Senior Design II: IKE

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Senior Design II IKE
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Infrared Keyless Entry

Final Presentation Senior Design II November
27, 2001 Mississippi State University Department
of Electrical and Computer Engineering
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Abstract

• Design an interface to allow entry without keys.
• Radio Frequency Keyless Entry (RFKE) does not
  provide flexible interaction between automobiles
  and external communication devices.
• Infrared technology integrated with keyless entry
  will provide alternate access to automobile.
• Devices such as laptops and palm pilots with
  infrared ports will be able to access the system.

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Motivation

• Allow alternate entry to automobile without keys.
• Give flexibility to access multiple components of
  car.
• Ability to program car components with IrDA
  software.

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Infrared Keyless Entry System
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Team
Adria Jones, Team Leader
Ray Smith
Kenny Reynolds
Dr. Ray Winton,Advisor
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Design Task Breakdown

• Kenny Reynolds
• Digital Signal Encoding / Decoding
• Micro-controller Interface
• Adria Jones
• Transmitter / Receiver Amplification
  Transmission
• Ray Smith
• IrDA Implementation

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Key Components
Optical Signal Receiver
Handheld Ir Receiver
Decode
Amplification
Micro-Controller
Specified Function
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Design Requirements
 1. Functionality The receiver unit will be able
to receive and decode encrypted signals sent from
a transmission device via infrared media. After
proper decryption, the unit will send a signal to
unlock the doors and/or perform some other
user-desired operation on another device of the
vehicle. 2. Unique Signal Keying The
transmitter will send unique encrypted infrared
signals to the receiver. The receiver unit will
be able to decrypt codes sent by the infrared
remote. The receiver will also be IrDA-1.1
compliant to be able to receive instructions from
a third party device, such as a laptop computer
or PDA. 3. Power Power to the receiver unit
will be delivered from the vehicle's battery.
The system will operate from 10 to 15 Volts DC
and consume no more than 100 mA of current. The
transmitting unit will operate on a 12V battery
and consume no more than 100 mA of current when
in operation.
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Design Requirements
4. Physical Attributes The receiver unit
will be designed to be easily installed within a
properly equipped vehicle. The transmitter will
have simple buttons for the specified function of
the keyless entry system specified by the
user.  5. Affordability Components for both the
transmitter and receiver units will not exceed
35.
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Serial Encoding / Decoding ICs

• Holtek HT-640 serial encoder and HT-648L
  decoder.
• Provide 10 data address lines and 8 control
  lines. (High, Low, Open)
• Built-in RC Oscillator allows for multiple
  transmission frequencies (0.15 kHz to 2.6 kHz).
• Codes supplied by PLD (PAL16L8)

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Serial Encoding

• 10 control lines, 8 data lines
• Can be tied High, Low, or left open.
• 318 possible serial combinations.
• Code Scanning? At 10 scans/sec -gt 1.23 years
• Example Coding from PIC (f 100 kHz)
• A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 D1 D2
  D3 D4 D5 D6 D7 D8
• 0 1 0 1 1 0 1 0 0
  1 1 1 0 0 0 0 0
  1 1
• 0 1 0 1 1 0 1 0 0
  1 1 1 0 0 0 1 1
  0 0

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Transmitter Circuit
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Transmitter
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Simulation/Results

Power Constraint 100 mA Actual 52mA Peak
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Receiver Circuit
IrDA I/O
Output
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Receiver Circuit
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Finished Product
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I/O Signals
Xmitter
Receiver
I/O signals at close range (1 foot).
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I/O Signals
Xmitter
Receiver
I/O signals at close range (1 foot).
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I/O Signals at Distance
Xmitter
Receiver
I/O word signals at distance (15 feet).
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I/O Signals at Distance
Xmitter
Receiver
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Ir Problems at Distance

• Ir input signals are shortened.
• HT648L Decoder chip requires bits slightly longer
  
• to match the operating transmission frequency
• of the system.
• Possible solution Tuning the attenuator box?

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IrDA Access Program

Software interfaces through the PC into the
PC/PDAs IrDA hardware level.
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Our Problems With IrDA

• Software -
• PC Interfacing Hardware Layer of IrDA protocol
• Microprocessor Code
• Cant pack enough decryption software into our
• Microprocessor to thwart random code scanners.
• Hardware
• Ambient daylight Ir causes severe transmission
• problems with IrDA.

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Cost
DESIGN COMPONENTS COST
Serial Encoder 2.49
Serial Decoder 2.49
Microprocessor PIC 5.95
IR X-mitter LEDs 2 0.30
IR Receiver LEDs 2 0.30
IrDA Transceiver 3.10
Quad OpAmp 1.29
SPST Relays 2.18
Resistors Capacitors 1.00
Packaging 6.00
PCB Fabrication 3.00
Battery (12V Alkaline) 0.89
TOTAL DESIGN COST 28.99
Design Requirement 35
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Demonstration
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MetRequirements

Functionality Unique Signal
Keying Power Physical Attributes Affordability

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Future Work

• Improve the Signal Range!
• Finish Debugging IrDA Software
• Package Logic Module into a Smaller Box

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QUESTIONS?
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References
1 "Technical Summary of "IrDA DATA" and "IrDA
CONTROL", http//www.irda.org/standards/standard
s.asp, Infrared Data Association, Walnut Creek,
California, 2000.   2 How Infrared Motion
Detector Components Work, http//glolab.com/pirpa
rts/infrared.html, Glolab Corporation, 2000
  3 Weiner, Seymour. Infrared Radiation,
Encyclopedia Americana, Vol. 15 . p.169.
Grolier Inc., 1994.   4 Knutson, Charles D.
Infrared Data Communications with IrDA. IrDA
Test and Interoperability Committee. Corvallis,
Oregon, 1998.
Senior Design II IKE