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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