Its all about fun with sensors Amit Gaur

Its all about fun with sensors!! Amit Gaur

Outline n n n Description of Accelerometer based sensors Bluetooth Technology and Blue. Sentry Data Collection from Blue. Sentry Applications Research Challenges Further Work

Motivation for studying acceleration n n 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 n n Sensor to measure rate of change of velocity Mass-spring system based on Newton’s 2 nd Law & Hooke’s Law Capacitor to measure displacement http: //ccrmawww. stanford. edu/CCR MA/Courses/252/sensor s/node 9. html

Crossbow Accelerometer n n n Silicon micromachined capicitive beam General Purpose 3 Axis Measures accelerations upto 4 g

Other types of accelerometers n n 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 n n n Blue Teeth? ? What are we talking about? Harald Blåtand – 10 th Century Viking King Literal translated to “Bluetooth”

Bluetooth for the Real World n n n 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 Scatternet Piconets Master / Slave Piconet Scatter. Net Bluetooth Piconet and Scatternet formation Ref: www. ccng. uwaterloo. ca/Seminars/Presentations/bilm. ppt

Advantages of using Bluetooth n n n n 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 n Fax Profile n Generic Access Profile n LAN Access Profile n Service Discovery Profile n Generic Object Exchange Profile n Cordless Telephony Profile n Object Push Profile n Intercom Profile n File Transfer Profile n Serial Port Profile n Synchronization Profile n Headset Profile n Dial-up Networking Profile For more on Profiles: http: //www. swedetrack. com/usblue 4. ht m

Blue. Sentry™: Bluetooth™ Sensor Adapter n n n Data Acquisition and Control Module 8 channel 16 bit Ato. D converter Samples analog signals and converts to a Bluetooth enabled digital data stream

Features and Specifications

Bluetooth: Serial Port Profile n n 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 RS 232 control signalling (RS 232 is the standard protocol used in serial port communication) This profile ensures that data rates up to 128 kbit/sec.

Programming Environment n n Application developed on HP i. PAQ with Microsoft Pocket PC 2003(OS) Developer used: Microsoft Embedded Visual C++ Sensor Data collected from Blue. Sentry using Serial Port Programming Data cleaning done using Perl and Python Scripts

Applications 1. 2. 3. Location Based Services Gesture Recognition Applications in Gaming

Overview of Localization Techniques n n n 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. 11 b protocol for wireless communication. The IEEE 802. 11 b wireless Ethernet standard has been deployed in office buildings, museums, hospitals, shopping centers and other indoor environments

Ekahau Positioning System n n n 802. 11 b Wireless Positioning Engine Developed at the Univ of Helsinki Tracking algorithm based on Received Signal Strength Intensity from Wireless Access Points

Improving Localization Performance n 1. 2. All localization services have shortcomings: Access point problems: rogue access points, weak/absence of signal strength: signal strength available only in certain areas Errors in accuracy due to signal fading, multipath

Navasync Experiment Accel x Accel y Accel z Wireless x Wireless y Wireless Speed

Analysis of Accelerometer Data

Applications: Biometrics Gesture Passwords

Gesture based Interaction n Home appliance control with gestures

Simple Application to Gaming: Arkanoid n n n Aim: To control paddle via accelerometer Game is played on the IPAQ Accelerometer serves as a wireless joystick

Further Work n 1. 2. 3. Develop online streaming application for data collection, cleaning, analysis and feedback for the following: Improved localization (using data/sensor fusion techniques) Online gesture recognition system 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? n Gesture recognition: Training required for gesture, same applies for the game application n

Key Takeaways so far…. n n n Familiarity with devices: Accelerometer, Blue. Sentry , i. PAQs Working with sensor streams Sensor Fusion : Multi Sensor Data Collection And……I have miles to go before I sleep.

References n n n http: //www. palowireless. com/infotooth/ Bluetooth. org http: //www. vtt. fi/ict/publications/plomp _et_ailisto_030821. pdf Survey and Taxonomy of Location Systems for Ubiquitous Computing: Hightower and Borrielo Miscellaneous web references