my line following code for arduino (it also has a drag race mode) it was made to participate in the UKmars competition it is for a robot that uses led sensors and an arduino nano circuit board (although you could probably run it on other boards like the uno) it is written in arduino(nearly C) and i recommend you use the arduino ide to run it, as it uses some things such as millis() that do not come in normal C. It is fairly simple and should be easy-ish to edit for your own needs with some knowledge of C or C++ There is now an organisation for this, this version is old and I am to lazy to update it