GUIDED LASER MOUSE
ECE 445: Senior Design Spring 2007
Samir Desai Howard Luo James Lin
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
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
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
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
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.
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
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%
555 Generated Waveform
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
Clicker Schematic
Receiver Schematic
Printed Circuit Boards
Once final boards were built and successfully tested, we designed PCBs Helped with size configuration Provided more suitable casing options
PCB issues
The PCBs for the clicker and the receiver were never successfully tested 555 timer Max232 Hardwiring Floating voltages
PCB pictures: Clicker
PCB pictures: Receiver
Casing Pictures: Clicker
Casing Pictures: Clicker continued
Casing Pictures: Receiver
Casing Pictures: Receiver continued
Testing and Plots
Capacitive button:
Testing and Plots continued
Transmitter to Receiver 2400 Hz:
Testing and Plots continued
Transmitter to DB9 input at 2400 Hz and 20 feet:
Future Improvements
Drag and Drop feature Miniaturization USB implementation
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
Block Diagram of Integration
r e a d f r o m s e r ia l
in t e p r r e t " i " s a n d " j " s
l a s e r p o i n t e r p o s it io n
r e t u r n s P o in t c la s s v a r
s e t u p m o u s e c li c k i n p u t
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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
Serial port loopback
Serial port pin diagram
RS232 Test Program
RS232 Test Program
RS232 Test Program
RS232 Test Program
Behind the GUI
Serial Port Settings
Baud Rate: 2400 Data Bits: 7 Stop Bit: 1 Parity Bit: none
Reading from the Receiver
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
Process for reading COM port
Open COM port On data received, read in data from COM port buffer Interpret data Close COM port
GUI of COM port tester
Reading from Image Processor
clickLocation = detector.point;
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;
Testing Mouse Control
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
Image Processing
Logitech QuickCam Fusion Microsoft DirectShow 320x240 BitMap ~8-10 fps Applied a red filter to camera lens
Image Processing
Image Processing
Every 5 pixels of BitMap is checked
(299 Re d ) + (587 Green) + (114 Blue) Brightness = 1000
Brightness = (299 Re d ) + (587 Green) ...