Critical Design ReviewCapstone Lab 2009

Steven Sorenson Anand Suchak John StrueberGreg Smith Kristen Aragon

OverviewCore FunctionalitySystem BreakdownRisksBudgetDivision of LaborScheduleQuestions

Kristen

We will be creating an interface for a mp3 player to allow for button-less control.We will also be creating a perfomance data collector that will keep track of position, heart rate, g-forces and accidents.This would be useful in situations where you cannot easily access the mp3 player and it will also provide the user with feedback from the day.

Kristen

Song ControlPrevious/Next track Play/PauseVolume Up/Down

Wireless Control Monitoring

GPSHeart Rate MonitorAccelerometers Pressure Sensors

Kristen

John

Using two ATTiny µcsOne operating as Master of I2C, other as Slave

On-chip UARTs dedicated to Bluetooth and GPS modulesNeed one more UART for SD card memory

Using Phillips SC16IS740 bridge connected to I2C bus

EFI and ECG sensors will interface over ADC

John

Steven

Steven

Steven

SiRF Star III chipsetAntenna Gain: 3.5dBLow power:3.3 V at 75 mA

Outputs NMEA sentences over serial connectionMaster µc will parse NMEA to extract location & time data

Anand

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

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

Anand

Anand

LG Rumor IIGoogle G1 Android

Both support AVRCP Bluetooth protocol

Anand

Kristen

Kristen

Single supply CMOS operational Amplifier

Low Offset Voltage 5µV (max)Zero Drift 0.05µV/°C (max)Single-Supply OperationMicroSize Packaging

Kristen

Micro-Power, Zero-Drift, Rail-to-Rail Out Instrumentation Amplifier

Low Offset Voltage 25µV (max)Low Drift 0.1µV/°CLow Noise 50nV/Built in RFI filtered inputsMicro Power Microsize

Kristen

Proximity detection by measuring capacitanceMC33941 generates a high purity e-field by emitting a sine wave at a low frequency (125kHz)Measuring attenuations suffered by this field

When an object is brought close to an electrode an electric path is formedThis produces a change in e-field currentSensor measures the AC impedance of the generated e-field and outputs a DC voltageExternal microcontroller then processes the signal

Greg

Greg

Greg

Greg

Greg

Greg

Greg

Greg

Greg

Electromagnetic fields caused by surroundingsWeather/Shock ProofingInadequate resolution of sensing fieldsNot being able to reduce size to what we wantAccelerometer might not function well in low temperatures

Anand

Component Product Quantity Cost

Central Microcontroller AVR ATTiny261 3 $7.50 Boot Microcontroller MSP430 F2003 1 Donated

Printed Circuit Boards 4 $132

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

Mp3 player 1 $50

Push Button 1 $2

Battery Lithium Ion Polymer Lithium Ion 11.1V 2000mAh 1 $40

Housing Components and Miscellaneous

Acrylic, Velcro, Polystyrene, Copper wire,

- $150

Electric Field Sensor MC33941 2 Donated Pressure Sensor 1 $5

Development Board for EFI Sensor

KITMC33941EVM 1 $100

Accelerometer ADXL335 1 $16

SRAM KM68257CP-15 1 $8

GPS antenna 20 channel GS405 1 $90ECG Parts INA333, OPA2335, resistors, capacitors $30

Total $693.50

Anand

Anand

Kristen Greg Steven Anand John

Electro Field Imaging X L

Phone Interface L

Boot Sensors X L

Power L X

Boot Microcontroller L

Wireless L X

ECG L

GPS L

Chest Microcontroller

L

Data Storage L

John

CDRSensing component working

First MilestoneFull prototype

Second MilestonePrototype reworked to within size constraints

CapstoneCompletely working Project

John