BeHāvStudent 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

Schematic

Schematic- USB & Transceiver

Schematic- Real Time Clock

Key FobOriginally 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 CapacityFlash 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

Software Architecture Spec.

Sequence Diagram - Feedback

To hub or not to hub?Hub Advantages• Single station for

devices

Hub Disadvantages• Limited mobility• Higher cost• Limited expansion

Proposed USBConnect the Receiver directly to an external

PC via USB.– Increased Mobility– Less Expensive– Supports any number of devices

USB Port InterfaceAllows 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

Project CostsReal Time Clock $20.00

7 segment LED $15.00

PCB $120.00

MSP430F2270 Sampled

MSP430F2270 Dev Board Provided

Transceiver+Dev board $100.00

USB Interface $40.00

Stripboard $11.00

G13566 Motor $3.00

Voltage Regulator $2.25

Documents $60.00

Other $28.75

Total $400.00

Receiver Unit CostMSP430F2272 $3.00 $3.00

DC Vibrator $1.00 $1.00

Transceiver $28.00 $6.00

7-Segment LED $6.50 $2.00

Real Time Clock $5.00 $5.00

USB Interface $25.00 $7.00

PCB $40.00 $40.00

Voltage Regulator $2.25 $2.25

Total $110.75 $66.25

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

Schedule

TasksMutual Tasks: Documentation, Tech manual, User manualMatt: Transceivers, MSP430 Firmware, and Proto-board lay outJosh: MSP430 Firmware, LED display, BCDNick: Computer interface, USB, MSP430 Firmware, Real Time ClockTerrel: PCB, Transceivers, Proto-board lay outMohamed: PCB, Real time clock, Transceivers, Proto-board lay out

Questions?