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Its all about fun with sensors!!. Amit Gaur. Outline . Description of Accelerometer based sensors Bluetooth Technology and BlueSentry Data Collection from BlueSentry Applications Research Challenges Further Work. Motivation for studying acceleration. Accelerometers - PowerPoint PPT Presentation
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Its all about fun with sensors!!
Amit Gaur
Outline
Description of Accelerometer based sensors
Bluetooth Technology and BlueSentry
Data Collection from BlueSentry Applications Research Challenges Further Work
Motivation for studying acceleration Accelerometers are used universally for the analysis of acceleration, velocity, and
displacement monitor the vibration level monitor and predict the health and condition of moving machinery Applications: Game Controllers Ultra-sensitive accelerometers : in personal computing devices
and handsets, eg accelerometer enable single-handed menu scrolling, map panning or web browsing without the use of a stylus or push buttons.
Designers of sports and health-related devices : pedometers and calorie counters for step counting, distance traveled and speed measurements.
Portable blood pressure monitoring devices to ensure proper arm positioning.
Used to measure the acceleration undergone by satellites
Accelerometers Sensor to measure
rate of change of velocity
Mass-spring system based on Newton’s 2nd Law & Hooke’s Law
Capacitor to measure displacement
http://ccrma-www.stanford.edu/CCRMA/Courses/252/sensors/node9.html
Crossbow Accelerometer Silicon
micromachined capicitive beam
General Purpose 3 Axis
Measures accelerations upto 4g
Other types of accelerometers piezoelectric accelerometer : based on
the property exhibited by certain crystals where a voltage is generated across the crystal when stressed.
Gyrometers: measure angular acceleration
Optical Accelerometers: use optical sensors
Heat Convection based
Bluetooth
Blue Teeth?? What are we talking about?
Harald Blåtand – 10th Century Viking King
Literal translated to “Bluetooth”
Bluetooth for the Real World short-range wireless communication technology Frequency hopping spread radio technology Wireless connection between devices changes frequency at
fixed intervals of time Master slave connection model Master determines timing of hopping, selection and sequence
of frequencies used.
BT Topology
Master
Slave
Piconet
ScatterNet
Bluetooth Piconet and Scatternet formation
Master / Slave
Scatternet Piconets
Ref:www.ccng.uwaterloo.ca/Seminars/Presentations/bilm.ppt
Advantages of using Bluetooth Allows tranmission range of upto 100
metres Not limited by line of sight Low power consumption Standardized protocol allowing for easy
interoperability Bidirectional mode Reduces the clutter of wires and
associated hazardous connections. Guarantee of data transmission by
acknowledgement system.
Bluetooth Profiles Wide variety of available services Generic Access Profile
Service Discovery Profile
Cordless Telephony Profile
Intercom Profile
Serial Port Profile
Headset Profile
Dial-up Networking Profile
For more on Profiles: http://www.swedetrack.com/usblue4.htm
Fax Profile
LAN Access Profile
Generic Object Exchange Profile
Object Push Profile
File Transfer Profile
Synchronization Profile
BlueSentry™: Bluetooth™ Sensor Adapter
Data Acquisition and Control Module 8 channel 16 bit AtoD converter Samples analog signals and converts to a
Bluetooth enabled digital data stream
Features and Specifications
Bluetooth: Serial Port Profile defines how to set-up virtual serial ports on
two devices and connecting these with Bluetooth.
forms the basis of a number of other profiles, such as dial-up networking, generic object exchange, and object push
Using this profile provides the Bluetooth units with an emulation of a serial cable using RS232 control signalling (RS232 is the standard protocol used in serial port communication)
This profile ensures that data rates up to 128 kbit/sec.
Programming Environment
Application developed on HP iPAQ with Microsoft Pocket PC 2003(OS)
Developer used: Microsoft Embedded Visual C++
Sensor Data collected from BlueSentry using Serial Port Programming
Data cleaning done using Perl and Python Scripts
Applications
1. Location Based Services2. Gesture Recognition3. Applications in Gaming
Overview of Localization Techniques Emerging mobile computing
applications often need to know where things are physically located.
mobile devices such as mobile robots, laptops and PDAs already use 802.11b protocol for wireless communication.
The IEEE 802.11b wireless Ethernet standard has been deployed in office buildings, museums, hospitals, shopping centers and other indoor environments
Ekahau Positioning System
802.11b Wireless Positioning Engine
Developed at the Univ of Helsinki
Tracking algorithm based on Received Signal Strength Intensity from Wireless Access Points
Improving Localization Performance All localization services have
shortcomings:1. Access point problems: rogue
access points, weak/absence of signal strength:signal strength available only in certain areas
2. Errors in accuracy due to signal fading, multipath
Navasync Experiment
Accel x
Accel yAccel z
Wireless xWireless y
Wireless Speed
Analysis of Accelerometer Data
Applications: BiometricsGesture Passwords
Gesture based Interaction Home appliance control with gestures
Simple Application to Gaming:Arkanoid
Aim: To control paddle via accelerometer
Game is played on the IPAQ
Accelerometer serves as a wireless joystick
Further Work Develop online streaming
application for data collection, cleaning, analysis and feedback for the following:
1. Improved localization (using data/sensor fusion techniques)
2. Online gesture recognition system3. Controlling paddle ball using
accelerometer
Work Ahead Sensor Fusion: Develop a model for
interpreting input from Localization Program as well accelerometer/sound sensor.
Eg. Which sensor stream is more reliable and when?
Gesture recognition: Training required for gesture, same applies for the game application
Key Takeaways so far….
Familiarity with devices: Accelerometer, BlueSentry , iPAQs
Working with sensor streams Sensor Fusion : Multi Sensor Data
Collection
And……I have miles to go before I sleep.
References http://www.palowireless.com/
infotooth/ Bluetooth.org http://www.vtt.fi/ict/publications/pl
omp_et_ailisto_030821.pdf Survey and Taxonomy of Location
Systems for Ubiquitous Computing: Hightower and Borrielo
Miscellaneous web references