Hand crank radio

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Revision as of 12:53, 17 September 2012

Figure 1. Kikkerland Dynamo Solar and Crank Emergency Radio, Green

Executive Summary

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.

Consumers

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
• Size
• Durability & reliability
• Efficiency of solar cell & crank (i.e. number of rotations to minutes of radio time)
• Ease of use
• Weatherproof
• 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

Manufacturers

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.

• Lightweight
• Ease of storage (e.g. stackability)
• Durability
• High demand (e.g. large shipment quantities)

Usage

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.

Figure 2. Front View.

Figure 3. Side View.

Figure 4. Back View.

Figure 5. Top View.

Figure 6. As shown, the red light turns on when the battery is charging.

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:

1. 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

1. Turn the On/Off/Volume dial
2. Change frequencies by switching the AM/FM/WB switch
3. Turn tuning dial to change stations
4. 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

User Studies

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:

1. Direct sunlight is needed for the panels to absorb sunlight efficiently
2. Antenna for the radio goes straight up, it does not bend
3. 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
4. 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
5. 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

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

Assembly Diagram

Mechanical Function

Figure 6. Front (above) and side (below) views. Gear 1 receives input from the manual crank and gear 4 sends output to the generator.

Figure 7. Outer shell of generator is lined with a magnet. The copper coils remain fixed while the shell rotates, alternating the magnetic field and inducing a current.

The mechanical aspect is comprised of the generator-crank system. The basic structure is as follows (please refer to figure 6 for gear reference).

The hand crank is basically a shaft which is connected to gear 1 on one end and has the other end free to rotate manually by the user. By having this shaft extend out, the user can easily turn the crank and input more power into the gear system. The gear system is composed of four gears with gear 1 receiving input from the crank and gear 4 connecting to a shaft, which rotates the generator shell. With this rotation, a magnetic field is constantly changing which then generates a current as given by Faraday’s Law of Induction.

Faster rotations generate more current; therefore, the gear system is designed to have a higher power input from the user that is then converted into a lower power, but higher speed output into the generator. Therefore, when the user wishes to play the radio, they must manually turn the crank in order to alternate the magnetic field, which will provide current to the batteries and power the radio.

Design for Manufacturing and Assembly (DFMA)

Failure Modes and Effects Analysis (FMEA)

Design for Environment (DFE)

Manufacturing

Use

End of Life

DFE Conclusions

Mechanical Analysis

Team Member Roles

References

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=