BeHāv Student Behavior FeedbackSystem
Overview • Team • BeHāV Overview • Schematic • Parts • Software • Hub • Timeline • Budget
Team Members • Matthew Fargano • Joshua Fedders • Terrell Jones • Nicholas Miller • Mohamed Siddig • Joseph Esler* *Software Systems Development Member
What is BeHāv? • A Wireless System for Modifying Learning Disabled Students Behavior • A System for Tracking the Progress of Learning Disabled Students
Features • Wireless • Small Size • Long Battery Life • Easy to Use Interface
Key Fob • Originally we were considering using pre-programmable key fobs. However, this approach was unwarranted since we would have to reverse engineer the key fobs in order to make our transceiver on the other end communicate with it. Due to the synergy of the project, the key fob transmitter is similar in communication function compared to the receiver. This allows us to produce a transmitter almost directly from our receiver schematic. The major differences are: • Key fob uses 2 buttons • No Buzzer or Display
Microcontroller- MSP430F2272 • Processes incoming events. • Applies timestamp • Stores data • Outputs data to external PC
MSP430F2272 Advantages • Large Flash Memory • 32kB of Flash Memory • Low Power Consumption • UART, SPI, and I2C compatible interfaces • Flash Memory Program Execution
Transceiver- MiRF v2 • Low cost • Low Power (Requires Switch Converter works with 3.3-7 V input) • Works with in our required area (30ft Radius) • 125 Channels (Between 2.4MHz – 2.525 MHz) • Works in Open band (2.4GHz range) • Built in Antenna • Compact size • Readily available • Standby mode to save power
Transceiver- Dev Board • Look at data sent and received over the wireless link. • Can tweak firmware on the MiRF v2 (change channel used) • Preloaded firmware for testing. • Low Cost Dev Board
LED- Score Display • Lite-on LTD-2701 7-segment LED • Lower Power • 7mm digit height • High Contrast • Wide Viewing Angle • Low Cost • Requires BCD
BCD to 7-segment Driver • TI CD4511BE • CMOS • Latches input
Vibrator- DC Motor G13566 • Costs less than $1 when bought in bulk • 11 mm x 4.5 mm • Runs on as low as 1V DC (.05W) • Will require a MOSFET to power
Power Regulator • ADP2105 • Buck Converter • 2.7V - 5.5V input range • 3.3V output • ~96% Efficiency • 1 A max load current
Real Time Clock- MT41T0 Features: • Seconds, minutes, hours, day, date, month, years, and century • 32KHz crystal oscillator • Serial interface supports I2C bus • Low standby current 0.9μA (typ@3V) • 2.0 to 5.5V clock operating voltage
Time Stamp Format
Memory Capacity Flash Memory = 32kB Firmware = 10kB Event Logging Space = 22kB # of Bytes for a event = 555B ___________________________________ # of events that could be recorded = 4553 Or 10 Days of 1 event/min for 8 hours a day
Hub Advantages Single station for devices Hub Disadvantages Limited mobility Higher cost Limited expansion To hub or not to hub?
Proposed USB Connect the Receiver directly to an external PC via USB. • Increased Mobility • Less Expensive • Supports any number of devices
USB Port Interface • Allows communication between our devices and the PC through Mini USB connection. This allows a easier form of programming and data retrieval than original base station design. This connector interfaces directly with the MSP430’s UART. This provides the option to incorporate a rechargeable battery by connection to the USB. • 5 V input from USB bus (for rechargeable battery) • Variable baud rate • 100mA maximum output current
Milestone 1 • Wire wrap constructed system. • Able to receive input from external Key Fob source. • Timestamp and store events in internal flash. • Can retrieve data from system via USB connection.
Milestone 2 • PCB board assembled, debugged, and working. • Displays score through 7-segment LED display. • Data interfaces with Microsoft Excel.
Capstone Expo • Delivers a single unit working BeHāv system with following features. • USB Interface • Time stamped events • 7-segment LED display of current score • Vibrating receiver for feedback
Tasks Mutual Tasks: Documentation, Tech manual, User manual Matt: Transceivers, MSP430 Firmware, and Proto-board lay out Josh: MSP430 Firmware, LED display, BCD Nick: Computer interface, USB, MSP430 Firmware, Real Time Clock Terrel: PCB, Transceivers, Proto-board lay out Mohamed: PCB, Real time clock, Transceivers, Proto-board lay out