ECE 477 Digital Systems Senior Design Project Spring 2006

Homework 12: Ethical and Environmental Impact Analysis

Due: Friday, April 14, at NOON

Team Code Name: The Soviet Challenge Group No. 6

Team Member Completing This Homework: Kyle McGhee

E-mail Address of Report Author: kmcghee@ purdue.edu

Evaluation:

Component/Criterion / Score / Multiplier / Points

Introduction and Summary

/ 0 1 2 3 4 5 6 7 8 9 10 / X 1
Ethical Impact Analysis / 0 1 2 3 4 5 6 7 8 9 10 / X 3
Environmental Impact Analysis / 0 1 2 3 4 5 6 7 8 9 10 / X 3
List of References / 0 1 2 3 4 5 6 7 8 9 10 / X 2
Technical Writing Style / 0 1 2 3 4 5 6 7 8 9 10 / X 1
TOTAL

Comments:

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1.0  Introduction

The Soviet Challenge is a handheld, wireless internet enabled, TetriNET client. As its name implies, it is capable of connecting to an existing TetriNET server, and executing an embedded version of the Tetris-like game. Typical of handheld gaming devices, its major components include a graphic LCD module and several simple pushbuttons for input. Standard IEEE 802.11 wireless internet access is implemented via a removable wireless Compact Flash card. The device also contains a polymer lithium-ion rechargeable battery pack, and associated circuitry necessary for recharging and measuring remaining battery power.

The risk of physical injury under proper usage of the device is minute. The alleged dangers of certain components (LCD, pushbuttons, wireless) are well researched and publicly regarded as nonissues. Conversely, the hazards of the polymer lithium-ion battery pack are substantial. Due to remarkable stability in other portions of the design, device reliability is limited primarily by current rechargeable battery technologies.

Mass production of the device would present few environmental issues. No unique or exceptional constraints need be considered for the manufacturing portion of the device life cycle, other than those of any device containing a printed circuit board. Similarly, there need be very little concern during normal use, unless abnormal activity is performed to the battery. Finally, care must be taken when disposing of the printed circuit board and battery.

2.0  Ethical Impact Analysis

The Soviet Challenge finds itself subject to multiple common ethical concerns. These concerns, arisen by frequent and abundant use of the related component, have been thoroughly researched. While they have been deemed trivial (and sometimes even fictitious), they are still worth remark. However, as in virtually all electronic designs, there is some small prospect of injury. Naturally, this chance has been minimized through a rigorous and predictive design methodology. The same technique has been applied to maximize reliability – the least reliable component has a mean time to failure of seven years. The polymer lithium-ion battery pack therefore restricts the total product lifetime to its own cycle limit.

2.1  Safety Considerations

Many graphic LCD modules – primarily those utilizing CCFL backlights – require considerable voltage levels, approaching a kilovolt. Consequently, the Soviet Challenge makes use of an LED backlit graphic LCD module, and requires little more than a few volts. Concern of the device causing epileptic seizures is implausible. Photosensitive epileptics are generally susceptible to flicker between 16 and 25 Hz, whereas the LCD module employed is flicker-free (the backlight is always enabled). Risk of provoked seizure may be increased by high contrast patterns, due to sharpness of the image [1]. This risk, although unlikely, can be legally avoided with a warning label shipped with the final package.

While it can be easily avoided, soreness in the hands, arms, or eyes can result from excessive, unbroken play. Permanent repetitive motion injury such as carpal tunnel syndrome or tendonitis due to excessive, unbroken play is unlikely. Such injuries are more likely to occur from “congenital predisposition” [2]. There have been past instances of repetitive motion injury due to electronic devices, but these were principally large, forceful, vibrating power-tools (such as jack hammers). Again, this risk, although unlikely, can be legally avoided with yet another warning label.

Although more controversial, the issue of hazard of radiation due to standard IEEE 802.11 wireless radio frequencies is unfounded. There is no evidence that devices that use these technologies pose a danger to users or the public [3, 4]. However, as with all wireless devices, radio waves emitted from the Soviet Challenge can affect the operation of nearby electronics, including cardiac pacemakers. Another warning label must be packaged with the device stressing the importance of selective location-based operation, and avoidance of use near medical or flight-related equipment.

Leakage of ingredients contained within the polymer lithium-ion battery pack can cause personal injury as well as damage to the Soviet Challenge device. Simultaneously, these ingredients will react violently in contact with water. The batteries are well protected inside the device packaging, but additional care should be taken during operation. Rapid charge or discharge, as well as overcharging can also cause the battery pack to react violently. A protection circuit intended to isolate the battery in such cases is currently employed. Finally, several of the components involved in the power circuitry approach dangerous temperatures (in particular, the FZT749 PNP low saturation transistor). However, these are safely located inside the package.

2.2  Reliability Considerations

As it would be unethical to manufacture an unsafe product, it would be equally unethical to manufacture an unreliable one. Due predominantly to few moving components, the Soviet Challenge as an electronic device has a very high mean time to failure, at roughly seven years [5]. The implication of this anomaly is that the device is more likely to effectively wear out than it is to randomly fail, due to a finite number of charge cycles in the polymer lithium-ion battery pack. This occurs not from design flaw, but from limitations in current rechargeable battery technology. This regrettable quality can be managed by offering replacement battery installation services, after production.

3.0  Environmental Impact Analysis

Very little atypical consideration needs to be taken with regards to the environmental impact of the Soviet Challenge through all three stages of the product’s life cycle. Concern necessary for the manufacturing stage is identical to that of any other simple device containing a printed circuit board. During normal use, some care must be taken with regards to the polymer lithium-ion battery; however the care can be considered avoidance of abnormal use. Finally, the consumer should be coerced to properly dispose of the device, as attention should be given to the disposal of both the battery and the printed circuit board.

3.1  Manufacturing

The Soviet Challenge makes use of many components, however only the printed circuit board (PCB) is produced internally while the other components are purchased from other manufacturers and vendors. For this reason, only the manufacturing process of the PCB must be considered.

Production of a PCB is a long process involving many different procedures that utilize toxic chemicals, and generate dangerous byproducts. The waste generated can be attributed to five distinctive techniques of the manufacturing process [6, 7]. The state of California enumerates these stages, and presents possible improvements. The first of these is termed Cleaning and Surface Preparation, wherein a non-conductive substrate is readied. Among other things, acids, halogenated solvents, and alkali are generated as waste. These undesired chemicals could be reduced significantly by using a different, non-chelated cleaner, or simply recycling and reusing existing cleaning solution [7].

The second waste-generating procedure is Catalyst Application and Electroless Plating. Wastes produced by this technique include acids, stannic oxide, palladium, and additional chelating agents. If non-cyanide baths were used, waste streams were segregated, metal values were recovered, or bath life were extended, less aggregate waste would be created [7]. The third process is Pattern Printing and Masking, in which areas of copper foil are chemically marked to remain after etching. Vinyl polymers, chlorinated hydrocarbons, various organic solvents, and alkali are generated at this point. A method to reduce waste production in this process would be to use some method of dry photoresist removal, or to simply reuse the existing photoresist stripper [7].

The fourth waste-producing process of PCB manufacturing is termed Electroplating. In this procedure many metals including copper, nickel, tin (or lead), and gold are discarded, as well as fluoride, cyanide, and sulfate. These wastes could be reduced again by extending bath life, segregating waste streams, or recovering metal values [7]. The fifth and final waste-generating process of PCB manufacturing is termed Etching, and is the method by which superfluous copper is removed. In this process ammonia, chromium, copper, iron, and various acids are produced. Finally, it could be environmentally improved by recycling etchants, using non-chelated etchant, or by using electrolytic recovery, a purifying technique that extracts metal ions [8]. Note that these processes need not be employed; they would merely minimize the environmental impact of manufacturing the device by minimizing waste output.

3.2  Normal Use

Normal use of the Soviet Challenge handheld gaming device proves to cause few environmental concerns. The radiofrequency radiation due to 802.11 wireless internet is currently considered harmless. The radiation emitting portion of the device (the wireless Compact Flash card) is removable, and internet access is already focused into “hot-spots” about a wireless router, so if action need be taken, the dilemma would be easily resolved.

The polymer lithium-ion rechargeable battery will function correctly under normal use. This usage excludes placing the battery in fire or near a heat source; submerging in water, seawater, or allowing to get wet; piercing or applying a large force; throwing; reversing the positive and negative terminals; shorting the terminals; connecting to an electrical outlet, vehicle cigarette lighter, or otherwise exposing to large current; or attempting to disassemble, repair or deform [9]. The battery contains a lithium salt electrolyte held in a solid polymer composite [10]. This polymer, for instance polyacrylonitrile, is not flammable, however may produce hydrogen cyanide under heat, and is therefore highly toxic, depending on the exact polymer used. The lithium in the polymer will also react violently with water. Regardless, under normal use the contents of the battery should never escape the packaging, and extensive measures have already been taken to assure this, including multiple levels of packaging around the batteries.

3.3  Disposal & Recycling

As could be inferred from the environmental considerations of manufacturing and normal use, the two components of the Soviet Challenge that require special care in disposal are the PCB and the polymer lithium-ion battery pack. The LCD has an attached PCB, so care must be taken in its disposal as well. The remaining components of the device can be treated as ordinary trash, or recycled as they are primarily plastic. Depending on the manufacturing process, the PCB likely contains hazardous materials, such as lead. If submitted to some organizations, recovery of many of the original chemicals used to create the PCB may be possible, including precious metals [11]. A similar process can be applied to the polymer lithium-ion batteries, and much of the original lithium and polymer can be harvested and used again [12].

4.0  Summary

Environmental considerations for the Soviet Challenge are nothing out of the ordinary, and revolve around the printed circuit board (PCB) and polymer lithium-ion battery. Disposal of the battery and PCB requires special thought as both could contain toxic chemicals. Normal use of the device should not present any environmental issues, so long as the battery is not perturbed. Manufacturing of the PCB need only consider typical environmental concerns, as all other components must be purchased from other manufacturers and vendors.

Ethical considerations have been made in the design of the device as well. The Soviet Challenge has been devised to be as reliable as possible, and indeed its life cycle is limited by current technology. Many safety popular issues have been considered and deemed minuscule, with the exception of the volatility of the polymer lithium-ion rechargeable battery pack employed by the system. However, sufficient protection is already currently in place.


List of References

[1]  “Epilepsy Action: Photosensitive Epilepsy" [Online Document], Available HTTP:
http://www.epilepsy.org.uk/info/photo_computers.html

[2]  “Carpal Tunnel Syndrome Fact Sheet: National Institute of Neurological Disorders and Stroke (NINDS)” [Online Document], Available HTTP:
http://www.ninds.nih.gov/disorders/carpal_tunnel/detail_carpal_tunnel.htm#51823049

[3]  “Motorola RFHealth” [Online Document], Available HTTP:
http://www.motorola.com/content/0,,2376,00.html

[4]  “Recent Advances in Research on Radiofrequency Fields and Health: 2001-2003” [Online Document], Available HTTP:
http://www.rsc.ca//files/publications/expert_panels/RF//expert_panel_radiofrequency_update2.pdf

[5]  “ECE 477, Spring ’06, Team 6 – Homework 11: Reliability and Safety Analysis”, Allan Patterson [Online Document], Available HTTP:
http://shay.ecn.purdue.edu/~477grp6/hw11.doc

[6]  “Printed Circuit Board Manufacturing” [Online Document], Available HTTP:
http://www.inece.org/mmcourse/chapt7.pdf

[7]  “Pollution Prevention for Printed Circuit Board Manufacturing 3672” [Online Document], Available HTTP:
http://www.calgold.ca.gov/P2/3672.htm

[8]  “Fact Sheet: Metal Recovery Technologies for the Metal Finishing Industry” [Online Document], Available HTTP:
http://es.epa.gov/techinfo/facts/michigan/michfs20.html

[9]  “Polymer Lithium-Ion Battery Safety and Handling” [Online Document], Available HTTP:
http://www.advantagecircuits.com/ProductDatasheet/BatterySafety.pdf

[10]  “Lithium Ion Polymer Battery” [Online Document], Available HTTP:
http://en.wikipedia.org/wiki/Lithium_polymer_cell

[11]  “Printed Circuit Board Recycling” [Online Document], Available HTTP:
http://p2library.nfesc.navy.mil/P2_Opportunity_Handbook/2_II_8.html

[12]  “Battery Recycling Information Sheet” [Online Document], Available HTTP:
http://www.wasteonline.org.uk/resources/InformationSheets/Batteries.htm

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