Buggy, Proto click, mikroC, and a little bit of woodworking.
First he showed us how to run the Buggy on Arduino code. Then he explained how to turn it into an obstacle avoiding robot. Now, Teo from the microcontroller projects blog built a Line-follower car out of our four wheeled development platform.
Out of the three, this one modifies the Buggy the most. Without going into too much detail, we'll just say that the project involves a third party line follower sensor and a bespoke wooden spacer.
The spacer Teo built is quite representable. But there are many ways you can go about it. To remind you, this is not the first time we've seen the Buggy customized.
In any case, the spacer you must figure out yourself. The code you can pretty much copy paste from the Microcontroller-projects blog. But best go through it line by line, to find a way to improve it. Just in case you run into Teo on a Line Follower competition.