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Presentation_BTBox_2012
The BT-Box is a small Bluetooth data acquisition system that connects sensors to computers or smartphones. It can be used for medical applications like fall detection and environmental applications like temperature and humidity sensing. The BT-Box uses a microcontroller, Bluetooth module, accelerometer, memory card, and battery. An algorithm will be implemented to detect falls using data from the accelerometer. The system will be designed to be small, low power, and support different sensors.
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Presentation_BTBox_2012
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- 2. Overview • The BT-Boxis 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
- 3. 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
- 4. BT-Box Small enough to be worn at the waistline when used for Fall Detecting A whole system is being created
- 5. System Level BlockDiagram
- 6. 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
- 7. Microcontroller Operating Clock Flash IO Brand RTCC Price Voltage Speed Memory Pins Microchip 80 3.3 128 KB Yes 85 5.17 PIC32MX3XX MHz Flexis Coldfire 66 3.3 128 KB No 134 3.21 MCF21X MHz Atmel 66 AT32UC3A01 3.3 128 KB Yes 144 4.40 MHz 28 Analog 10 3.3 32 KB No 14 5.15 ADUC7060 MHz
- 8. 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
- 9. Memory Card Max Transfer Supply Type Size (mm) Weight (g) Rate (SPI) 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
- 10. Rechargeable Batteries Type Output Capacity Size (mm) Price 50.8 x 33.5 x Lithium Ion 3.7 V 1000 mAh 11.00 5.9 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
- 11. Bluetooth Module • Forfuture 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
- 12. 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
- 13. Software Hardware • Microchp’s MPLAB IDE • Bluetooth Module • C++ • Micro SD card • Microcontroller programming • USB • Python version 2.6 • Battery • Computer • MCU • Bluez • Accelerometer • Eagle • PCB Design
- 14. Experimental Results • Accelerometerinterfacing with microcontroller • Save to SD Card • Bluetooth file transfer established between smart phone and computer using Linux
- 15. 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
- 16. 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
- 17. Preliminary Costs • Uno32Chipkit • ADXL345 Breakout Board
- 18. Bill of Materials Item 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
- 19. Schedule MCU Programming Environment Ready Fall Detection Complete Bluetooth Save Data on Works SD Card Assemble Box
- 20. 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
- 21. Advisors • Project Advisor:Professor Jack Ou • Industry Mentor:
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- 23. Basic Data Packet Access Code Header Payload Preamb Sync Trailer AM_ADDR TYPE FLOW ARQN SEQN HEC DATA le Word 4 64 4 3 4 1 1 1 8 0-XXX Accelerometer Data Payload Header Board ID # Time Event 8 8 64 8
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- 25. 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.
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- 27. 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
- 28. 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
- 29. Function boards • Power,Ground, and various I/O ports • Will be encased inside box • Automatically identified by microcontroller
- 30. Microcontroller • PIC32MX320F128H • 128KFlash 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
Editor's Notes
- #2 Add an “applications” slide
- #4 Python running on a computer is replacing the cell phone, which is the end goal of another project. There isn’t enough time for the development of an app or application writing. So I will have python script receive data and save to a file.
- #5 Emphasize the size. Where do you wear it. Future works: now I just detect fall. Later I send messages with phone. Make it clear I am making a whole thing here. Emphasize my project last year in 310. picture of where yoy could wear this. How many people fall. Disease. Simple and high level. Still technical. Interesting. Convincing. Whos my audience?
- #7 Iob is not mobile. Look at climate pod….expensive. Mines small, low cost, mobile,
- #8 Microchip: information about mcu is easily available. Somewhat difficult to find info with other websites. Company is known and robust,plus I have experience with them.Fall detection has been done with 60KB
- #9 Great accelerometer for fall detection
- #13 RN-41 and RN-42 both have options for antennaAdd in power usageThese are claimed by the manufacturer
- #14 Add hardwareTools for smart phone
- #26 Single_tap = acceleration in one-axis is above set threshold, for shorter time period than in DUR registerDouble_tap = acceleration in two-axes is above set threshold, for shorter time period than in DUR period