DT3: Solar-Powered “Connect-on-Demand” Satellite/Radio link for Tanzanian Schools

Luis GarciaEric HatchJoe LarsenMichael MoultonRafael OcampoRodney Singleton

Outline

Background Overview Design Design Criteria Risks Costs

Background Joint project with Electrical

Engineering and Telecommunications

Supply internet access to rural schools in Tanzania

Past projects focused on time sharing computer systems

Currently implementations• Baraka Primary School• Manyara Secondary School

VSAT to the internet is at Baraka Baraka is reliant on solar power Team 4 will be installing a third

installation at Rift Valley Secondary School

Rift ValleyBaraka

Manyara

5 - 6 miles

2 Miles

Overview of Design

WiMAX

AM radio

AM transmitter AM

reciever

decoder

modem

router

microcontroller

Battery charge controller

Software Design software that will determine if a request for

the internet has been made by the user. Save packets during request before internet boot-

up, and send once a connection has been established.

Generate signal to be sent to transmitter for turning on network equipment.

AM Radio

Send Signal from Manyara or Rift Valley to Baraka

Transmitters at Manyara and Rift Valley Receiver at Baraka

• Low Power Consumption Operating on 462MHz

• Availability• Antenna design

Decoder Tone Signals Prevent unwanted requests

Microcontroller Function

Will be used to turn off/on the sub-system using relays. Will take in 4 inputs:

Battery life• Less than 40%

Reset Timer• 15 minute timeout

Internet Request• Requests from either Manyara, Rift Valley or

Baraka Internal Clock

• 11pm curfew

Design Criteria

Order of Priorities:1. Low Power

Consumption2. Robustness/Durability3. Low Maintenance4. Safety5. Low Cost

Risk Management

Multiple external timers, risk of power consumption.

Remote diagnosing? Safety of equipment. Collaboration for multi-seat deployments.

Cost

Hardware: Programmable Timers: $5 – $10 Micro Controller: $0 Am transmitter and receiver: $12 – $80 3 Op Amp: $6 – $10 WiMax: $1,900 Wires: $15 – $30 Power Strip: $6 – $20 Project Enclosures: $10 – $80

Software: Python - $0 Libpcap - $0 All Software is open source

In Summary

We plan to design an “Connect-on-Demand” internet interface to which students can access the internet at night if necessary. This design will be power efficient and beneficial to the education of the Tanzanian students of all three schools.