ECE 477Digital Systems Senior Design ProjectSpring 2009

Homework 12: Ethical and Environmental Impact Analysis

Due: Friday, April 17, at NOON

Team Code Name: ______das Autotünr______Group No. __4___

Team Member Completing This Homework: _____David Sutherland______

E-mail Address of Team Member: dsutherl @ purdue.edu

Evaluation:

SCORE

/

DESCRIPTION

10 /

Excellent – among the best papers submitted for this assignment. Very few corrections needed for version submitted in Final Report.

9 /

Very good – all requirements aptly met. Minor additions/corrections needed for version submitted in Final Report.

8 /

Good – all requirements considered and addressed. Several noteworthy additions/corrections needed for version submitted in Final Report.

7 /

Average – all requirements basically met, but some revisions in content should be made for the version submitted in the Final Report.

6 /

Marginal – all requirements met at a nominal level. Significant revisions in content should be made for the version submitted in the Final Report.

* /

Below the passing threshold – major revisions required to meet report requirements at a nominal level. Revise and resubmit.

* Resubmissions are due within one week of the date of return, and will be awarded a score of “6” provided all report requirements have been met at a nominal level.

Comments:

What you covered it good, but I think you have some cases you did not cover in the ethical section. No where did you detail that the end user is not supposed to take the box apart. You probably want to include this in your ethical section. You could place a “warrenty void” sticker over it. Also, the motors have exposed wires and an exposed pad-out circuit. What type of ethical considerations does this have if you would go in production? You should look into putting this into your final report.

1.0Introduction

das Autotünr is a six-string concurrent guitar tuner with the capability to record and save MIDI files to a USB mass storage device. As is with any commercial product, ethical and environmental concerns are paramount to its inception. Since our product will be utilized by interfacing it with the user’s own unique guitar, special care must be taken when testing the possible ways individual guitars can vary to ensure correct, reliable and safe operation. In addition, many failsafes have been built into the design with the intent to lessen the probability of device failure. With regards to environmental impact, thought must be put into how to minimize the inclusion of toxic substances in das Autotünr’s design. Also, the user should be informed of how to properly dispose of the device at the end of its lifetime.

2.0Ethical Impact Analysis

When considering the ethical impact of das Autotünr, it is important to first look at how the device will be used. The device will be attached to the headstock of a user’s guitar with one motor firmly attached to each tuning peg, totaling six motors. In order to ensure the tuning assembly does not slip off the guitar, it will be secured by tightening wing nuts on the underside of the motor brackets. Since removing the motors in case of a failure is not feasible, if the device becomes unresponsive and the motors are stuck rotating, there must be a failsafe to ensure that harm does not come to the guitar or the user[KH1]. If the failsafe were[KH2] not engaged, and if all other designed safety mechanisms failed[KH3], the most likely scenarios would involve breaking a guitar string, resulting in injury to the user or causing permanent damage to the guitar itself. Since user safety is paramount, the safety mechanisms and failsafes must be designed in such a way that the probability this situation occurs is negligible.

The design includes many different routines to ensure the correct, safe and reliable operation of the tuner. During normal operation, das Autotünr should tune all six strings concurrently, but in the case of any discrepancy in the frequency detection or perceived motor operation, the device will enter what is called “single string” tuning mode. The screen will instruct the user to play one string at a time, starting with the lowest string. This way, the device can more reliably detect the frequency of the string and motor control can further be verified. If the frequency of the string does not change when the motor is set to rotate, the device will exit tuning mode and the user will be prompted to check the motor connections. In addition, if any of the string frequencies indicate the guitar is being tuned beyond safe string tension levels, the tuning routine will exit. Also, at any time during the tuning process, if the user feels that the device is operating unsafely or that they want to halt the tuning process, they can press a button on the control box which will stop all motor operation. Given all of these safety mechanisms, the design of dasAutotünr is certainly conscious of failures, but extensive testing must follow to make certain the device’s proper functioning under a variety of conditions.[KH4]

To this end, it is important to analyze and test the set of variables involved its intended operation. If dasAutotünr were to go into production, it might be assumed that it would tune any guitar, but further testing would need to be performed to verify the breadth of its capabilities. This testing would involve confirming the tuning capabilities of the device when used with different guitar types (acoustic and electric), string materials, string gauges and pickups (in the case of an electric guitar). If it was found that performance was sub-par or that it would be dangerous to use dasAutotünr given any combination of these variables, further investigation of the failure would be needed. If the device design could be easily, quickly and unobtrusively modified, it would be a reasonable course of action to go forward with simple changes to increase the likelihood of operational success. If the changes would be too drastic, difficult or impossible given the present design, this incompatibility would have to be printed on the packaging, to prevent the purchase of a product for which the consumer would have no use. During the course of testing, if it was shown that the number of cases where dasAutotünr failed to perform its function was unacceptably high, or if any test case resulted in high likelihood of injury to the user, the design would require significant modifications before it would be ready for commercial sale.[KH5]

When the device passed all testing of its intended functionality, documentation must clearly provide directions for safe operation of dasAutotünr. Additionally, it should be documented which instruments das Autotünr is not intended to be used to tune. This device was intended to be an electric or acoustic guitar tuner and its performance will not be validated on other similar string instruments. There should also be a warning in the manual stating that there is a risk of string breakage resulting in personal injury and which steps should be taken to lessen these risks.[KH6]

3.0Environmental Impact Analysis

In order to present an ethically-sound product, the environmental impact of the device’s manufacture and disposal must be thoroughly considered. The foundation of an environmentally-friendly product begins with how it is manufactured and which parts go into its production. One of the greatest health hazards present in most electronic devices is lead,and if ingested in sufficient quantities, can cause neurological damage, hearing loss or even cancer [1]. It is commonly found in solder and is frequently used to create the traces on a printed circuit board. Fortunately, there are alternatives which eliminate the use for leaded products. Lead-free solder is frequently used by manufacturers looking to eliminate their environmental impact. For this reason, it is seen as positive, but it has not been adopted as an industry-standard due to its relatively-inferior performance. This shortcoming is especially evident with regard to solder joint reliability, a common failure mode for electronic devices [2]. Furthermore, both lead-free solder and lead-free PCBs come at a price premium as compared to their leaded counterparts [3]. In addition to manufacturing the PCB using lead-free processes, RoHS approved ICs can be employed. Devices carrying this label must have less than 0.1% by weight of lead, mercury, chromium, PPBs and PBDEs and less than .01% by weight of cadmium [4]. Another upside to using these parts is that they are frequently priced the same as non-RoHS parts. This means that there will be minimal impact to the bottom line, but a net decrease in toxic substances contained in the device.

During normal use of das Autotünr, any direct environmental impacts would be small. One possibility might be that if the LCD on the control box were to be broken, the mercury in the fluorescent backlight could spill out. Another impact might be that the device, when left plugged in, will continue to draw electricity due to the losses in the AC/DC power supply and idle current draw of the circuitry. The user manual should recommend that the unit is unplugged when not in use to reduce unnecessary power consumption.[KH7]

In contrast to the relatively slight impacts of usage, the environmental impact at the end of das Autotünr’s lifetime has the potential to be significant. Proper disposal of the device is key in minimizing both its landfill footprint and its potential to release toxic substances to the environment. Both the Lexan brackets used for the motor mounting and the plastic control box are able to be recycled at most community recycling centers. Both the motors and the PCB can be recycled either at electronics-accepting local recycling centers or at specialized electronic recycling centers [5]. Unfortunately, the availability will vary by location, but the user manual should list a URL to the EPA site which provides a search for recycling centers by city. This should increase the likelihood that the end-user will actually recycle the device, rather than putting it in the trashcan.

4.0Summary

Special care should be taken when implementing any product to adhere to ethical principlesand to ensure a user-friendly and environmentally-sound result. Throughout the design of das Autotünr, special care has been taken to reduce the possibility of a situation involving personal injury or inadvertent property damage. Additionally, environmentally-friendly practices and principles have been explored and acted upon to reduce the impact das Autotünr will have throughout its lifetime. All of this work should result in a product that realizes ethical and environmentally-minded design practices.
List of References

[1]Agency for Toxic Substances & Disease Registry, “ATSDR – ToxFAWs: Lead,” August 2007.Accessed: April 16, 2009.

[2]Vandevelde, Gonzalez, Limaye, et al., “Lead Free Solder Join Reliability Estimation by Finite Element Modelling Advantages, Challenges and Limitations,” IMEC, 2004.

[3]Advanced Circuits, “Printed Circuit Boards Instant Quote Online,” Accessed: April 16, 2009.

[4]RoHS Compliance, “RoHS Compliance in the EU.” Accessed: April 16, 2009.

[5]Environmental Protection Agency, “Basic Information | eCycling | US EPA.” Accessed: April 16, 2009.

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[KH1]Wording, fix this sentence it does not flow correctly.

[KH2]“is”

[KH3]“have failed”

[KH4]Good discussion here.

[KH5]What about using function generators to test it?

[KH6]You should probably also document that the device is not a novelty device or a toy.

[KH7]Good