Critical Design ReviewCapstone Lab 2009
Steven Sorenson Anand Suchak John StrueberGreg Smith Kristen Aragon
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
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
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
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
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 $90
ECG 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
CDRSensing component working
First MilestoneFull prototype
Second MilestonePrototype reworked to within size constraints
CapstoneCompletely working Project
John