Optical mouse working principle

Optical mouse working principle

Anas Ibrahim,Moeen Ghafoor

GIK institue

Dec 12,2014

Outline

• History and literary study

• Optical mouse.

• Little glance of optics in ball mouse.

• General optical and laser mouse comparison.

• Electronic Components

• Working principle

• Light scattering and LED

• Optical mouse sensor

• Communication IC

• Scroll mechanism

• Click mechanism

• References2GIK institute Anas Ibarhim,Moeen Ghafoor2/11/2015

History and literary study

• Optical mouse was invented in 1980.

• It didn't gained public attention but in 1998

• First wander was Sun micro systems.[5]

• MAX1000 laser mouse entered into market in 2004 by Avogo and Agilient technology.

• VCSEL technology introduced to reduce size.

• Dark field laser sensor introduced in 2009

3GIK institute Anas Ibarhim,Moeen Ghafoor2/11/2015

Optical mouse

• It is device which is used to measure the motion and acceleration of pointer.

• It uses light source instead of ball to judge the motion of the pointer.

• Optical mouse has sub type called laser mouse but they share same working principle.


Little glance of optics in ball mouse

• Ball mouse also posses

led for measuring the

revolution.

• Led light is intercepted

by the wheel.

• Photo detector records

interception and send the signal to processor


General optical and laser mouse comparison

General optical mouse

• Optical mouse uses red, blue green led.

• Optical mouse have three buttons.

• Optical mouse is less sensitive.(units DPI)

• Sensitive towards surface.

• Short battery life

Laser mouse

• Laser mouse uses only infrared led.

• Laser mouse has as many as 12 buttons and can be programmed by user.

• Highly sensitive.

• Able to work on any hard surface

• Low battery life


Electronic Components

1. Led source

2. Lens

3. Mounted camera

4. Scroll mechanism

5. Micro switching

6. USB


Working principle

• Light is focused on the lens.

• It diverged and come to surface after deflection from two palates.

• Photo detector can is used to pick the change in intensity of light at different position.

• Signal is processed and is transferred to the computer.

8GIK institute Anas Ibarhim,Moeen Ghafoor

2/11/2015

Schematic of reflection[2]

Light scattering and LED

• Lens is used to focus the light.

• Led is used which emitter the light

• This can be IR or visible LED


Above lens and led on left

Engineering garage.com


Light scattering and LED(cont’d)

• Laser of very small power is

used.

• IR laser is used IR laser

mouse[2]


Bottom side of laser mouse



Optical mouse sensor

• IC shown in the figure works

on the navigation technology

• IC above is DSP chip which

acquits image and process it.

• In this way it determines thedirection and distance.

• Photodiode/camera is CMOS

sensor uses house lens to

capture 1500-6000 images[4].


Camera embedded chip

Communication IC

• This IC uses I2C protocol

for interfacing[2]

• USB transceiver IC

• It works as voltage

regulator[3]


Communication IC


Communication IC(cont’d)

• Communication IC composed of Digital image processing algorithms

• Can do processing at the rate 18MIPS.

• Above pattern move to south east on opposite motion of mouse.


DIP schematic


Scroll mechanism

• When the wheel is rotated

the potentiometer also

rotate.

• Change in the resistance

corresponds to the revolutions


Scroll mechanism



Click mechanism

• Red part is used for clicking

purpose.

• When a button is clicked,

a flexible metal plate is

pressed which shorts the

two points of the circuit that

detects the mouse click.




Conclusion and future

• New emerging technologies are being utilized in the working mechanism of optical mouse and to make its use easy and comfortable.

• We can expect its prices and size will be reduced in future for new ways of circuit design.

2/11/2015GIK institute Anas Ibarhim,Moeen

Ghafoor16

Reference

1. en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laser

2. explainthatstuff.com/computermouse.html

3. thescienceera.wordpress.com/2014/08/13/optical-mouse-work/

4. engineersgarage.com/insight/how-optical-mouse-works?page=1-8

5. engineersgarage.com/contribution/difference-between-optical-mouse-and-laser-mouse


Ghafoor17

http://en.wikipedia.org/wiki/Vertical-cavity_surface-emitting_laser

http://www.explainthatstuff.com/computermouse.html

https://thescienceera.wordpress.com/2014/08/13/optical-mouse-work/

Questions


Ghafoor18

Optical mouse working principle

Engineering

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