(1.9 MB PowerPoint)

Preliminary Design ReviewCapstone Lab 2009

Steven Sorenson Anand Suchak John StrueberGreg Smith Kristen Aragon

OverviewCore FunctionalitySystem BreakdownRisksContingency PlansPossible ExtensionsBudgetDivision of LaborScheduleQuestions

Anand

We will be creating an interface for a G1 Android phone to allow for button-less control.The sensing device will track the user’s hand gestures to control basic phone functions.This would be useful in situations where you cannot easily access the phone i.e. skiing, snowboarding, running, etc.

Anand

Song ControlPrevious/Next track Play/PauseVolume Up/Down

Wireless Control

Anand

Greg

Changes in the electric field sensed by an array of transmit and receive electrodes will be used to pinpoint the user’s hand in an x-y planeData stored in SRAM (no refresh cycles, data buses are directly accessible)Trilateration calculations on the collected data will be performed in firmware and compared with LUTs

Greg

The signal received by the receive electrode will be an attenuated and phase shifted version of the transmitted signalAttenuation will increase as a conductive body (the user’s hand) is introduced into the fieldLevel of attenuation will be transformed into a magnitude that corresponds to the radius of a circle centered on the receiving electrodesIntersection of the 4 circles will denote x-y coordinates

Greg

RxRx

Rx Rx

Tx

d2

d1

d3

d4

Greg

Needs to control several things:

Interface sensorsInterpretation

Network devicesPossible song digestionPossible control signal transfer/digestion

Needs to have an A to D converter

Steven

Speed: 20 MHzSRAM 128 BFlash: 2 KB10-bit A-D ConverterWatchdog Timer2-wire Serial Interface2 external 19 internal interrupts

Steven

Features needed of the battery:Be light weight and small in sizeRetain charge for a long period of timeBe rechargeableHave a voltage of above 6 volts

Steven

The battery that will use is a Polymer Lithium Ion BatterySpecifications:

Weight: 0.77ozDimensions: 0.23x1.32x1.86”3.7 V at 1100mAh

Will need two

Steven

Serial Communication bus between microcontroller and Bluetooth modemTransmits media player control signals using AVRCP Bluetooth protocolOur Bluetooth will pair with the Bluetooth receiver embedded on the phone

John

BlueSMiRF Gold ModemWorks for TX/RX from 9600 to 115200bps

SpecificationsPower Consumption: 25mAOperating Voltage:3.3V-6VFrequency: 2.4-2.524GHzSerial Communication:2400-115200bps

John

Electromagnetic fields caused by surroundingsWeather/Shock ProofingInadequate resolution of sensing fields

John

SensorsRevert to less complex sensing technique (accelerometer glove)

Bluetooth interference with sensing deviceMay have to go to USB

Interfacing with T-Mobile G1 Android

John

Interface with smart phoneImplement new gestures for more controls such as receive callsGPS tracking and mappingMeans of controlling peripheral deviceGaming on Android

Kristen

Component Product Quantity Cost

Microcontroller AVR ATTiny261 3 $7.50

PCBs 4 $132

Flash Memory (1Mb) $65

Bluetooth Modem BlueSMiRF Gold (WRL-00582) 1 $65

Android Phone T-Mobile G1 1 $200

Push Button 1 $2

Battery Lithium Ion Polymer Lithium Ion 2 $25

Housing Components

? $150

Miscellaneous Parts $200

Estimated total $1000

Calculated total ATM $839

Kristen

Kristen

Kristen

CDRSensing component working

First MilestoneFull prototype

Second MilestonePrototype reworked to within size constraints

CapstoneCompletely working Project