Handheld Ultrasonic Rangefinder



Overall, we are quite happy with the results of our rangefinder. This is the one of the first classes weve taken at Cornell that allowed us to build something from scratch that we can actually take home and have pride in accomplishing. Of course, only having a month to do the entire thing means there are some improvements that still can be done.

First off is the LCD. We were quite disappointed that the backlit LCD we had originally purchased did not work. We plan on purchasing the other LCD that was recommended to us so we can have a backlight that works. Being able to use the rangefinder in the dark adds a whole new dimension to its usability. A new pushbutton would also have to be implemented so the user can turn on and off the backlight at his or her convenience.

Mounting the rangefinder in some type of project box or enclosure is another improvement that wed do had we the time. This would make the rangefinder seem more like a finished product that could be marketable. Itd also make using it simpler and single handed.

Lastly, some of the wiring could be improved. As mentioned earlier, the wiring for the receiving and transmitting transducers is very close to each other and causes some interference. The solder board was laid out left to right without any forethought of where certain circuits should be placed in order to reduce noise. Had the receiving circuit been on one side of the board with the transmitting circuit on the other side, our noise and interference issues would most likely have been greatly reduced.

Standards and intellectual property

As mentioned earlier, our rangefinder was built from the ground up and does not interact with any other device. Thus, there were no considerations for standards or intellectual property that were made during its design and construction.

Ethical considerations (based on the IEEE Code of Ethics)

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

When originally coming up with the idea of the rangefinder, we considered possible applications that might be beneficial to the public, yet safe for use. We also are aware of the fact that depending on input voltage, the LM340 voltage regulator may possibly burn the user. Providing means necessary to circumvent the risk by packaging the device in some sort of enclosure would prevent any harm to the user.

3) to be honest and realistic in stating claims or estimates based on available data

When programming the MCU, we had decided to make the rangefinder accurate to the millimeter. Testing proves that this is true. We had also initially intended the rangefinder to work at large distances (a few meters), but due to a hardware wiring issue noise and interference prevented this. This was acknowledged earlier and stated to the user.

7) to seek, accept, and offer honest criticism of technical work, to acknowledge and correct errors, and to credit properly the contributions of others

When we had run into difficulties in the hardware and software design of the rangefinder, we sought help from Prof. Land and some of the many course TAs. They offered assistance which was taken into consideration and is very appreciative. Without their more advanced knowledge in MCUs, programming, and circuit theory, our rangefinder would have never been a success.

8) to treat fairly all persons regardless of such factors as race, religion, gender, disability, age, or national origin

There is no possible way that a single device can treat fairly every single person of every walk of life. Inherent in any device are limitations that will rule out usage by at least one group of people. Our rangefinder can be used by any person who is able push a button and read an LCD display in English using West Arabic (European) numerals. This encompasses the large majority of people on this planet. To accommodate those who cannot see, an audible alarm that emits a periodic tone proportional the measured distance could be implemented.

9) to avoid injuring others, their property, reputation, or employment by false or malicious action

The only output that our rangefinder creates is a short burst of sound at 40 kHz. This is far beyond the range of human hearing, so our device is not capable of harming others. The sound level is also not of significant power to destroy property through shockwaves.