chapter 5 input 5. mouse课件

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1、CHAPTER5InputMouseInsideaMouseThemaingoalofanymouseistotranslatethemotionofyourhandintosignalsthatthecomputercanuse.Almostallmicetodaydothetranslationusingfivecomponents:Aballinsidethemousetouchesthedesktopandrollswhenthemousemoves.Theundersideofthemouse'slogicboard:Theexposed

2、portionoftheballtouchesthedesktopTworollersinsidethemousetouchtheball.OneoftherollersisorientedsothatitdetectsmotionintheXdirection,andtheotherisoriented90degreestothefirstrollersoitdetectsmotionintheYdirection.Whentheballrotates,oneorbothoftheserollersrotateaswell.Thefollowing

3、imageshowsthetwowhiterollersonthismouse:TherollersthattouchtheballanddetectXandYmotionTherollerseachconnecttoashaft,andtheshaftspinsadiskwithholesinit.Whenarollerrolls,itsshaftanddiskspin.Thefollowingimageshowsthedisk:typicalopticalencodingdisk:Thisdiskhas36holesarounditsoutere

4、dge.OneithersideofthediskthereisaninfraredLEDandaninfraredsensor.TheholesinthediskbreakthebeamoflightcomingfromtheLEDsothattheinfraredsensorseespulsesoflight.Therateofthepulsingisdirectlyrelatedtothespeedofthemouseandthedistanceittravels.closeupofoneoftheopticalencodersthattrac

5、kmousemotion:ThereisaninfraredLED(clear)ononesideofthediskandaninfraredsensor(red)ontheother.Anon-boardprocessorchipreadsthepulsesfromtheinfraredsensorsandturnsthemintobinarydatathatthecomputercanunderstand.Thechipsendsthebinarydatatothecomputerthroughthemouse'scord.Thelogicsec

6、tionofamouseisdominatedbyanencoderchip,asmallprocessorthatreadsthepulsescomingfromtheinfraredsensorsandturnsthemintobytessenttothecomputer.Youcanalsoseethetwobuttonsthatdetectclicks(oneithersideofthewireconnector).Inthisoptomechanicalarrangement,thediskmovesmechanically,andanop

7、ticalsystemcountspulsesoflight.Onthismouse,theballis21mmindiameter.Therolleris7mmindiameter.Theencodingdiskhas36holes.Soifthemousemoves25.4mm(1inch),theencoderchipdetects41pulsesoflight.YoumighthavenoticedthateachencoderdiskhastwoinfraredLEDsandtwoinfraredsensors,oneoneachsideo

8、fthedisk(sotherearefourLED/sensorpairsinsideamouse).Th