TEAM 2 Solar-Powered Multi-Seat Computer Kiosk for Tanzanian Classrooms

TEAM 2
Solar-Powered Multi-Seat Computer Kiosk
for Tanzanian Classrooms

ECE FacilitatorJian Ren

Telecomm FacilitatorKurt DeMaagd

UDSM Solar Advising ProfessorDominick Chambega[BK1]
UDSM Telecomm Advising ProfessorAloys Mvuma[BK2]
[BK3]ManagementJakub Mazur
WebJosh Wong
DocumentBen Kershner
Presentation/LabEric Tarkleson
TelecommJoe Larsen
TelecommTor Bjornrud
UDSM TelecommVictor Crallet[BK4]

Request for Pre-Proposal Draft -– October 13thSeptember 17, 2008

Sponsored By:

In Cooperation With:

Michigan State UniversityUniversity of Dar es Salaam

Executive Summary

With 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.

Table of Contents

Executive Summary

Technical Specifications

Introduction

Background

Design Specifications

Design Criteria

Conceptual Design

Phase I: Power Architecture

Phase II: System Architecture Prototypes

Phase III: Power Management

Phase IV: Content

Project Management

Design Teams and Roles

References

Images

Nomenclature

Executive Summary 2

Technical Specifications 4

Introduction4

Background4

Design Specifications4

Conceptual Design4

System Architecture Prototypes4

Proposed Design Solution5

Risk Analysis 5

Project Management 8

Design Teams and Roles8

Budget6

References 10

Images10

Nomenclature10

Technical Specifications

Introduction

The 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.

Background

The primary goal of our product is to help promote education of the youth of various third world countries. There are lots of other groups that are investigating solutions to the problem. The most prominent group is the One Laptop Per Child Program (OLPC). Other groups such as the Center for Scientific Computing and Free Software (C3SL) have made significant strides in reusing older computer for schools. However, both of those programs have some significant drawbacks.

The primary competitor we haveidentified is the OLPC. The OLPC Association, this program is dedicated to producing low cost laptops andintended for distributing themion to low incomelow-income areas. Our design aims to correct some of the flaws found in the OLPC program. One of the major problems with the OLPC is integrating the educational programs of the countries. There exist several pOther problems with the program, s includinge the per-deployment costt of the program, and deployment. The original intent of the program was to deliver a laptop to every child for a cost of $100 per device. However Tthe program, however, iswas unable to deliver the laptop at the $100 target,; in fact, the cost to donate a system is almostcloser to $200. Deployments also Also, in order to program is requireing a minimum commitment of 100 laptops for deployment in a single area. This represents a very significant financial burden. The primary advantage of th, though once deployed, thee XO-1’s areOLPC system is that the system is extremely rugged PCs and does 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.

The other solution from C3SL’s solution has a much better integrationintegrates into school systems better, and. Their solution 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,. butHowever, there is a critical flaw., Tthe 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.. The target deployment zone for our product does not have basic utilities.

The solution our predecessors came up with was toOur solution is to integrate the OLPC's ruggedness and the C3SL's novel software solution into a single combinedone robust package. Their conceptThe design team preceding ours was abuilt a solar powered computer system that can be deployed in a relatively durable to be deployed in school building. They assembled a solar panel, battery, and a charge controller into a The system would be self-contained solution, such thato deployment in a wide variety of climates and locales is possibleanywhere in the world would be possible, b. They were able to decide on a solar panel, batters, and a charge controller, but they were unable to decide on the computer system. OurOur primary goal for this project is toof integratinge the work of our predecessors did with a computer system that is suitable for educating youth, regardless of regional or socio-economic boundaries. in third world nations.

Design Specifications

The 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 at least onea photovoltaic panel. There is will also be independent monitoring circuitry to ensure the system is performingfunctioning properly, and towhich can gather data to recommend ways of improving system performance as wellimprove the system performance in the next generation.

The idea operation for Once our product is that once we have a designthe prototype is in placecomplete, we will install it in a school in Tanzania. Lenovo will also be able to mass-produce the componentssystem 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 terminalsThis would allow third parties to purchase a system for any number of terminals for any location. Given that each station functions independent of a power source or communications source, it can The system would be assembled in the US, be packed, and shipped to the desiredany location and quickly be installed. where it can be quickly set up. Once the system is set up, it should will require minimal maintenance, and limited software support will be provided over the Internet.. The only reason someone should need to service the system is to replace broken components.

QWERTY

Design Criteria

The following requirements are established to decide the feasibility and rating the desirability of the conceptual designs:.

• Stability/Reliability
• The system is to operate in a remote area with as little maintenance as possible.
• Power Consumption
• Solar power is the single power source for the system therefore minimal power consumption is a priority.
• Construction Difficulty
• The team has a limited time frame to complete the project and have it packaged ready for deployment.
• Lenovo Hardware
• Implementing the sponsor’s hardware into the system will help keep costs down.
• Cost

oThe 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.

Conceptual Design

QWERTYThe 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 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.

Phase II: System Architecture Prototypes

The 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.

.

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

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.

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, , (need to write a complete sentences!) 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 (see appendix), 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.

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).

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 reliabilitythe 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.

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.