LASER GUIDED MOUSE

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LASER GUIDED MOUSE

• ECE 445 Senior Design
• Spring 2007
• Samir Desai
• Howard Luo
• James Lin

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Project Description

• Through the combination of a standard laser
  pointer and a clicking device that we designed,
  we have revolutionized the presentation industry
  by introducing a new freedom of movement while
  maintaining control of the computer wireless and
  effortlessly

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Project Sub-units

• This project was divided into three main
  sub-units
• Device design and fabrication
• System integration and driver manipulation
• Image acquisition and analysis

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Device Circuit Design

• Goals of the Clicking Device
• Wireless
• Simple Logic
• Low Power Consumption
• Configurable size
• No lag time
• Very little noise
• Transmission speed that allows rapid double
  clicking

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Design Basics

• Two capacitive push buttons send parallel signals
  that represent the Left and Right mouse clicks
• Parallel signals are encoded into a serial signal
  using an 8 bit shift register. The shift register
  provides a start and stop code that enclose the
  LR signals 010LR010

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Design Basics Continued

• Shift Register outputs serial signal to a
  Transmitter which then wireless sends the signal
  to a Receiver on a different board.
• Receiver takes the signal and sends it to a
  Max232 which converts the voltages into values
  the serial port will recognize and transfers them
  via DB9 and RS232 cable to the com port.

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555 Timer

• Shift register needed a clock frequency that
  would be recognized by comport and be fast enough
  to allow a rapid double click.
• We chose 2400 bits per second (Hz)
• LM 555 Timer allowed us to generate a clock very
  near this frequency

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555 Timer continued
Using two resisters of value 1600 Ohms and 2000
Ohms and two capacitors of value .1uF and .01uF,
we generated a clock signal of 2576 Hz with a
duty cycle 64.3
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555 Generated Waveform
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Design issues and solutions

• After the basic design was completed, there were
  some problematic issues that needed fixing
• Too much noise
• Power source regulation
• Square wave generation

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Clicker Schematic
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Receiver Schematic
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Printed Circuit Boards

• Once final boards were built and successfully
  tested, we designed PCBs
• Helped with size configuration
• Provided more suitable casing options

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PCB issues

• The PCBs for the clicker and the receiver were
  never successfully tested
• 555 timer
• Max232
• Hardwiring
• Floating voltages

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PCB pictures Clicker
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PCB pictures Receiver
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Casing Pictures Clicker
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Casing Pictures Clicker continued
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Casing Pictures Receiver
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Casing Pictures Receiver continued
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Testing and Plots

• Capacitive button

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Testing and Plots continued

• Transmitter to Receiver 2400 Hz

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Testing and Plots continued

• Transmitter to DB9 input at 2400 Hz and 20 feet

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Future Improvements

• Drag and Drop feature
• Miniaturization
• USB implementation

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System Integration

• Serial data read into COM port and analyzed
• Relative location of laser pointer acquired from
  image processing
• Integration of these two factors followed by
  mouse driver manipulation

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Block Diagram of Integration
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Serial Port Test HowTo

• Hardware Serial loop back
• Software Reads in data from the serial port and
  interprets data as Left or Right click

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Serial port loopback

• Serial port pin diagram

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RS232 Test Program
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RS232 Test Program
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RS232 Test Program
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RS232 Test Program
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Behind the GUI

• Serial Port Settings
• Baud Rate 2400
• Data Bits 7
• Stop Bit 1
• Parity Bit none

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Reading from the Receiver
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SerialPort Class in .Net Framework

• Close Closes the port connection and sets the
  IsOpen property to false
• Open Opens a new serial port connection
• ReadExisting Reads all immediately available
  bytes, based on the encoding, in both the stream
  and the input buffer of the SerialPort object.
• Write Writes data to the serial port output
  buffer

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Process for reading COM port

• Open COM port
• On data received, read in data from COM port
  buffer
• Interpret data
• Close COM port

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GUI of COM port tester
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Reading from Image Processor

• clickLocation detector.point

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Mouse control HowTo

• Use import method SendInput of the user32.dll
  library
• DllImport the User32.dll
• Remember to add the library
• using System.Runtime.InteropServices

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Testing Mouse Control
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Process for Mouse Control

• Set Text Left / Right
• Set the cursor to memorized location
• Set up the INPUT structure
• Fill it for mouse down and send the input
• Fill it for mouse up and send the input

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Image Processing

• Logitech QuickCam Fusion
• Microsoft DirectShow
• 320x240 BitMap
• 8-10 fps
• Applied a red filter to camera lens

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Image Processing
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Image Processing

• Every 5 pixels of BitMap is checked
• Finds brightest spot in picture

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GUI
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Calibration

• Software automatically determines the users
  screen resolution
• Define four corners using laser pointer and
  buttons on GUI
• Use corners to determine upper lower, left, and
  right bounds
• Calculate XFactor and YFactor
• Convert BitMap location to screen (x, y)

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Calibration Marks
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Calibration
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Calibration

• XFactor and YFactor 3.5 4.5
• Therefore approximately every 20 pixels on the
  screen is clickable
• point new Point(ScreenX, ScreenY)

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Calibration
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Future Improvements

• Faster scanning for more precision
• Automatic detection of background brightness
• Compensation for slanted projected screen
  (Keystone)

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Ethical Considerations

• Dont point lasers in peoples eyes!

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Special Thanks to

• Ethan Miller ECE 445 Teaching Assistant
• Scott McDonald Machine shop supervisor
• Wally Smith ECE parts shop inventory staff
• Mark Smart ECE parts shop PCB fabrication
• Thank you all for your time and patience. We
  could not have done it without you!

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Questions

• Any questions?