< Main : High Level Design : Program Design : Hardware Design : Design Issues : Conclusion : Appendix >

# ( Results )
After an arduous month we met our goal: to build a robot that can detect and follow light. The finished product did not stray far from our original vision, which is very satisfying. The robot is very easy to interface, since anyone with a flashlight or lamp can use it. Although we had to remove extra features, we were able to include calibration and variable speed. The robot is also very responsive to the light around it. In fact, it was so responsive we had to take measures to decrease responsiveness. In the beginning we were unsure how well the sensors would work during the day, but the LDR's proved to be very effective. A user can shine a flashlight about two feet away in the presence of daylight and LightRover will still respond correctly. Ideally, the user should be about a foot away. Finally, the wheels perform much better on a smooth surface, such as a tabletop or in the halls of Philips than on carpet. See below for a video of LightRover in action.
Video (AVI): LightRover in action
# ( Conclusion )
We worked hard and are both proud of our final product. Although it was disappointing when we had to remove our extra features, we were happy (and relieved) to see the robot function as intended. Our completed project garnered a good amount of attention and the other students seemed thoroughly impressed. Perhaps the most impressive was how well the robot executed turns. This project did prove to be a very educational experience, as we drew on our knowledge from a wide range of subjects.
Creators and creation: Thientu Ho (left, creator), David Shu (right, creator), LightRover (center, creation)
# ( Lessons Learned )
Consider everything. We did not expect to have so much trouble with the wheels, especially because of the simple design. We kept our original design very realistic, taking our limited knowledge of mechanical details into consideration, and yet we spent a lot of time dealing with wheels and materials. Finally, this project further proved that it is never safe to assume anything, especially when it comes to your circuit. Even when you verified that it worked ten minutes earlier. Mischevious circuit gnomes have a way of disconnecting wires while your head is turned away.
# ( Safety )
The robot itself is not harmful because it will not move at a very fast speed. However, the CDS-T08 photocell sensors use Cadmium Sulfide (CDS) which is reported to be flammable and a known carcinogen. It is important to keep the sensors away from open flames and food. It is also extremely important not to touch the sensors, but if skin contact occurs to wash hands throughly with soap and water. CDS is also known to have effects on the kidney, lung, and bone. Contact a physician if necessary.
# ( Ethical Considerations )
  1. to accept responsibility in making engineering decisions consistent with the safety, health and welfare of the public, and to disclose promptly factors that might endanger the public or the environment;
    • We spent some time thinking if there were any possible dangers possible. We warned people about the potential hazards of the CDS sensor, and that warning is also in writing on this web page.
  2. to seek, accept, and offer honest criticism of technical work, to acknowledge and correct errors, and to credit properly the contributions of others;
    • We often sought out the help of the course staff and appreciated their insight. We also appreciated the comments from bystanders watching us test LightRover in the lab.
  3. to avoid injuring others, their property, reputation, or employment by false or malicious action;
    • LightRover does not move fast enough to damage anything, and we were very respectful of other people's property and projects.
  4. to improve the understanding of technology, its appropriate application, and potential consequences;
    • The purpose of this project was to learn about sensors, motors, and design. It was very hands on and we learned more than just the technical details.
  5. to assist colleagues and co-workers in their professional development and to support them in following this code of ethics.
    • We tried to be as accomodating as possible to the other groups. For example, another group happened to use the same bipolar stepper motor as the ones we used and asked us how we were able to get it to work. We answered their questions to the best of our ability.
# ( Other Considerations )
As far as we know, the LightRover project does not infringe on any patents. We wrote all our own code and it is now public domain. We do not intend on profiting from this project, it was for educational purposes only.
# ( Thanks )
Thanks to the entire 476 staff for all their help and for keeping the lab open.

4/22/2005 - Cornell University ECE 476 Final Design Project "LightRover"
Thientu Ho
David Shu