At the beginning of the performance testing phase, before any testing had actually begun, the team added a servo brake to the current vehicle design. This brake worked by rotating upwards and coming in contact with the track such that the friction between the brake and the track would stop the vehicle. the rotating arm itself consisted of a small metal bar wrapped in medical tape. A picture of the first servo attachment used on the AEV is shown below.
Initially, this servo attachment did not rotate, regardless of the program being uploaded to the Arduino controller board. Once the servo and controller board were replaced, however, all components worked as expected. At this point, the servo brake worked extremely well, and was used throughout the completion of performance test 1. Before completing performance test 2, however, the medical tape was removed from the metal bar and replaced with an eraser. This was done because the medical tape failed to stop the vehicle immediately during one of the test runs, and the team believed the eraser attachment would perform better when braking at high speeds. An image of the eraser servo brake is shown below.
This new servo attachment worked even better than the previous one, and was therefore left unchanged in the final design. The only other modification made to the AEV before the final performance test was the addition of a magnet that could connect to the caboose. The magnet was placed at the front of the vehicle, and the Arduino controller board therefore had to be moved back towards the rear of the design. A picture of the magnet attached to the front of the vehicle is shown below.
As can be seen above, the Arduino controller board is far enough away from the magnet that it is in no danger of being ruined by its electromagnetic field. The final AEV design, with the new servo and magnet attachments, is shown below.
The total cost of construction for this model came out to be $166,870.