Preliminary Design Review
Capstone Lab 2009
Steven Sorenson
Greg Smith
Anand Suchak
Kristen Aragon
John Strueber
Overview
Core Functionality
System Breakdown
Risks
Contingency Plans
Possible Extensions
Budget
Division of Labor
Schedule
Questions
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 Control
Previous/Next track
Play/Pause
Volume 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 plane
Data 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 signal
Attenuation will increase as a conductive body
(the user’s hand) is introduced into the field
Level of attenuation will be transformed into a
magnitude that corresponds to the radius of a
circle centered on the receiving electrodes
Intersection of the 4 circles will denote x-y
coordinates
Greg
d1
d2
Rx
Rx
d3
Rx
Tx
d4
Rx
Greg
Needs to control several
things:
Interface sensors
Interpretation
Network devices
Possible song digestion
Possible control signal
transfer/digestion
Needs to have an A to D
converter
Steven
Speed: 20 MHz
SRAM 128 B
Flash: 2 KB
10-bit A-D Converter
Watchdog Timer
2-wire Serial Interface
2 external 19 internal
interrupts
Steven
Features needed of the battery:
Be light weight and small in size
Retain charge for a long period of time
Be rechargeable
Have a voltage of above 6 volts
Steven
The battery that will use is a
Polymer Lithium Ion Battery
Specifications:
Weight: 0.77oz
Dimensions: 0.23x1.32x1.86”
3.7 V at 1100mAh
Will need two
Steven
Serial Communication bus between
microcontroller and Bluetooth modem
Transmits media player control signals using
AVRCP Bluetooth protocol
Our Bluetooth will pair with the Bluetooth
receiver embedded on the phone
John
BlueSMiRF Gold Modem
Works for TX/RX from 9600 to
115200bps
Specifications
Power Consumption: 25mA
Operating Voltage:3.3V-6V
Frequency: 2.4-2.524GHz
Serial Communication:2400-115200bps
John
Electromagnetic fields caused by surroundings
Weather/Shock Proofing
Inadequate resolution of sensing fields
John
Sensors
Revert to less complex sensing technique
(accelerometer glove)
Bluetooth interference with sensing device
May have to go to USB
Interfacing with T-Mobile G1 Android
John
Interface with smart phone
Implement new gestures for more controls such
as receive calls
GPS tracking and mapping
Means of controlling peripheral device
Gaming on Android
Kristen
Component
Product
Quantity Cost
Microcontroller
AVR ATTiny261
3
$7.50
4
$132
PCBs
Flash Memory (1Mb)
$65
Bluetooth Modem
BlueSMiRF Gold (WRL-00582)
1
$65
Android Phone
T-Mobile G1
1
$200
1
$2
2
$25
?
$150
Push Button
Battery Lithium Ion
Housing
Components
Polymer Lithium Ion
Miscellaneous Parts
$200
Estimated total
$1000
Calculated total ATM
$839
Kristen
Kristen
Greg
Sensing
X
X
Power Management
X
Phone Interface
John
Anand
X
Microcontroller
Wireless
Steven
X
X
X
X
X
X
Kristen
Kristen
CDR
Sensing component working
First Milestone
Full prototype
Second Milestone
Prototype reworked to within size constraints
Capstone
Completely working Project