While there has been lots of cutting and 3D printing to do, Phil had also agreed to code the line follower challenge. With TractorBot I we had experimented with the Open CV computer vision software but the results were disappointing. However, with Pi 3 power we thought we might be able to get a Pi Camera to perform the line following duties at reasonable frame rates. Initial trials were encouraging and Keith designed a servo controlled camera case for the front of TractorBot.
The idea being that when the line follower choice was made from the menu, the servo would activate and the line would be illuminated by a Blinkt in the nose. After a few attempts and a lot of tuning we were happy with the result. https://youtu.be/Yrbg0VhtKmk
This is a graphic (sorry) illustration of how far the Pi has developed in just a few years.