=UUTo55-kBvyy5Y1X_DTgrTOQ Most recent Video:https://www.youtube.com/watch?v=7sN_mxAh7Og Cheers! Note: If you are here due to a high level of frustration with the programming, hardware and/or components- fear not. You are not alone. Check out the below vid (no link so as to not say bad things about anyone's products). I just about went crazy when I first built this thing- It DOES get easier. Hence me sharing the code ;) Youtube: watch?v=7U4yzxh0IMQ&list=UUTo55-kBvyy5Y1X_DTgrTOQ Update V9 Code: Updated to better deal with corners and direction changeSimply edit the code to suit your pin configuration and comment out any items you don't want to include. From there you should have a decent base to develop your robot from! Mount for distance sensor servo and sensor itself can be found on Thingiverse- links to be updated. If you get your robot working using this code or any mods/info found here- please share with me via YouTube. I would be truly excited to see your creation. Cheers