Hand crank radio
From DDL Wiki
The hand crank, solar radio shown above was analyzed to determine its components, functionality, assembly techniques and design strengths and weaknesses. To accomplish that, we dissected the product to gain a better understanding of the components and their mechanical (or non-mechanical) functions within the system. Some of the main parts of the emergency-radio include a generator, a gear box, a hand crank, a solar panel and a series of electronic circuits. These parts are mainly used to transfer the energy into sound and into different functions that come available with the radio. Some of these functions are the On/Off/Volume dial, the tuner dial and the antenna.
After the product dissection, we performed three different analyses on the device: Failure Modes and Effects Analysis (FMEA), Design for Manufacture and Assembly (DFMA) and Design for Environment (DFE). The purpose of FMEA was to gain a better understanding of the possible failure modes that may occur when the user interacts with the radio, and what effects these failures could have on the user and its surroundings. From our analysis, it was clear that most of the possible failure modes will not have a harmful effect on the user but may render the system inoperable.
The DFMA gave us a better insight of how each part was manufactured and assembled, what materials were used, and whether the manufacturing techniques were effective when assembling each part. There are some features that the manufacturer made to ease the process of assembly but there is still room for improvements.
The DFE analysis provided insight into the product’s impact on the environment. Results from a similar approach EIO-LCA (Economic Input Output-Life Cycle Analysis) delineated how the existence of the hand crank radio impacts the greenhouse gas emissions of various sectors of the economy. Since this device is self-contained (i.e. generates its own power), power generation and supply during manufacturing contributes the most to GHG emissions. To reduce the amount of pollution caused by the production, use, and disposal, several options are presented in the corresponding section below.
Stakeholders and Product Needs
There are four main stakeholders concerned with this product: consumers, distributors / retailers, manufacturers and transporters (shipment). Each of the stakeholders have different needs as listed below.
The Kikkerland Solar Radio Crank is directed toward household consumers who are concerned about their carbon footprint or natural disasters (which may cause extended power outages). Based on our user studies, these are some areas that consumers feel the radio can be improved on.
- Cheaper product price
- Clarity & loudness of radio
- Durability & reliability
- Efficiency of solar cell & crank (i.e. number of rotations to minutes of radio time)
- Ease of use
- Ease of tuning
- Better signal reception
- Fast shipping and efficient transport
Distributors / Retailers
For retailers and distributors, the following characteristics of the radio may come in handy.
- Efficient packaging for cheap & easy transport
- Safe packaging to protect the product functions
- Appealing packaging to display at the store
- Minimal waste packaging
- Product must be in demand
- Ease of storage (e.g. stackability)
- High demand
The Kikkerland Solar Radio Crank should meet the demands of the customer while being produced at minimum expense, and hence earning the company a better profit margin. Below are some aspects that the manufactures want in their production of the radio.
- Less parts
- Common materials
- Easy assembly to reduce labor costs
- Automated assembly
- Standardized parts
- Reduce shipping costs
- Cheaper production costs
- High demand
Shipping / Transport
For ease of transports, these characteristics are important.
- Ease of storage (e.g. stackability)
- High demand (e.g. large shipment quantities)
How It is Used
This radio requires neither a battery nor a power cord to function. For power, this radio possesses a small solar panel on its upper face as well as a hand crank on its side as shown in the figures below.
The solar panel allows the user to leave the radio exposed to direct sunlight and listen to their favorite station while the radio gathers solar energy. The hand crank is especially useful indoors, during nighttime, or in emergency situations where light is not directly accessible. The radio contains a dynamo generator that can store the energy created by manual-cranking and gathered from the solar panel in the 300 mAh/2.3 Ni-MH battery. Here are the steps to operate the dynamo solar radio:
- Rotate arm or expose radio to sun to generate energy
- 1 min cranking = 30 min radio play time
- 5 hours sunlight = 30 min radio play time
- Turn the On/Off/Volume dial
- Change frequencies by switching the AM/FM/WB switch
- Turn tuning dial to change stations
- Plug in headphones for headphone option
Radio Frequency Available:
- Fm Frequency Range: 87-108 MHz
- Am Frequency Range: 530-1600 kHz
- Radio Frequency Range: 149-186 MHz
The portable hand-cranked radio seemed very easy to use. However, there were a few areas of design that must be changed. For instance, the resistance of the crank motion seems to be proportional to the speed of the cranking. The faster the cranking is, the more power is generated but the bigger the resistance becomes. There is a need to be able to find a balance point between resistance in the wheels and power generated from the crank and the solar panel.
While researching this product, there were a few common themes in the review of the product. They are as follow:
- Direct sunlight is needed for the panels to absorb sunlight efficiently
- Antenna for the radio goes straight up, it does not bend
- If you are using the product outside in a sunny day, you never have to crank for power as the solar panel itself will provide the radio with enough power
- On average, 1 minute of cranking gives approximately 15-25 minutes of playing time. Or, 100 turns of the crank is equal to approximate 10 minutes of audio
- The radio is small and light, it fits in the palm of your hand
From these comments, it can be concluded that the energy conversion either from mechanical to electrical, or from solar to electrical, is quite efficient. With a few tweaks, it may be possible to integrate this system with other daily life appliances to convert the rolling mechanical energy into electrical energy. A cheap and portable system to recapture the energy lost from a mechanical process in our daily life may present an interesting research and business opportunity. To achieve these goals for the design process, additional understanding and research on the product must be done.
Bill of Materials
This hand crank radio has 41 components in total. Other than the electronics, most of the components are made out of plastics through injection molding or stamping. A ruler is included in all of the pictures to provide a sense of scale. Please refer to figure 6 under the assembly table to see all of the components.
|Part Number||Name||QTY||Weight (g)||Function||Material||Manufacturing Process||Image|
|1||Back Case||1||31.2||Holding the assembly together. Where the crank is attached||Plastic||Injection molding|
|2||Speaker Screen Mesh||1||8.5||Protecting the speaker from physical disturbance||Steel||Stamping|
|3||Front Case||1||25.5||Holding the speaker||Plastic||Injection molding|
|4||Speaker Plate||1||8.5||Housing the magnet to create the vibration||Steel||Stamping|
|5||Speaker Cone||1||Less than a gram||Vibrating to produce the sound||Plastic / Polymer||Stamping, Vacuum forming|
|6||Solar Panel Assembly||1||5.7||Converting solar energy to electrical energy||Monocrystalline Silicon Wafer, Plastic, Lead, Rubber, Copper||Soldering, Lithography, Masking, Depositing, Etching|
|7||Radio Station Tuner Indicator||1||Less than a gram||Indicating the frequency of the radio||Plastic||Injection molding, Printing for labels|
|8||Generator Magnet||1||2.8||Producing magnetic field to generate electricity||Metal Alloys||Pressing, Heating, Annealing, Finishing, Magnetizing|
|9||Generator Plate||1||14.2||Holding gears and generator in place||Steel||Stamping|
|10||Gear 4||1||Less than a gram||Connecting the generator to other gears||Steel||Hobbing|
|11||Gear Shaft||1||Less than a gram||Connecting the generator to gear 4, Mounting gear 4||Steel||Cold rolling|
|12||Gear 1||1||Less than a gram||Translating crank motion||Nylon (self-lubricating)||Injection molding|
|13||Generator||1||11.3||Generating electricity from rotation||Copper, Steel||Stamping, Layering, Coiling|
|14||Gear 2||1||Less than a gram||Translating crank motion||Nylon (self-lubricating)||Injection molding|
|15||Generator Shell||1||5.7||Holding the magnet in place||Steel||Stamping|
|16||Gear 3||1||Less than a gram||Translating crank motion||Nylon (self-lubricating)||Injection molding|
|17||Battery Pack||1||14.2||Storing energy for radio operation||Plastic, Copper, Rubber, Nickel Metal Hydride||Advanced manufacturing technique|
|18||Volume and Power Circuit Assembly||1||8.5||Control the volume and turn on the radio||Plastic, Lead, Copper, Rubber, Semi Conducting Materials, Polymer / Wax||Soldering, Lithography, Masking, Depositing, Etching|
|19||Outside Screw||4||Less than a gram||Hold the two cases together||Stainless Steel||Cold heading, Thread rolling|
|20||Speaker Screw||3||Less than a gram||Attaching the speaker to the front case||Stainless Steel||Cold heading, Thread rolling|
|21||Antenna's Solenoid||1||Less than a gram||Generating the magnetic field required for radio signal||Copper||Coiling, Hardening|
|22||Solar Panel Pad||2||Less than a gram||Stabilize the solar panel||Foam / Paper / Polymer||Polymerization forming|
|23||Crank Dowel||1||Less than a gram||Connecting crank shaft and collar||Steel||Cold rolling|
|24||On / Off / Volume Indicator||1||Less than a gram||Adjust speaker volume||Plastic||Injection molding, Printing for labels|
|25||Antenna||1||8.5||Enhancing signal reception||Stainless steel, Aluminum, Brass||Cold drawing, Die drawing|
|26||Headphone Jack Assembly||1||Less than a gram||Connecting headphone to the speaker||Copper, Plastic, Rubber, Steel, Lead||Soldering, Lithography, Masking, Depositing, Etching|
|27||Crank Knob||1||2.8||Making it easier to turn the crank||Plastic||Injection molding|
|28||Crank Shaft||1||2.8||Increasing the lever arm||Plastic||Injection Molding|
|29||Crank's Attachment Disk||1||2.8||Connecting crank shaft to the gear||Plastic||Injection Molding|
|30||Hand crank collar||1||Less than a gram||Stabilizing the rotational movement of the crank||Steel||Stamping|
|31||Tuning Microprocessor Assembly||1||22.7||Tuning the radio frequency (FM / AM / WB)||Plastic, Lead, Copper, Rubber, Semi Conducting Materials, Polymer / Wax||Soldering, Lithography, Masking, Depositing, Etching|
|32||Generator screws||4 (3 different kinds)||Less than a gram||Holding generator to the case and the gear system||Stainless Steel||Cold heading, Thread rolling|
|33||Headphone Screws||2||Less than a gram||Holding headphone adapter||Stainless Steel||Cold heading, Thread rolling|
|34||Antenna Screw||1||Less than a gram||Holding the antenna to the case||Stainless Steel||Cold heading, Thread rolling|
|35||Crank-Gear Collar||1||Less than a gram||Connecting the crank's collar and the gear||Plastic||Injection molding|
|36||Gear Collar Clamps||2||Less than a gram||Holding the gears together||Steel||Stamping|
|37||Frequency Range Switch Knob||1||Less than a gram||Indicating if the frequency range of the radio (FM / AM / WB)||Plastic||Injection molding|
|38||Cable||1||Less than a gram||Connecting electrical components||Copper, Rubber||Drawing through rubber die|
|39||O Ring||2||Less than a gram||Mounting the magnet on top of the generator||Plastic||Stamping|
|40||Speaker Magnet||1||2.8||Controlling the vibration of the speaker to generate the sound||Metal alloys||Pressing, Heating, Annealing, Finishing, Magnetizing|
|41||Speaker Coil||1||8.5||Allowing the speaker screen to vibrate||Copper||Rolling|
The parts cannot be assembled back after taking them apart due to the wire connections that need to be severed to separate the integrated circuits. The assembly procedure can, however, be described as follows:
- Assemble the gear box with the generator by attaching it to part 9. (Gear box consists of part 10, 12, 14, 15, 16, 36 and Generator consists of part 8, 11, 13, 15, 39).
- Assemble the speaker by putting the magnet (part 40) on the speaker plate (part 4) and then attach the speaker coil (part 41) to the speaker cone (part 5). Attach the two assemblies together.
- Connect the integrated circuits together using the cables with their corresponding indicator (part 6, 7, 17, 18, 24, 26, 31, 37, 38).
- Connect the antenna and the solenoid with the integrated circuit (part 21, 25, 31, 34, 38).
- Assemble the hand crank (part 23, 27, 28, 29, 30, 35).
- Insert hand crank assembly to the back case (part 1).
- Connect the generator and gear assembly to the back case (using part 32).
- Connect the speaker assembly to the front case (part 3 using part 20).
- Attach the integrated circuits to the front case and fasten the headphone jack using part 33, attach the solar panel using pads (part 22).
- Attach the front case to the back case using part 19.
- Lastly insert the speaker screen mesh (part 2) to the front case.
The mechanical aspect is comprised of the generator-crank system. The basic structure is as follows (please refer to figure 6 for reference):
The hand crank contains a handle that’s rigidly attached to a shaft, which is then mounted to gear 1. The purpose of the handle is to make it easier for the user to “crank” and thereby input torque into the gear system to be amplified. The gear system composes of 4 gears, with gear 1 being the input torque gear, gear 4 being the output torque gear, and gears 2 and 4 being the angular velocity magnification gears. Moreover, gear 4 is connected to a shaft that rotates the generator shell. The idea behind the gear system is that with one full “crank” of the handle, the gears will magnify this one rotation into 10 or 20 full rotations of gear 4. This drastically increases efficiency in rotating the generator shell to generate electricity. According to Faraday’s Law of Induction, the rotation of the generator shell generates a magnetic field, which then generates a current that can be stored and used by the hand crank radio.
The faster the rotation, the more current that is generated; therefore, the gear system is designed to have a higher power and lower speed input from the user that is to be converted into a lower power, but higher speed into the generator. Therefore, when the user wishes to play the ratio, he must manually turn the crank in order to generate the magnetic field that would in turn generate electric current which powers the hand crank radio.
Design for Manufacturing and Assembly (DFMA)
The main objective of Design for Manufacturing and Assembly (DFMA) analysis is to come up with various improvements geared towards simplifying the manufacturing and assembly process. Some important considerations may include part count, material selection, production volume, tolerances, etc.
This hand crank radio consists of 41 parts and assemblies as shown in the section above. The majority of the non-metal parts are made out of plastic or rubber through injection molding or stamping. These are pretty efficient methods of manufacturing non-metal components for mass production. The metal components, on the other hand, are made out of various materials including steel, aluminum, metal alloys, and many others. Depending on the use and the shape of the metal components, the manufacturing processes range from cold rolling, stamping, lithography, etc.
Some efforts have been made to simplify the design for the ease of manufacturing and assembly. These methods include:
- Bent tabs on the speaker screen makes it easy to assemble and enables it to be attached without additional parts.
- Most gears are made out of self-lubricating nylon, with standardized size and materials designed to minimize friction.
- Most of the non-metal components are made with injection molding. By changing the mold, a standard injection molding can potentially produce all of the non-metal components.
- The outer case are made with the same dimension allowing them to share similar features and enabling them to be fastened with each other easily.
- A lot of the control knobs are integrated. For instance, the on/off and volume controls are integrated in a single indicator, reducing the part count and simplifying the design.
- Parts with little need of tight tolerances are made out of plastic through injection molding, avoiding the need to scrutinize dimensions during the manufacturing process.
- Most of the non-metal parts are made through injection molding without the need of any secondary manufacturing process.
- Gears are injection molded in the same color for ease of coordination and the outer case is injection molded in green for aesthetic and environmental appeal (i.e. the radio is environmentally friendly, suggested by it's "greeness").
- Threaded holes eliminate the need of nuts and washers, minimizing the part count and ensuring fast assembly.
- Most of the electronics come in sub-assemblies which can be mass produced by other factories, allowing the manufacturer of the radio to specialize in assembling the radio together.
- Although the front case and back case look very similar, they are very easy to differentiate from one another.
- Plastic sockets with different sizes and champfers indicate where to attach which electrical assemblies on the cases.
Some improvements can be made in the following areas:
- There are a lot of screws with various sizes. Standardized screws will make the assembly process simpler and faster.
- The various circuit boards can be combined into one circuit board, minimizing part count and simplifying the assembly.
- The gear assembly seems complicated and difficult to disassemble due to space and volume constraint.
- The metal gear was pressed fit in. This procedure requires high accuracy and low tolerance.
- The wires connect circuit assemblies on both sides of the cases making it difficult to disassemble if there is anything wrong.
- Snap fits can be used instead of screws in some cases.
Failure Modes and Effects Analysis (FMEA)
Failure mode and effects analysis (FMEA) of the Kikkerland Dynamo Solar and Crank Emergency Radio provides great insight into the current application of the dynamo generator and solar panel in a marketable product. This product has shown to be a very compact piece that successfully houses numerous components, allowing for diverse functions. However this radio is not without its faults with various identifiable modes of failure, tabulated below.
Overall the occurrence rating (O) of failure in its various modes is rather low, peaking at 5 for one mode. This indicates that one should expect this product to retain functionality over an extended period of time. Unfortunately, the severity of failures (S) has a maximum rating of 7 for four modes, and a rating of 6 for four modes. Also the detection of failure rating (D) is relatively low with most ratings below 4, but it has one mode with a rating of 9 and another with 8. However, the design rates well overall, indicated by the highest RPN rating of 105.
Therefore, the Kikkerland product has shown to have been designed quite well with a high longevity of use. Many of the modes of failure are due to wear and tear or extreme conditions such as great wetness or heat. Our product that we design should emulate the design of the radio but we will seek improvement. Some areas we intend to improve on are: waterproofing the electronics and microprocessor assemblies; increasing ventilation or heat dissipation from the gears or motor; changing the gear material to prevent wearing; protecting the gears and generator from shocks; change the batteries to prevent acid leaking.
The Kikkerland radio is a very robust product and can operate in diverse areas and conditions and can continue to operate for a long period of time. We believe that by performing Failure Methods and Effects Analysis we can increase the lifetime and reliability of our product to exceed that of the Kikkerland radio.
A summary of the most common failure modes can be found below:
|Part Number||Item||Function||Failure Mode||Effects of Failure||S||Causes of Failure||O||Design Controls||D||RPN||Recommended Actions|
|25||Antenna||Antenna / Signal Reception||Snapping, Breaking, Bending||Low quality signal, possible malfunction||5||Dropping the radio, improper use||3||Antenna is collapsable||1||15||Internatlize antenna into radio or make the antenna flexible|
|27||Crank Arm||Translating manual energy to the gears||Breaking, Bending, Detachment||No more power generated from cranking. Can only power radio with sunlight||6||Bending, dropping, spinning crank too fast||2||Crank is made to be short and thick, hence difficult to break||1||12||Write a warning on the product, use a stronger material|
|18, 22, 26, 31||Electronics / Microprocessors Assemblies||Taking electrical input and determining the appropriate output for each signal||Water damage||Inoperable system||7||Rain, accidental water damage||4||All of the electronics are protected inside the case||4||112||Seal electronics to make them waterproof, write “water warning” on the product|
|17, 18, 22, 26, 31||Electronics / Microprocessors Assemblies, Battery||Taking electrical input and determining the appropriate output for each signal, storing energy||Overheating||Performance is significantly reduced||6||Extended usage, extended sun and high temperature exposure||1||All electronics are protected inside the case||5||30||Add a fan, add a warning sign, add a temperature sensor, add a heat sink|
|10, 12, 14, 16||Gears||Translating crank mechanical energy input to generator||Wear and tear||No more power generation through cranking, significant frictional losses, slipping of gears||6||Extensive use, manufacturing defects||1||Gears are made out of nylon, which is a relatively strong self-lubricating polymer||4||24||Changing gears’ materials. For instance, metals are less susceptible to wear and tear|
|38||Cables||Transferring electrical signal to / from various components||Dropping radio, wear and tear, extended use||Inoperable system||7||Poor manufacturing, overheating, shock damage||3||There are multiple wires with low resistance within each cable||4||84||Use one integrated circuit for all electronic assembly|
|24||On / Off / Volume Indicator||Allowing user to manipulate the volume of the speaker and turn the radio on / off||Breaking||Unable to manipulate the volume of the speaker||5||Overturning knob, forcing knob in the wrong direction||2||The knob is labeled to inform users which direction it can or cannot turn||2||20||Add rubber stopper to constrain the knob motion|
|7||Radio Station Tuner Indicator||Allowing user to manipulate the frequency of the radio||Breaking||Unable to switch radio channels||5||Overturning knob, forcing knob in the wrong direction||2||The knob is labeled to inform users which direction it can or cannot turn||2||20||Add rubber stopper to constrain the knob motion|
|1, 3||Front and Back Case||Holding assembly and speaker together, protecting components||Breaking, coming apart||Aesthetics, exposure of vulnerable components||4||Dropping the radio||5||There are more than one screws holding the front and back case together, decreasing the likeliness to break||2||40||Add shock absorbers to minimize impact|
|4, 5, 40, 41||Speaker plate, cone, magnet, coil||Translating electrical signal into sound||Vibrational stress||Speaker malfunction and inoperable system||7||Playing radio on maximum volume, wear and tear||5||Speaker is made to span the whole hearing range of human||3||105||Add warning to keep volume to 90% of the maximum. Limit volume internally to 90%|
|8, 13, 15||Generator, magnet, shell||Translating rotational energy into electrical energy through magnetic induction||Demagnetization||No more power generated from generator / crank arm||6||High temperature, short circuit||2||Copper coils and magnet come in multiple parts, allowing it to continue to function even when one is not working||8||96||Add insulation around generator, add solar shield / heat sink to generator assembly|
|17||Battery pack||Storing electrical energy||Leaking battery acid||Inoperable system due to water damage and lack of energy storing device||7||Battery discharging, overheating||1||There are two batteries to store energy in and they are stored with additional plastic wrapping around them||9||63||Change to solid state battery|
|26||Headphone jack assembly||Plug for headphones||Breaking, malfunctioning||Headphone option unavailable||3||Hitting headphone jack with small tools (e.g. screwdrivers)||1||The location of the headphone jack makes it unlikely to be damaged with smaller parts||3||9||Add a removable rubber cover to headphone jack|
|19, 20, 32, 33, 34||Assorted screws||Holding components together||Threads are worn out, losing some screws||Repetitive loosening and tightening of screws||3||Softness, malleability of plastic, the size of the screw||3||Screws come in standard sizes making it easier to replace||2||18||Use helicoils, strengthen the case materials around screw points|
Design for Environment (DFE) - EIO-LCA
The production of the solar hand crank radio is the greatest factor in the product’s greenhouse gas emissions. The economic sectors which contribute most heavily to this figure are power generation and supply, iron and steel mills, and semiconductor and related device manufacturing. Most of these emissions are indirect influences on GHG emissions. Potential areas of redesign are discussed in the following sections. A $30 increase in GHG-related taxes would increase the lifetime cost of the product by $0.60, which is about 2% of the product’s cost. The result can be summarized in the table below:
|Category||Item Purchased||Best Match Economic Sector # and Name||Confidence that sector represents item||Reference Unit||Unit consumed per product life||Cost per unit||Lifetime cost||Economy-wide mt Carbondioxide released per $1M of output for the sector||Implied mt Carbondioxide per product life||Carbondioxide tax ($30 / mt)|
|Production||Hand Crank Radio||334310: Audio and video equipment manufacturing||High||Hand Crank Radio||1||$30||$30||549||0.01647||$0.4941|
|Production||Solar Panel||334413: Semiconductor and related device manufacturing||High||Solar Panel||1||$5||$5||603||0.003015||$0.09045|
The solar hand crank radio is composed primarily of injection-molded plastic components, standardized metal screws, and pre-fabricated electronic circuits. Although it operates off the grid, the device fails to be completely “green”. Several modifications could be made to the manufacturing process to decrease the environmental impact of this product. First, the plastic components (of which the material is not specified explicitly by the manufacturer) could be replaced by post-consumer plastic, recyclable plastic, or cellulose-based plastic. Second, the plastic packaging could be replaced with a more environmentally-friendly material such as cardboard. Finally, the amount of soldering could be reduced by utilizing integrated circuits, and the soldering process could involve lead-free solder. As is the case for any product, material reduction is preferred for reducing cost and environmental impact.
The solar hand crank radio has a very confined function: to capture radio signals. While it completes this task with negligible environmental impact, its function could be expanded to reduce the detrimental impact of other devices to the environment. For instance, an alarm clock could be added to enhance functionality. An mp3 input capability could also broaden its user base. To completely replace a bedside clock, the device may additionally need a power cord (which can be removed for off-grid use). Waterproofing would be a final recommendation for increasing functionality. This would also increase the expected life of the product.
End of Life
The solar hand crank radio does not have any purpose when it ceases to function. It is most likely to be disposed of when broken. This is unfortunate due to the harmful effects electronics and batteries can exhibit on the environment. Aside from constructing the assembly from biodegradable or bio-friendly materials, little options remain for extending the life of this device when its original function expires.
In conclusion, the simplest two methods for reducing the solar hand crank radio’s effect on the environment are the use of “greener” materials and the expansion of the product’s functionality.
Team Member Roles
Oscar Chahin: FMEA, Mechanical Analysis, User Study
Evan Gates: DFE, Stakeholders, DFE-IOC
Kartik Goyal: Bill Of Materials and Diagram, Usage, User Study, Mechanical Function
Huan (Steve) Qin: DFMA, DFE-IOC, User Study
Andre Sutanto: Wikipage editor, Bill of Materials, Stakeholders
Carnegie Mellon University Green Design Institute. (2008) Economic Input-Output Life Cycle Assessment (EIO-LCA), US 1997 Industry Benchmark model. <http://www.eiolca.net> Dieter, George E., and Linda C. Schmidt. Engineering Design. 4th Edition. New York, NY: McGraw-Hill, 2009. 707-715. Print.
Images taken from: Figure 1: www.amazon.com/Kikkerland-Dynamo-Solar-Crank-Emergency/dp/B0017S4C26/ref=sr_1_2?ie=UTF8&qid=1346370017&sr=8-2&keywords=