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Input Devices
- March 2009:
Input devices are too often taken for granted by users. But
if the idea is as much to put data in as to get data out,
then the input devices we use are critical. Elsewhere in
this document I've given some information about the care and
use of input devices; this section focuses more on exactly
what makes these devices tick, and what you need to know
about their inner ticking.
The most ubiquitous of input devices, keyboards tell the
BIOS and ultimately the CPU which keystrokes you've entered.
Keyboards use two methods to detect and report keystrokes:
contact, or switch, and capacitive. Contact
types are older, using a mechanical switch to close a
circuit with each keystroke.
Capacitive keyboards do away with the mechanical switch in
favor of reliance on a change in capacitance (stored energy
charges) to read the stroke. Contact keyboards come in
several varieties, the most popular with spring-loaded keys,
but also appearing with "rubber domes" and "membranes," both
of which tend to survive longer in dusty, dirty
environments. Your preference for audible and tactile
feedback may determine your preferences here. Capacitance
keyboards tend to last longer than contact keyboards, but
cost a bit more. Also check out the new wireless keyboards.
Win ME, 2K, and XP owners have an "Onscreen Keyboard." This
little goodie gives you a keyboard that appears on your
screen and can be accessed through a mouse or other
input/pointing device. To access the On-Screen Keyboard,
from the Start menu select Programs, Accessories,
Accessibility, On-Screen Keyboard. Then open the application
that you wish to use with the On-Screen Keyboard. Select the
keys on the On-Screen Keyboard to enter characters into the
active application. Optionally, select Keyboard to choose
the keyboard appearance and layout options as necessary.
Optionally, select Settings, Typing Mode to adjust the
typing method. Select the typing mode as appropriate for
your needs. If you select hover mode, choose the hover time
interval before characters are selected. Click the OK
button. To close the OSK, just click the Close button. The
idea is to make keyboard access easier for disabled users,
but laptop and tablet PC users who dump coffee on their
keyboards may find this a useful, if short-term, workaround.
Cleaning your keyboard is a necessity. Here's how. First,
unplug your keyboard, hold it upside down over a sheet of
newspaper, and tap it gently to remove loose crud. Next,
take it outside and use a can of compressed air to blow out
the dirt between the keys. Turn it over and tap out the
loose crud again. Now, make a solution of dishwashing liquid
and water, and use a dampened cloth to clean the key
surfaces. Wipe dry. You can use the dusting attachment (the
brush) on your vacuum cleaner to go over the keyboard one
more time. Still dirty? Sometimes they get filthy,
especially if you, like me, have teenagers who like to eat
sloppy food with one hand and type with the other. Here are
some tips strictly for filthy keyboards that use
membrane-type keys (the mechanical keyboards have
spring-loaded keys that make a distinctive clicking sound
when they are pressed). Pop off the keys one by one -- you
will probably want to use a digital camera or copy machine
to make a copy of the key layout so you get the keys back on
in their proper places. Remove the smaller keys with a small
screwdriver, and be gentle. Don't remove the bigger keys
such as Enter and the spacebar. Use compressed air and a
damp cloth as above to remove the smutch. Really tough crud
can be removed with cotton swabs dampened with isopropyl
alcohol. Use the compressed air again. When everything is
dry, replace the keys. Make sure everything works properly
when you reattach the keyboard.
Actually, a mouse is just one type of pointer device
used by various machines to input data. It's by far the most
popular, first developed by the Xerox PARC team in the
1970s, introduced to the PC market by Apple for the
Macintosh in 1984 (in the notorious one-button version) and
carrying on strongly ever since.
Different mice are used for different machines: Mac mice
depend on a single button, UNIX mice use three, and most PC
mice use two buttons, with some manufacturers assigning
custom functions to a third button and many sporting a
central "wheel" for scrolling. Today's mice no longer use
the serial port or a bus card to connect, preferring to
connect either through a USB port or directly to the
motherboard. Windows has a standard mouse driver program
inbuilt to drive a mouse, but that generic driver is
replaced by whatever driver comes with the mouse currently
installed. That's why you can't just plug in an alien mouse
and blast away; each mouse uses a specific driver, usually
provided on a floppy or CD. Trackballs are very similar to
mice, except they roll inside a socket instead of freely on
a mouse pad. Trackballs are even more susceptible to dirt
and gunk than a mouse, which can go down within hours in a
dirty environment. Track points and touch pads are other
versions of pointing devices similar to trackballs, and are
even less popular than the trackball. Mice are by far the
preferred pointing device currently available. New on the
market: wireless mice, which replaces wires with optical
interfaces. Really new on the market: much smaller mice that
are designed to work with laptop and notebook devices.
You can configure your mouse's functions by going through
the Control Panel applet (in XP, the Mouse tab is under
Printers and other hardware). Note: different mouse
software gives users different options. You can control the
speed of your mouse's sensitivity to double-clicking, or
even set the mouse to open items with a single click. If you
have something called "Click Lock," you can have the mouse
click drag by simply holding down the button for a moment or
two, and release the dragged item with another click. You
can control the rate and sensitivity of your mouse's
scrolling; if you have a wheel mouse but you're missing the
"Wheel" tab or its equivalent, you may need to download a
newer driver from your mouse maker's Web site. Pressing the
wheel on some mice may activate "panning" or a variant of
the "AutoScroll" feature. You can adjust the speed at which
your cursor moves in response to the mouse. You can also
make your cursor instantly appear over the default option
when you open a dialog box, though this option can make you
hunt for your cursor over and over again. Win ME labels this
option "Smart Move," while 2K and XP call it "Snap To" or
"Snap To Default." You can have the cursor disappear when it
isn't in use, or not. You can have the Ctrl key, or another
key, locate the cursor with a visual effect when pressed.
You can enable or disable pointer trails that display behind
your mouse (especially good on small screens like
notebooks). You can have the mouse controlled by the
keyboard if you really hate using the mouse, by enabling an
option called "MouseKeys." And of course, you can change the
various cursors as you like -- if you really want to get
fancy, there are plenty of animated cursors and fun things
available on the Web to spice up your cursors.
How to use the mouse in old DOS games? Win 98 has a "Mouse_in_DOS"
command that can be inserted into the SYS.INI file, but that
doesn't help the rest of us. There are several ways to
stroke this particular cat. Your system may include a
MOUSE.EXE or MOUSE.COM file -- essentially an old mouse
driver utility for DOS. Or, you can grab a mouse driver for
free from most download sites online, including
dos.li5.org/downloads/drv.htm. The more-or-less
universal Microsoft mouse driver is here:
downloads.zdnet.co.uk/downloads/detail/1002-2110-900552.html.
Most other mouse vendors' sites also have brand-specific
drivers, if you need them. Warning: a mouse connected to a
mouse port -- or even an old serial mouse connected to a
comm. port -- will work fine in DOS with the right driver.
But USB devices generally don't work in DOS, and that
includes USB mice. Lots of sites offer how-to info on
installing and using a mouse driver.
Here's a good chunk of info on the optical mouse, adapted
from
Vince
Underwood's piece on the subject in his November
2002 newsletter. Thanks, Vince!
Developed by Agilent Technologies and introduced to the
world in late 1999, optical mouse sensor technology works by
taking thousands of digital pictures per second with a
resolution of up to 800count/in to determine the movement of
the on-screen cursor. These individual images are then sent
to the digital signal processor (DSP), which compares each
picture with the last to detect movement. In doing so, the
processor executes 18 million instructions per second. The
mouse then outputs the signal to the computer via a USB or
PS/2 port, and the software handles the rest of the work.
What this translates to is a more accurate representation of
the mouse's movements and a more accurate implementation of
what the user wants to do with the mouse. Gamers will reap
the benefits of these mice as they are very quick and
accurate in their aiming ability. Optical mice avoid the
need for a mouse pad and offer more precise pointing and
movement than mechanical mice, as long as you don't put the
mouse on a surface that reflects or shines. The mouse needs
to report back to the processor with comparison images, so
placing it on a reflective surface or even a glass surface
will produce the exact same images when moved across this
surface. And since optical mice have no ball or cavity, no
cleaning is necessary, making them more reliable and longer
lasting. They provide automatic power conservation during
periods when the mouse is not moved, and controlled drive
for the LED light source. Optical mice operate on a single
power supply and feature on-chip LED drive and power
conservation mode during times of no movement.
If IBM had included a gaming port with their PC-XT and -AT
machines, it's highly possible that machines today would
come with joysticks (or "gaming devices") as standard
equipment. But IBM was snooty and, besides ceding a large
chunk of its market to the Commodore 64 as a result,
set PC gaming back a generation. Apparently joysticks, like
color graphics cards and sound cards, didn't fit with IBM's
button-down world paradigm. God knows it didn't take
companies like Creative Labs, Hercules, Matrox, and Roland
much time to leap into the void, but that's the reason why
'80s IBM users had to spend so much time cursing over
compatible sound and graphics cards. (Ironically, the PC 98
standards called for game adapters on all "Entertainment
PCs," so those are grudgingly becoming a standard.) The most
common type of gaming device is the joystick, in all its
many varieties. Newer offerings are purely digital,
eschewing the mechanics of the old joystick for faster, more
precise digital throughput; even better, most digital sticks
don't require recalibration. If you have a joystick
connected to your PC, you should show a Joystick icon in the
Control Panel. Double-click this and you'll see a chance to
test the stick. Click the Test button. Then move the stick
to see the small plus sign move in the position test area.
Next, press the buttons and see if the Button 1 and Button 2
areas highlight. This testing only applies to the stick's
use in Windows games, not DOS games. Note: Win ME gives you
a Gaming Options applet in Control Panel that makes it easy
to set up joysticks, flight sticks, steering wheels, and
other game input devices.
Touch screens, light pens, golf simulators, scanners,
digital cameras, and microphones are only some of the other
input devices out there. The idea is the same, though: to
render the human output into a form the PC can understand.
The KVM switch is a new kind of device on the market that
lets you switch back and forth from one computer to another
while still using the same keyboard, video, and mouse input
devices. You can use a KVM switch to alternate between
laptop and desktop machines, between multiple desktops, or
whatever, saving lots of cash and desktop space. Just
remember that the KVM switch needs to support the highest
video resolution of all the machines you intend to use, and
that some KVM switches degrade images at high performance,
so shop around and do your homework before buying.
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