- 20-20 Hindsight
We began this project with the goal of using the accelerometers to create an inertial position tracking device. We developed the mathematical theory, hardware, and software for 2D positioning only to discover that we could not get the accuracy we needed out of the hardware. The drift on the accelerometers was too great and the device drifted noticeably within a very short period of time, even when left stationary. This was both very dissapointing and very disheartening, but we persevered and managed to salvage some of the hardware and software work for use in Digi-Lev. We are very satisfied with our accomplishment in Digi-Lev but can't shake the feeling incompleteness with the positioning device non-functional. Although we felt and still feel that the positioning device is practically possible, we learned a hard lesson about noise reduction and accuracy from electronics. Perhaps given a second shot we would use surface mount components that would lie close to the accelerometer and order high accuracy op-amps in an effort to ramp the accelerometer output.
- Intellectual Property
The Digi-Lev design is entirely original and not based on or reverse engineered from any existing design. The software too is proprietary to the developers with the exception of the ADC interrupt service routine and the read_adc() function which were generated by the CodeVision AVR C compiler Project Wizard. The dual axis accelerometers were sampled from Analog Devices without stipulation of non-disclosure.
- Ethical Considerations
"to improve the understanding of technology, its appropriate application, and potential consequences"
By the creation of this website and documentation of our work on Digi-Lev we hope to improve the understanding of the technology we used an developed in an effort to help those who will encounter it in the future.
"to maintain and improve our technical competence and to undertake technological tasks for others only if qualified by training or experience, or after full disclosure of pertinent limitations"
Upon approaching graduation from the School of Engineering at Cornell we felt we were qualified to undertake this project and have seen it through to completion. In the process, we have learned much in the way of designing and developing embedded devices while maintaining through reuse the knowledge we've gained in our engineering coursework on software development and electronics.
"to be honest and realistic in stating claims or estimates based on available data"
We described our device as accurate to within one degree whereas there is a very good possibility that it can be much more accurate given the careful mathematics of accounting for every bit of accuracy available from the ADC. However, as mentioned, due to a lack of accurate measuring and positioning equipment, we could not honestly back up claims of greater accuracy and so we refrained from boasting a high precision device.
"to seek, accept, and offer honest criticism of technical work, to acknowledge and correct errors, and to credit properly the contributions of others"
Very often we sought help from Prof. Land, the very patient teaching assistants, and other students in the class. We have tried throughout this documentation to give credit where credit is due and would like to thank everyone who contributed to Digi-Lev for their assistance and expertise.
"to assist colleagues and co-workers in their professional development and to support them in following this code of ethics"
Throughout the many hours we spent in the lab, we have always been willing to help anyone with questions or concerns that our experience helps us to address. Frequently we have had the opportunity to help our fellow classmates be it with technical questions about the MCU or other devices we worked with or specific expertise such as creating screen captures of video projects (which we did in Lab 4 and was helpful to those seeking to do the same in their final project).