A starting point for those building self-driving vehicles.
Building a line-follower is a popular initiation into the world of robotics. In the beginning, your creations follow the "line" and never deviate. In the end, when you master the craft, your AI-enhanced robot becomes a rebel, deliberately crossing the line of polite robot behaviour every chance it gets. Elon Musks's nightmare.
But it's a long way until you get there. To start simple, use Line Follower click, with its array of five QRE1113 miniature reflective object sensors. Each one consists of an IR receiver and transmitter, and each one has its own digital output to talk with the target MCU -- the robo brain.
Of course, all this talk of rolling robots brings the Buggy to mind. Somewhere down the line (pun intended) we'll make the Buggy and Line Follower click more compatible (currently the Buggy doesn't have a downwards facing mikroBUS™ socket which makes Line Follower difficult to implement -- but hey, we call it dream cars for makers and hackers, we're sure you can hack a workaround.)
But first, get introduced with the product. See the Libstock example. And see the short video which shows how the concept works: controlling speed with line thickness and using the width of the five adjacent sensors to gauge whether the hypothetical vehicle is on track.