This was done for a 2D (a term peculiar to my school meaning: across subjects) project for my university course Systems & Control (PID basically), at Singapore University of Technology and Design.
We were required to record and upload a video recording to YouTube. Basically it's a line-following robot with 4 IR sensors and motors (for wheels), where the wheel speed and direction is determined by a PD error function, subtracting left sensor readings from right sensor readings to give the error value, where 0 = white and 1000 = black for raw sensor values. This error function is fed into a simple PD (no Integral) function to give the calibration number (negative or positive) subtracted and added to the left and right (base motor speed) wheels respectively. An additional All White logic is added because the error function can't tell the difference between equal black values (detect black lines on both sides) and equal white values (detect white paper on both sides), where this All White logic (activated when sum of sensor values is below a certain threshold) saves the previous loop's left and right motor speeds and freezes the robot car in this state (e.g. keep turning right; keep pivoting left) until the sensors find enough black tape to surpass the white threshold, when PID behavior resumes to normal. This All White logic is critical in helping the robot nail 90 degree turns, which often give the problem of reading all white very quickly (thus under normal conditions would make the robot go straight out or go haywire).
This track is based on one of the Bowser's Castle tracks (unfortunately I couldn't find the original track again after searching the wiki), modified for our paper dimensions. This track is actually pretty challenging (I sketched it and laid out the black tape) and would be very difficult to do at a higher base car speed. The intersections are not difficult but are dangerous if the car doesn't stabilize by the time it reaches an intersection. Some lines are intentionally put closer together for added challenge, while the Y-junction at Robo-Browser was taken from the original track, to my surprise it works well at giving the illusion of an autonomous choice (left or right) to the car, which originally I thought would follow only the left or right leg programmatically. The Y-junction also gives us problems because it can often cause our car to turn around through the other leg and go backwards facepalm. Bowser's Fire is unstable in general but we got lucky this time, because usually if the oscillating motion sways the car to the right at the start of Bowser's Fire (notice the closest curve there) the car will take a shortcut to Boos Arena (I don't think this is allowed per the project rules but heck yeah for actual racing games). You can see this shortcut happening in our fourth lap though (we got a cheater here..).
Actually there's only some requirements we needed to complete for our custom designed tracks: two 90 degree turns, 30 cm discontinuous lines, total 8 turns, the whole track length spanning minimum 8 meters (ours about 10 m). No intersections or Y-junctions required or even the whole Mario Kart theme. We just wanted some challenge and some fun wink wink. To get an A grade for this project the car must run the track for at least 3 minutes and at least 3 laps. We didn't have to submit the Arduino code as well so technically it's possible to hardcode certain things.
Disclaimer: Siti Nurbaya, my groupmate, has already uploaded an earlier version that she edited, on top of which I inserted the place names and pictures to make it livelier. Of course kudos to the Nintendo dudes for most of the creative assets. Please spare us any criticism about the project 🥺 (it's just a school project).
Raw footage recorded by my awesome groupmate Li Jiang Yan Special thanks to Siti who edited the earlier version, to Kelvin Ng Chao Yong for his Malaysian Arduino code and testing, to Johannes Brian for the mechanical equipment and assembly of the robot car.