TEAM 2Solar-Powered Multi-Seat Computer Kiosk

for Tanzanian Classrooms

ECE Facilitator Jian RenTelecomm Facilitator Kurt DeMaagd

UDSM Solar Advising Professor Dominick ChambegaUDSM Telecomm Advising Professor Aloys Mvuma

Management Jakub MazurWeb Josh Wong

Document Ben KershnerPresentation/Lab Eric Tarkleson

Telecomm Joe LarsenTelecomm Tor Bjornrud

UDSM Telecomm Victor Crallet

Request for Proposal – October 13th, 2008

Sponsored By:

In Cooperation With:

Michigan State University University of Dar es Salaam

Executive SummaryWith the increasing proliferation of affordable, reliable personal computers

into the marketplace, there is a great demand to develop affordable personal

computers for remote and undeveloped areas. One such potential region is rural

East Africa, specifically Tanzania. Before deploying a computer system into such

harsh conditions, several obstacles must be overcome, including source of

electricity, telecommunications, and the savannah climate. The Lenovo Corporation

has tasked this team to develop a solar-powered computer workstation that can

accommodate up to eight users. The solution must be robust enough to withstand

the harsh environment with as little technical maintenance as possible, yet still be

affordable for rural schools.

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Table of Contents

EXECUTIVE SUMMARY 2

TECHNICAL SPECIFICATIONS 4

INTRODUCTION 4BACKGROUND 4DESIGN SPECIFICATIONS 5DESIGN CRITERIA 5CONCEPTUAL DESIGN 6PHASE I: POWER ARCHITECTURE 7PHASE II: SYSTEM ARCHITECTURE PROTOTYPES 8PHASE III: POWER MANAGEMENT 14PHASE IV: CONTENT 14

PROJECT MANAGEMENT 15

DESIGN TEAMS AND ROLES 15

REFERENCES 16

IMAGES 16NOMENCLATURE 16

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Technical Specifications

IntroductionThe primary goal of this project is to help promote education in developing

countries by providing grade schools with electronic resources. There are a variety

of other groups that have already initiated solutions to this problem. The most

prominent group is the One Laptop Per Child Association (hereinafter referred to as

OLPC), which has created a cheap, durable laptop known as the XO-1. Other groups

such as the Center for Scientific Computing and Free Software (hereinafter referred

to as C3SL) have made significant strides in reusing older computers for schools;

however, both of those programs have some significant drawbacks. 

BackgroundThe primary competitor identified is the OLPC. The OLPC Association is

dedicated to producing low cost laptops and distributing them to low-income areas.

There exist several problems with the program, including the per-deployment cost

and deployment. The original intent was to deliver a laptop to every child for a cost

of $100 per device. The program, however, is unable to deliver the laptop at the

$100 target; in fact, the cost to donate a system is almost $200. Deployments also

require a minimum commitment of 100 laptops. This represents a very significant

financial burden, though once deployed, the XO-1’s are extremely rugged PCs and do

not depend on any external power sources. Once deployed, it is difficult to integrate

multiple PCs into a cohesive learning environment, and this takes away from

educating the students.

C3SL’s solution integrates into school systems better, and was widely

deployed in the Paraná Digital project. This project involved having the multiple

terminals running off of a single computer in multiple schools. This program has

been very successful and shows great promise, but there is a critical flaw. The

program is entirely software, and this software was intended to run in a classroom

equipped with at a minimum basic utilities, such as power and internet-

connectivity.

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Our solution is to integrate the OLPC's ruggedness and the C3SL's novel

software solution into one robust package. The design team preceding ours built a

solar powered computer system that can be deployed in a relatively durable

building. They assembled a solar panel, battery, and a charge controller into a self-

contained solution, such that deployment in a wide variety of climates and locales is

possible, but they were unable to decide on the computer system. Our primary goal

for this project of integrating the work of our predecessors with a computer system

that is suitable for educating youth, regardless of regional or socio-economic

boundaries.

Design SpecificationsThe core of the design is a single computer powering multiple dumb

terminals. There are many ways to create a dumb terminal; these will be discussed

later in the proposal. The entire system is connected to an AC/DC inverter, which is

powered by a large, deep-cycle battery. The battery is charged via a photovoltaic

panel. There is independent monitoring circuitry to ensure the system is functioning

properly, which can gather data to recommend ways of improving system

performance as well.

Once the prototype is complete, we will install it in a school in Tanzania.

Lenovo will also be able to mass-produce the system and package it for sale. A

variety of organizations, such as governments or humanitarian groups, can then

purchase a base station and add any number of terminals. Given that each station

functions independent of a power source or communications source, it can be

shipped to any location and quickly be installed. Once the system is set up, it will

require minimal maintenance, and limited software support will be provided over

the Internet.

Design Criteria The following requirements are established to decide the feasibility and rating

the desirability of the conceptual designs:

Stability/Reliability

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o The system is to operate in a remote area with as little maintenance as

possible.

Power Consumption

o Solar power is the single power source for the system therefore

minimal power consumption is a priority.

Construction Difficulty

o The team has a limited time frame to complete the project and have it

packaged ready for deployment.

Lenovo Hardware

o Implementing the sponsor’s hardware into the system will help keep

costs down.

Cost

o The system is to be implemented in schools with a very limited

budget, the lower the cost the greater the chances of system

deployment.

The criteria (specifications) to be used in the matrices for deciding the

feasibility and rating the desirability of the conceptual designs are still being

developed, and at least one conceptual design.

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Conceptual DesignThe conceptual design for this project is split into four phases. The first is

power system design, which for the most part was completed by the previous

semester’s team, but was still reviewed by our team. The next phase is system

architecture, i.e. how the computers and workstations are set up. After that, we

covered power management, and finally, content.

Phase I: Power Architecture

Figure 1: Power architecture flowchart.

Given that the power architecture was in place when the team received the

project, and that the schedule and budget are limited, we decided to leave it in its

current configuration. A meeting was convened and possible improvements to the

architecture were discussed, which could be considered for the production model.

Starting from the top down is the solar panel. There are two qualities to

consider: efficiency and price. The panel chosen should provide the highest wattage

per dollar spent, giving the greatest value. Several cheap, low efficiency panels

would be preferable to a single high efficiency panel if they provide a higher wattage

per dollar. They would also be more robust; e.g. a single panel could fail and the

system would loose a portion of its power generation capabilities, rather than its

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sole source of power. The panel currently used is the Kyocera KC85TS 85W panel,

which operates at 16% efficiency (see Figure 2 for value).

A mid-range standard charge controller (CirKit SCC3) is used to regulate the

voltage from the solar panel to the battery. The standard charge controller could be

improved by replacing it with a maximum power point tracker (MPPT), which is

more capable of handling the surplus voltage (> 15V) generated by the solar panel

in high irradiance conditions (i.e. direct sunlight).

The battery purchased for the project is a 225 Amp-Hour marine deep-cycle

battery, chosen for its large capacity and ability to delivery current at a constant

voltage for an extended period of time. As in the solar panel, the capacity and price

are the two key qualities in consideration (see Figure 2 for value), the life cycle is

also very important. It tends to not vary throughout the industry with deep-cycle gel

batteries intended for solar use, and therefore did not garner much consideration.

This entire system feeds a 1750W power inverter, which ideally operates at

90% efficiency. From here power can be provided to anything that can operate at

115VAC. This may be an issue depending on the area of deployment; a majority of

the world operates at 220-240VAC, thus interfacing other components into the

power system (such as cell phone chargers) could prove to be dangerous.

Figure 2: Component cost/value table.

Component Model Number

Capacity Efficiency Cost Value

Solar Panel Kyocera KC85TS

85W 16% $468.75 0.181 W/$

Charge Controller

CirKit SCC3 N/A N/A $44.95 N/A

Battery Deka Domintator 8G8D

225AH N/A $399.07 0.564 AH/$

Power Inverter XPower 1750 Plus

1750W 90% N/A N/A

Phase II: System Architecture PrototypesThe ECE team considered four ideas for the architecture of the system.

During a whiteboard brainstorming session, each prototype was sketched, the pros

and cons were weighed, and a cost was estimated, as shown in Figure 3.

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Figure 3: System architecture advantages, disadvantages, and estimated cost table.

Laptops Thin Client Multi-User Blade ClientCost Outline: Baseline:

- Router with advanced features ($200)

Baseline:- Server ($500)

Baseline:- Powerful Server ($800)

Baseline:- Server ($500)

Per Seat:- Lenovo IdeaPad S10 Latop ($439)- Mount ($50)

Per Seat:- Diskless Workstation LTSP 1220PXE Thin Client ($285)- Lenovo L197 Monitor ($239)- Keyboard/ Mouse ($30)

Per Seat:- Lenovo L197 Monitor ($239)- Keyboard/ Mouse ($30)- Video card ($30)- Optional Software ($100)

Per Seat:- Small Motherboard with RAM & CPU ($100)- DC-DC Power Supply ($50)- Keyboard/ Mouse ($30)- Lenovo L197 Monitor ($239)

Total Cost: Base: $200 Base: $500 Base: $800 Base: $500Per Seat: $489 Per Seat: $554 Per Seat: $399 Per Seat: $419

Pros: Easy, Reliable, Server- less, Redundant, Low Power Consumption

Easy, Reliable, Stable, Low Power, COTS

Cheap, Lowest Power Consumption, Single Point of Maintenance, 100% Lenovo Hardware

Possibly Cheaper than Thin Client, 100% Lenovo Hardware

Cons: Small Screens, Defeats Purpose of Designing a New system as Opposed to Donating Laptops, Security Concerns

Relatively Expensive, Lenovo Does not Make a Thin Client

COTS Software is Expensive and Open-Source is Immature, Reliability is Main Concern

Lots of Enclosure Work, Reliability

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Laptop Architecture

Figure 4: Laptop system architecture mock-up.

The first prototype was a simple laptop-server setup. Each workstation

would consist of small laptop (a 10” form factor, such as the Lenovo S10). The

laptops would be connected to the Internet either by an Ethernet cable, or even Wi-

Fi. Laptops could be run without being directly connected to AC power; a charging

station would be setup by the server.

This style of architecture would be very simple to configure. The server and

the laptops would all be off-the-shelf Lenovo products. The workstations would

have low power consumption, given the fact that the monitor, computer, keyboard,

and mouse are all combined into one device. Should a laptop be damaged, it would

also be very easy to replace, requiring little re-configuration, and no custom

engineering.

Ultimately, Lenovo has specified that it does not want to simply hand out

laptops. The laptops pose a security risk, given that they have value on the open

market. Their portability also adds to the security risk. Their all-in-one design also

makes them much harder to repair.

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Multi-Seat Architecture

Figure 5: Multi-user system architecture mock-up.

One of the most attractive architectures is the Linux multi-seat. Based on

some very interesting test cases found, it’s implemented by building a central PC

with multiple video cards (4-8), multiple keyboards, and multiple mice. Each

workstation would be plugged directly into the server, with individual login names

created. .

There would be a very low cost for such a setup. No thin clients would be

required, only a monitor, keyboard, and mouse. The power requirements would also

be lower, given that the CPU and all of its resources would be shared by all of the

users. The system would also respond much quicker than a thin client, without the

LAN bandwidth and latency issues.

There are many websites dedicated to the subject, and the various open

source solutions. Unfortunately, these options are buggy and unstable, at best. A

for-profit company, Userful, has also popped up, offering a Linux-based closed

source solution that is much more reliable than any of the open source solutions

found. Trial versions of their software were found to be very user friendly, if not

somewhat prohibitive. The largest obstacle was the license, at $100 per seat per

year.

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If the software end of this solution were more mature, Team 2 would highly

recommend this architecture, however, given the reliability needed, it would be

unwise to implement. Given work by some computer science students, and the open

source community as a whole, this could develop into the most robust and cost-

effective architecture.

Blade-Client Architecture

Figure 6: Blade-client system architecture mock-up.

Another type of architecture discussed was the blade-client (or DIY thin

client). For all intents and purposes, it is a homemade thin client. Each workstation

consists of a small motherboard (mini ITX), with the accompanying RAM and CPU,

but lacking a hard drive. These would be placed inside of a custom enclosure, and

connected to a small monitor (17” or smaller), keyboard, and mouse. Each

workstation would utilize PXE boot to connect as a thin client to a central server.

The entire system could be built using Lenovo components. Custom

enclosures would have to be built for each workstation, but the cost of a

motherboard, CPU, RAM, and enclosure would be significantly less than a third-

party thin client (especially when taking into consideration Lenovo’s cost vs. market

cost).

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Unfortunately, this system would be the most difficult to implement, given its

the highly customized nature. It would also have slightly higher power

requirements than the traditional, depending on the motherboard and CPU used.

With the high level of customization, it also increases the opportunities for failures

while reducing the reliability, however, Team 2 suggests that Lenovo examine what

resources it would take to build its own production quality thin client.

Thin Client Architecture

Figure 7: Thin client system architecture mock-up.

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Phase III: Power Management            A power management system will be designed to monitor voltage and current

levels at key points in the system and use this information to calculate real-time

data such as percent battery remaining, time until dead battery, and current

charging conditions.

            To implement this system we will use a PIC 18F series microcontroller for all

processing functions. Various voltages can be read using the analog inputs. For

current sensing we are using LEM FHS-40P Hall effect sensors. These sensors

measure the electromagnetic field created from the current flowing through the

wire and convert this to a voltage that the PIC can then calculate the current with.

The PIC will communicate with the server using the serial data bus. This is preferred

over USB because it is easier to implement and is more consistent from platform to

platform. A serial to USB converter would be used if the server lacks a serial port.

The power management system will function with or without the server. An

LCD screen will display pertinent information. More information can be accessed via

several buttons that will allow scrolling through a menu. Several LEDs will display

critical information such as power on, low power, and service needed. When power

becomes critically low (less than 20% charge remaining in the battery) the PIC will

initiate a shutdown sequence which will save important data to the server and then

turn off all of the components safely. Once the system has been charged to an

appropriate level the system will perform as usual.

Phase IV: ContentWith the majority of potential customers being rural persons that often live

in secluded tribes, the content available on the machines must be carefully

controlled in order to protect the identity of the tribe. The Internet will be white

listed, that is, only a select few websites will be available. Also, other education

content, such as digital encyclopedias must be selected to avoid as much Western

bias as possible.

The Telecommunications teams, both at Michigan State University and the

University of Dar es Salaam, have been tasked with seeking out appropriate

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resources to deliver, without compromising the youth by giving access to restricted

content.

The Engineering team will also develop software to assist in integrating the

machines into the classroom, by offering an electronic hand-in. Students can work

on papers on any machine, and then “hand them in” by submitting them to the

central server using our software. The instructor can then review them digitally,

without having to print them off (infeasible) or collect them manually via USB

thumb drive.

Project Management

Design Teams and RolesGiven the size and importance of this project, Team 2 was put together in

three distinct teams:

Engineering (Michigan State University)Member RoleJian Ren FacilitatorJakub Mazur ManagementJosh Wong WebBen Kershner DocumentsEric Tarkleson Presentations/Lab

Telecommunications (Michigan State University)Member RoleKurt DeMaagd FacilitatorJoe Larsen TelecommunicationsTor Bjornrud Telecommunications

Tanzania (University of Dar es Salaam)Member RoleDominick Chambega Solar Advising ProfessorAloys Mvuma Telecommunications Advising ProfessorVictor Claret Telecommunications

References

ImagesAll images on the coversheet were obtained from Wikipedia:

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The Lenovo logo is owned by the Lenovo Group and is being used under the fair-use rationale.

The Michigan State University logo is owned by the Michigan State University Board of Trustees and is being used under the fair-use rationale.

The University of Dar es Salaam logo is owned by the University of Dar es Salaam and is being used under the fair-use rationale.

Nomenclature C3SL – Center for Scientific Computing and Free Software. CPU – Central Processing Unit, refers to the main processor chip on a computer

motherboard, not the computer as a whole. COTS – Commercial Off The Shelf, describes hardware or software that may be

purchased rather than designed and built. MPPT – Maximum Power Point Tracker, a style of solar charge controller. multi-seat – A type of system architecture in which many workstations are built

onto a single machine. PIC – The company that produces the microcontroller used, may also refer to the

microcontroller itself. PV – Photo-Voltaic, i.e. solar panel. PXE – Pre-boot eXecution Environment, a manner of booting computers over the

network without a locally installed operating system. OLPC – One Laptop Per Child. OSS – Open Source Software. system architecture – The term used within this document to describe how the

style in which the workstations are deployed. thin client – A client computer that relies on a central server for a majority of its

processing tasks.

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