Presentation_BTBox_2012
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Transcript of Presentation_BTBox_2012
BT-BOXBen Valdovinos
Overview• The BT-Box is a general purpose Bluetooth based data
acquisition system that connects computers or smart phone to sensors
• Applications in the medical field• Fall Detection
• Applications in the environmental field• Temperature and humidity sensing
• BT-Box’s technology is general purpose and its applications are very diverse
Requirements• Small size: 3.5” x 2.5” x 0.75”• Bluetooth communication between BT-Box and
computer/phone• Data storage on micro SD card• Accepts different sensors and is reprogrammable• System runs on re-chargeable battery• Implement Fall-Detection Algorithm• Design PCB to place all components in small area• Optional: Development of smart phone interface
BT-Box
A whole system is being created
Small enough to be worn at the waistline when used for Fall
Detecting
System Level Block Diagram
Existing • ioBridge
• Internet-enable anything!• Attach sensors/actuators to a web
gateway or module and control via cloud services
• 100$
• Life Alert• Summon help at the push of a button• Limited to in/around home
Microcontroller
BrandOperating
VoltageClock Speed
Flash Memory
RTCCIO
PinsPrice
Microchip PIC32MX3XX
3.380
MHz128 KB Yes 85 5.17
Flexis Coldfire MCF21X
3.366
MHz128 KB No 134 3.21
Atmel AT32UC3A01
283.3
66 MHz
128 KB Yes 144 4.40
Analog ADUC7060
3.310
MHz32 KB No 14 5.15
Accelerometer• ADXL345 from “Analog Devices”• 3mm x 5mm x 1mm• 23uA in measurement mode and 0.1uA in standby mode
at 2.5 V• 3-axis measurement with 10-bit resolution• Up to 16g (1° accuracy)• Embedded memory with FIFO technology• Activity/inactivity monitoring • Single and double-tap detection as well as free-fall
detection
Memory Card
Type Size (mm) Weight (g)Max Transfer
Rate (SPI)Supply Voltage
SD 32 x 24 x 2.1 2 25 Mbit/sec 3.3
mini SD 21.5 x 1.4 0.8 50 Mbit/sec 3.3
micro SD 11 x 15 x 1 0.25 50 Mbit/sec 3.3
Rechargeable Batteries
Type Output Capacity Size (mm) Price
Lithium Ion 3.7 V 1000 mAh50.8 x 33.5 x
5.9 11.00
Ni-Cd AA 1.2 V 1200 mAh 50 x 10.5 dia. 1.55
Ni-MH AA 1.2 V 2500 mAh 50 x 10.5 dia. 3.99
http://www.batteryspace.com
Bluetooth Module• For future works, connection to smart
phones will be easier with Bluetooth• Adds usability, convenience, and ease-of-use• Range is not an issue• Buying a module is faster than designing my own PCB
• flash, crystal, filters, antenna, and amplifiers included in RN-42
Bluetooth
WT12 WT41 WT21 RN-41 RN-42
TX POWER 3 dBm 19 dBm 7 dBm 15 dBm 4 dBm
CLASS 2 1 1.5 1 2
RANGE 30m 500-1000m 100-200m 100m Max 20m
OP. VOLT 3.3 3.3 1.8-3.6 3.3 2.7-3.0
Sleep Mode 1 mA 3.0 mA 1.5 mA 2.5 mA 0.026 mA
Power 2 mW 79 mW 5 mW 31.6 mW 2.5 mW
SIZE (mm) 26x14x2.4 35x14x3.5 17x11x2.6 19x13.4x2 13.4x26x2
Software Hardware• Microchp’s MPLAB IDE
• C++ • Microcontroller programming
• Python version 2.6• Computer• Bluez
• Eagle • PCB Design
• Bluetooth Module• Micro SD card• USB • Battery • MCU• Accelerometer
Experimental Results• Accelerometer interfacing with microcontroller• Save to SD Card• Bluetooth file transfer established between smart phone
and computer using Linux
Risks & Challenges• Bluetooth implementation• Minimizing size and power consumption• Perfecting the Fall Detection Algorithm• Designing the PCB with Eagle• Working with a 32-bit MCU
EE Courses• Microcontrollers – ES 310• Electronics – ES 330/230• Wireless Communications – ES 485-03• Intro to Antenna Theory – ES 485-01• Analog and Digital Communications – ES 442• Electromagnetic Theory – ES 430
Preliminary Costs• Uno32 Chipkit• ADXL345 Breakout Board
Bill of MaterialsItem Cost Acquired
MCU $5.17 NO
ADXL345 Accelerometer $14.95 NO
RN-42 Evaluation Board $40.00 NO
SanDisk micro SD $4.00 NO
micro SD Socket $3.95 NO
Lithium Ion Battery $11.95 NO
USB Connector $1.20 NO
USB LiPoly Charger $14.95 NO
PCB $169.00 NO
RN-240M $59.00 NO
TOTAL $324.17
Schedule
MCU Programming Environment Ready
Fall Detection Complete
Save Data on SD Card
Bluetooth Works
Assemble Box
References• Microchip website: http://www.microchip.com • Dr. Farahmand’s website:
http://www.sonoma.edu/users/f/farahman/ • SD Group Technical Committee, SD Card Specifications:
Physical Layer, Version 3.01
Advisors• Project Advisor: Professor Jack Ou• Industry Mentor:
Questions?• www.benvaldo.com/senior-project-blog
Basic Data Packet
Access Code Header PayloadPreamb
leSync Word
Trailer AM_ADDR TYPE FLOW ARQN SEQN HEC DATA
4 64 4 3 4 1 1 1 8 0-XXX
Accelerometer Data Payload
Header Board ID # Time Event
8 8 64 8
Accelerometer
Accelerometer fall detection• 8 interrupts
DATA_READY, SINGLE_TAP, DOUBLE_TAP, ACTIVITY, INACTIVITY, FREE_FALL, WATERMARK, and OVERRUN
• Algorithm• Determine the start of the fall• Detect impact, which has
largest impact• Aftermath: body doesn’t rise
immediately• Comparing orientation
before and after.
Algorithm
RTCC• 24-Hour Format (Military Time)• Visibility of One-Half-Second Period• Provides Calendar: Weekday, Date, Month and Year• Alarm Intervals are configurable for Half of a Second, One
Second, 10 Seconds, One Minute, 10 Minutes, One Hour, One Day, One Week, One Month and One Year
• Alarm Repeat with Decrementing
SD card specifics• Initial communication through synchronous one-bit
interface• Host provides clock signal and can command card to
use different operating voltage• Host prepares card for read/write of data block• SDHC and SDXC cards can operate at 1.8-volt• Formatting
• For SDSC cards: FAT16• For SDHC cards: FAT32
• Power use 66-330mW (20-100mA) @ 3.3-V• Max transfer of 50-Mbit/sec
Function boards• Power, Ground, and various I/O ports• Will be encased inside box• Automatically identified by microcontroller
Microcontroller• PIC32MX320F128H• 128K Flash Memory, 128 KB Program Memory
• Processing power needed for Fall Detection
• 2 internal oscillators• 2 SPI, 2 I2C• 16 ADC Channels, 85 I/O Pins• Other Microchip 32-bit MCU’s are viable option• Much room for further project development