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Multidisciplinary Engineering Senior
Design
6510 Interface Project
Preliminary Design Review
11/19/05
Project Participants
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Sponsor: Mr. David Perlman
Coordinator: Professor George Slack
Team Members: Eric Bohannon (CE),
Michael Winslow (EE), Scott Urban (ID)
Project Mission
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Create a cost effective card reader that
wirelessly transmits the data to a
listening host computer to perform a
computer instruction
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Platform independent
Audience of 10 to adult
Card containing bar code created on credit
card size piece of cardboard
Feasibility
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Project mission is attainable
Innovation
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Creative way to convert cardboard ink to electronic signal
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Photo-Diode
Creative way to design “card reader”
Interfacing
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Keeping bits from bar code stored
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PIC
Wireless Communication between host computer and card
reader
Customer Requirements
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Entire product is low cost
Card reader is compact
Card reader is battery powered
Card produced on inkjet or laser printer
Customer Requirements
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Card produced on cardboard
Card Dimensions (credit card)
Platform independent
Wireless transmission
End software has media capability
Block Diagram
Bar code
reading
circuitry
Card
Reader
Power
Supply
Wireless
transmission
circuitry
Card
containing bar
code
Wireless
Receiver
circuitry
Host PC
reception
Host PC
software
(media app)
Core Design Modules
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Card Reader (physical structure,
dimensions, look and feel)
Card containing bar code
Power supply
Bar code reading circuitry
Core Design Modules
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Wireless transmission circuitry
Wireless receiver circuitry
Host PC wireless reception
Host PC end software
Card Design
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Credit Card Size
Card Stock
Black Bar = “1”
White Bar =“0”
Card Reader
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Self Contained (power supply, bar code
circuitry, wireless transmission circuitry,
and card holder)
Slot for obvious insertion of card
Withstand falling
Reader Design
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Aesthetics (board/party game)
Appeal to young teenagers without
distancing adult market (target: 10-up)
Reader Design
Power Supply
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Standard (Duracell/Energizer) 9V
batteries
LM2937 5V linear regulator
Save Power
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Sleep Mode (PIC)
Disable Wireless Transmission
Low Battery Detect
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Low Battery Warning
Voltage Divider with Comparator
Bar Code Reading Circuitry
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Eight detectors will be used to detect
the black (no light) and white (light)
lines on the card.
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Comparators
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CMOS Levels
IS489 Light Detector
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Eight IS489 devices will read the data
bits off the card.
Light
No
Light
IS489 Light
Detector
IS489 Light
Detector
0 volt output
To PIC
5 volt output
To PIC
PIC16F627 Microcontroller
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Controls photo-detectors and wireless
circuitry
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SLEEP mode
16 Input/Output pins
RISC CPU, each instruction takes 1us @ 4
MHz (except program branches)
Power Up
Initialize Registers
and I/O pins
Wake up
Interrupt (card
entered)
SLEEP mode
Read Data off Card
TX Data to IR
Transceiver
Wait for “OK” signal
coming back from
computer
Check Low
Battery Pin
Flash LED
to Indicate
Problem
Yes
Signal
Received
No
Signal not
Received
Wireless Circuitry
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Agilent HSDL-3000 IR Transceiver
One at card reader and another at
computer end.
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Typical link distance > 1.5 m
Low shutdown current (10 nA typical)
Agilent HSDL-3000
USB Interface
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FTDI FT232BM
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Receives data from IR transceiver and
sends it to the computer via USB port.
Virtual com port drivers available
DLP-TXRX
End Software
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Java program listening to USB
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Receive each bar code from USB
Filter “noise”
Execute instruction
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Virus scan
Mail check
Special Media options
Query USB
Thread
Bar Code
Received?
No
Yes
Update
Spreadsheet
Media file?
User Request
Thread
Yes, user
queue?
Handle User
Requests
Yes, place in
queue
Create
Card
Change Bar
Code
If user queue,
Check Media
Availability
Maximize
Window
If free, execute
next media in
queue
No, Execute
File
Physical Level Realization
PIC16F627A
Card
Reader
(plastic)
Battery
(Duracell)
IR transceiver
IR transceiver
PC/ MAC/
Laptop
USB
connection
5V USB
power
PIC16F627A
Human
User
Card
Reader
User Scan
(power
enabled)
Card entry
recognition
Cards
Black = 1
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End Result
Printer
(inkjet or
laser)
Photodetector
Reflection
White = 0
Amplify,
Digitize
signals
PIC bit
reception
IR
reception
IR
transmission
USB
Communica
tion
Java
software
bit
reception
Media
Application
Update
Interface
Enter
Waiting
Queue
PIC bit
recognition
Cost Assessment
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Power Supply ~ $4
Photo-Detector Circuit ~ $7
Microcontroller ~ $5
IR Transceivers ~ $7
USB Interface ~ $7
Total ~ $30
Testing
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Battery Life
Card Reader Dimensions
Card Size Dimensions
Bar code dimensions
Distance between photo-detectors
Testing
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Wireless transmission error rate
User error
Photo-detection error
Wireless distance
Mac/Windows capability
Technical Concerns:
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Power Saving (ability to keep card
reader off when idle)
Wireless signal distance (how far away
will card reader be from computer)
Photo-Detector saturation levels (how
differently will black ink and a white
background saturate a transistor)
Questions ?