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Kinkajou Power Supply







Kinkajou Power Supply


Team 4

Matthew Kwiatkowski
ECE Box # 175

Sean Mahoney
ECE Box # 207

Prity Patel
ECE Box # 277

December 18, 2003
i
Table of Contents

1
Executive Summary






1

2
Introduction







2
2.1
Problem Statement





2
2.2
Planned Approach





2
3
Product Specification Generation




3
3.1
Market Research






3
3.2
Customer Requirements





4
3.3
Initial Product Specifications




5
3.4
Final Product Specifications




5
4
Development Product Timeline




6
5
Design Approach






7

5.1
Design Options






7
5.2
Value Criteria of Design Options



7
5.3
Metrics for Value Analysis




7
5.4
Summary of Design Approaches



7
5.5
Specific Module Design Options



8
5.5.1 Current & Voltage Regulator Value Analysis

8
5.5.2 Decision Circuit Value Analysis


9
5.6
Metrics for Value Analysis




10
5.7
Competitors






11
5.8
Capabilities






12
6
Module Descriptions






13
6.1
Module Descriptions





13
6.1.1 Decision Circuit





14
6.1.2 Current & Voltage Regulator



15
6.2
System Integration





16
7
System Testing Results






17
7.1
Decision Circuit Test





17
7.2
Current & Voltage Regulator Test



17
7.3
Final System Test





18
8
Product Results







19
8.1
Product Results






19
8.2
Standard Costs






19
8.3
Product Functionality





20
9
Next Steps and Recommendations




21
Appendix A: Top Level Gantt Chart




22
Appendix B : Task-Specific Gantt Chart




24
Appendix C: Competitors Value Analysis




26
Appendix D: Return On Investment Graph


28
Appendix E: Bill of Materials






30

ii
Table of Figures

Figure 1: Kinkajou Projector Prototype




3

Figure 2: Value Analysis Current & Voltage Regulator


9
Figure 3: Value Decision Circuit





10

Figure 3: System Block Diagram





13

Figure 4: Decision Circuit






14
Figure 5: Voltage and Current Regulator Schematic


15



1
1
Executive Summary




World Education and Design that Matters are both non-profit organizations that help
improve the quality of living in developing countries. Our project will be focusing on a
design both organizations have been working on to improve the literacy rate in Mali. About
62% of the people are illiterate in Mali, which is about 7 million people
(
www.designthatmatters.org). The problem is not because the people in Mali dont want to
be educated. The problem is that they dont have the resources to educate the adults and
children.

World Education and Design that Matters collaborated on the idea of the Kinkajou
Projector, which is a microfilm projector that projects images in the poorly lighted
classrooms. The projector can carry up to 20,000 pages of materials that are stored on a
cassette. Both organizations hope that the Kinkajou Projector will help decrease the illiteracy
rate and help educate the developing countries. This projector will significantly impact the
quality of living for developing countries.

Our design will be focusing on the power supply of the Kinkajou Projector. Our goal
is to design an efficient power supply that will be powered by a 12V rechargeable battery.
Our final prototype of the power supply will roughly cost $15. However, the cost decreases
to $5 when producing the power supply in bulks of a 100 units. The low cost of our product
should create a significant market for our power supply in the future.





2
2
Introduction

2.1
Problem Statement

In the beginning of this project, we were given the following problem statement:

You are to design the power supply for the Kinkajou Projector. The power supply must
provide a constant current to the 5W white LED inside the projector, as well as run a small
DC cooling fan. The input to the power supply will be a nominal 12 Volts from either a
typical automotive battery or a 12 Volt battery pack. The circuit must be as efficient as
possible to extend battery life. In addition, the circuit should indicate when battery voltage is
low and shut itself down if the voltage drops below a certain level. The circuit must be
integrated into the Kinkajou Projector and not add more than 10% to the production cost.
Prototype cost should not exceed $50.
(
http://ece.wpi.edu/~vaz/courses/ee2799/b03/Labs/kinkajou.htm
)

2.2
Planned Approach

The problem statement above requires that we design a power supply that meets the
following criteria:

Drive the 5W white LED with constant current and drive the small DC cooling fan
with constant voltage


Powered by a 12V rechargeable battery


Indicate when the battery voltage is low with an LED


Shuts off automatically when the voltage has dropped below a certain level.


Cost under $5 or less than 10% of the total production cost.

Our market research, presented in section 3 of this report, revealed that there is a great
interest in designing our power supply to be able to operate in all kinds of temperature and
weather conditions. Since our primary market is in Mali, we need to develop a power supply
to withstand extremely hot climate. Our initial design plan varied greatly from the beginning
of this project to the final design. The reasons for the design change will be present in the
sections to follow. The main focus of our plan was to keep it simple, in order to keep cost
low.

3


3
Product Specification Generation

3.1
Market Research
The market for the Kinkajou Projector will be primarily focused in Mali. The way we
conducted our market research was browsing the World Wide Web. In particular, we
browsed through the websites of MIT and Design that Matters to obtain the majority of the
background information that they had already researched. Design that Matters and MIT
worked together as a team to develop the first prototype of the Kinkajou Projector. The
information and resources that the team gathered is open to the public on the World Wide
Web.
The Kinkajou Projector will aid schools and businesses in developing countries that
dont have libraries. The projector will also be able to provide libraries because it can be
used to store a reference library up to 20,000 pages of material. Microfilms are even used in
the library of WPI. The projectors that schools are currently using are so expensive. The
beauty of the Kinkajou Projector is that it will be affordable to all people. The demand for
this product will be tremendous because the projector will be sold for an affordable price. As
you can see, the Kinkajou Projector can be of use for schools and businesses all over the
world.
In Africa alone, over 315 million people don't know how to read. Over 62% of the
population in Mali is illiterate (www.designthatmatters.org). The Kinkajou Projector will
help project teaching materials in the dark classrooms for the adults and children. MIT
succeeded in developing the first prototype. Figure 1 shows the Kinkajou Beta prototype
MIT had developed as their final product. The Kinkajou projector is a battery-driven
projector that projects an image so bright that the adults and the children will all be able to
read in the dark classrooms. The rechargeable batteries will be recharged either by
110/220V, solar power, or human bicycle petal power. De