Jason Zheng, Joey Mintz, Suzanne Yam, Leobeliz Perdomo Blanco External Sensors Lab
Group L-Instr. Professor Jayne Kim, GTA Anusha Mannava February 17th, 2016
Executive Summary
The External Sensors Lab is mainly about the AEV external sensors. Students will be able to recognize the external sensor hardware components and understand the use of each component. Also, students will learn and practice troubleshooting techniques, and program functions to operate the AEV control. The external sensors are known as the reflectance sensors and they consist of a single infrared LED and a small phototransistor on the red board. The function of Servomechanism (Servo) that is also given in the AEV kit is to provide control of velocity and acceleration by controlling Pulse Width Modulation(PWM). The servo that the students is using for their AEV can rotate from 0 to 180 degree.
The AEV behaved as expected on the track with little issues. That is, after all technical issues were overcome to get the AEV on the track and running in the first place. Given the technical issues out of the team’s control, time was not very plentiful, so the code used was not written to the exact objective of the lab. The team was able to understand how the AEV moved on the track after they got everything to work. A specific code can be written to accommodate to the movement of the vehicle to accomplish the task required. Specific values may need to be changed, but the overall code can be written to allow the AEV’s motion to be tracked.
The team encountered several difficulties with the AEV equipment during this lab. The first major problem was that the Arduino was not connecting properly to the computer that is usually used, so the team tried connecting it to two other computers but it did not work. Then the team had to use three USB cords and two Arduinos before the the Arduino finally connected to one of the computers and the COM port could be changed to COM7. Another big problem the team faced was that the sensors were not getting the correct readings. After restarting the program and servo code multiple times, and tightening the sensors onto the L-Shaped Arm with zip-ties the sensors were still not working properly so the sensors were replaced with new, working sensors.
Problem solving and testing are two very important processes that every engineer should be able to do. This lab enabled students to practice these skills and way of thinking to ensure that their AEV was working properly. Even though it is good for students to be able to learn about different topics by themselves it would be helpful if students could learn about the AEV before beginning brainstorming. Not all students in the College of Engineering have prior engineering experience. Also, it would be more beneficial to everyone if all the equipment were checked for flaws so that no groups fall behind detecting and overcoming errors.
Appendix
// Accelerate all motors from start to 25% power in 3 seconds.
reverse(4);
celerate(4,0,25,3);
// Run all motors at a constant speed (25% power) for 1 second
motorSpeed(4,25);
goFor(1);
// Run all motors at 20% power for 2 seconds.
motorSpeed(4,20);
goFor(2);
// Accelerate motor two from start to 27% power in 4 seconds.
celerate(2,0,27,4);
// Reverse all motors
reverse(4);
// Run all motors at a constant speed (25% power) for 2 second.
motorSpeed(4,25);
goFor(2);
// Brake all motors
brake(4);