Intruder detection

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Intruder detection

• Adriana Ogasawara Joshua Mahaz

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Problem Statement

• Reside in an apartment with a malfunctioning door
  chime. The randomness of the failure prevents
  cheap diagnosis and repair.
• Create a device that can be placed in a homes
  entry way and notify the home owner of any
  anomalies witnessed.
• Gain experience in developing software for
  low-cost 8-bit RISC microcontrollers and RF
  transmitter receiver modules

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Specifications

• Affordable
• Package price lt 100
• Two Module Device
• Remote Sensor
• Base Station
• Wireless
• Easily relocated
• Low interference

• Future Expandability
• PC communication
• User Interface (Base)
• LCD display
• Audible alert
• Multiple alert modes

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Multiple Alert Modes
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System Diagram
Remote Sensor Base Station
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Cost
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Resources

• Hardware
• Sparkfun.com
• Digikey.com
• Parallax.com
• Software Tutorials
• AVRfreaks.net
• Sparkfun.com
• Atmel.com

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Resources

• IDE
• WinAVR
• AVR Studio
• Programming Interface
• Parallel (Not compatible with Vista)
• AVRdude

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Parallel Port Interface
Parallel Port
Notes Resistors protect PC parallel port from
overvoltage Unless reset line is switched
programming port will have to be removed to take
the AVR out of reprogramming mode
AVR Microcontroller
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WinAVR

• http//winavr.sourceforge.net/
• Set of open source software development tools for
  the Atmel AVR series of RISC microprocessors for
  Windows OS
• Command line compiler
• Compiler library
• Assembler
• Programming interface
• De-bugger
• Editor

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ATMega168

• 4.93 (Sparkfun)
• 28 pin DIP
• 23 I/O lines
• 16K of program space
• Hardware USART
• Runs up to 20MHz

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RF Link

• 13.95 (Sparkfun)
• Receiver good for data rates up to 2400bps
• Advertised 500 ft range in open space
• Receiver is operated at 5V and the transmitter
  operates from 2-12V
• Low interference at 315 Mhz
• Small and lightweight
• TX RX Pair

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LCD

• 15.95 (Sparkfun)
• 16 character by 2 line display
• Utilizes HD44780 parallel interface chipset
• Uses 11 or 7 general I/O pins to interface

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Passive Infrared Sensor

• 9.95 (Parallax.com)
• Measures infrared levels of surrounding objects
• Detects motion up to 20 feet away
• Only tripped after large changes
• Simple 3-pin connection
• Single bit output
• Small size

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User Interface
Power Switch Alert Mode
LCD Contrast
Spare Momentary
Programming Port Spare I/O
Spare Switch
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Button Interface
Microcontroller Includes internal Pull-Up
Resistor
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System Layout
Start-up Routines
Main System Loop
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Initialize System
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Check Configuration
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Sensor Configuration
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Base Configuration
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Base Configuration
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Configuration Independent
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Milestones
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Difficulties

• Parallel Programming Vista
• Vista does not allow the use of the parallel port
  for programming AVR microcontrollers
• Parallel Programming Reset Pin
• Unplug the programming cable after downloading
• Fried Hardware
• LCD 2 M/C
• Wireless Communication
• Everything

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Wireless Problems

• Lack of synching
• Load balancing
• Range
• No antenna
• Enclosure

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Synching Problem

• Snooping the wireless RX line
• Alternating sets of random ascii characters
• The TX message was simplified to 8 bits of
  toggling between high/low
• Resulting output was one of two characters U or
  ?
• Verified synchronization problem
• RX module was unable reliably receive complex
  serial data

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Load Balancing

• Cheap RF modules have a tendency of becoming
  saturated
• Excess of either high or low will increase the
  possibility of erroneous data.
• Load Balancing Algorithm
• 1 is represented by a rising edge
• 0 is represented by a falling edge
• Balanced Alert Message
• 0b01010101

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Range

• Communication only reliable at close range with
  no antennas and in enclosures
• External antenna
• Base Station improved performance
• Remote Sensor crippling power draw
• Cut away a portion of enclosure
• Ranges greater then 10ft or with obstructions did
  not have solid communication

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Range

• Kept the simple sequence of 10101010 for a
  sensor trigger
• Receiver compares current data in buffer to
  10101010 or 01010101 either will result in user
  alerting.
• To reduce noise on the line from causing an alert
  numerous trips need to occur in a windowed time
  frame
• Ensures only valid trips set of alarm

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Lessons Learned

• Always buy the development board
• 30 completely worth avoiding hours of tedious
  low level tweaking
• Pays for itself in avoided fried hardware
• Cheap wireless
• Get what you pay for

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Future Work

• Resolve antenna issue with remote sensor
• Move to a transceiver instead of
  transmitter/receiver pair
• Improved wireless communication
• Two way communication with reduced foot print
• Multiple remote sensors
• PCB

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• Demos

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• Demos

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• Demos

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http//www.mahaz.com/ucf/EEL6883/EEL6883.html

• Demos

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Links

• Project Files
• http//www.mahaz.com/
• References
• http//www.captain.at/electronics/atmel-programmer
  /
• http//www.instructables.com/id/Ghetto-Programming
  3a-Getting-started-with-AVR-micro/
• http//www.micahcarrick.com/05-15-2006/avr-tutoria
  l-switch-debounce.html
• http//www.sparkfun.com/commerce/present.php?pBEE
  -1-PowerSupply

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QUESTIONS?

• Adriana Ogasawara Joshua Mahaz