We talk about the joy of mechanical
keyboards and what you need to get a good one
A typical review that I write here contains
around 3,000 characters (more if you include spaces), and on average I write
about 500 pages a year. That works out at around a quarter of a million words
and at least 1.5 million key presses. Factor in other publications and keyboard
use and we’re probably closer to 450,000 words and three million key presses,
which explains why after about six months of typical use the vowel key tops on
my keyboards are polished to the point that they’re all but unreadable.
The
Cherry MX Black key switch. Generally considered to be one of the best options
for those who are gamers rather than typists
However, it’s not just the keyboard that
takes a beating on my desk: what’s happening to my fingers? That’s a concern,
which is why I’ve taken the step of finding out what the best keyboards are and
what the technology behind them is.
Why So Mechanical?
I’ve noticed that lots of laptop makers
these days don’t care for mechanical keyboards, usually because they cost more,
but also the key travel on them makes the machine thicker. Some of these
designs, like the ones that Microsoft has offered on the Surface, use two
electrical contacts separated by a stiff membrane, which the pressure of your
finger brings together to complete the circuit.
The problem with this method is that there
is no obvious physical feedback when the key transitions between not pressed
and pressed, so to make sure you register a press you’re inclined to use more
force than is really needed.
That can cause damage to both the tendons
in the fingers, muscles and also the joints, which can eventually lead to
long-term damage and discomfort.
Cherry
Black MX Pink
The best keyboards, and the ones that allow
you to type rapidly and accurately, are mechanical ones, because they register
the key press before they’re fully depressed, which reduces the wear on you,
importantly.
The worst possible keyboards for comfort
are those on the screens of tablets, where you are effectively smashing the end
of your finger into a hard surface repeatedly. Those that input more than short
messages on their tablet need to seriously consider buying a Bluetooth keyboard
before they irreparably damage themselves.
Important Keyboard Knowledge
If advice on keyboards was as simple as
‘get a mechanical one’, then this would be a short article that wouldn’t be
remotely interesting. However, there are lots of variations within the making
of keyboards that can dictate if the design is right or not for you. For
starters, should you go for a USB or PS/2 type?
Cherry
G80-3000
Since it came along, USB has become the
standard for keyboards, as systems come with multiple USB ports and you can
have a desktop hub that makes your cabling much less complicated. Older systems
use the PS/2 connector, which is older than the hills, so which is best? PS/2,
amazingly.
The way that USB works means that the
system must poll the keyboard to find out if a key has been pressed and,
depending how busy the USB bus is, those polling actions might feasibly miss a
press. There is another USB mode which is interrupt driven, but the expense of
providing this means it’s never used on keyboards.
Alternatively, PS/2 connection is
inherently interrupt driven, so when the key is pressed a small CPU in the
keyboard sends a message to the main CPU to the effect that key ‘X’ was
pressed. That allows them to exhibit something called NKRO (N-Key Rollover). A
USB keyboard can only be polled for a set number of simultaneous keys being
pressed and any more are ignored. Most USB keyboards will only see four
different key presses at any one time, although they might also see one of the
Ctrl, Alt, Shift and the Windows command key in addition to the four ordinary
keys.
Better USB keyboards can be labelled at
6KRO, meaning they can poll six ordinary keys and they also can see four
special ‘modifier’ keys in addition. These are better, but they’ll never be as
good as an interrupt driven PS/2 keyboard that demonstrates proper N-Key
Rollover, which USB can’t achieve currently.
Ghosts In The Machine
Some keyboards are sold as anti-ghost, so
what’s that all about? There’s a situation that can happen when two keys are
pressed at exactly the same time, where the system generates a third key you
never pushed: the ghost key. This is rare, but it can happen.
The
Topre switch. This radical switch design is a logical development of existing
switch designs to provide a better, cleaner action. However, the keyboards that
use it aren’t cheap
To stop this odd occurrence some keyboard
makers have instigated a form of software blocking that eliminates the extra
key press, but the downside of this is that it ignores that third press if it
really happens too, which is yet another problem.
This a limitation of the wiring matrix that
reads the keys and, as such, is difficult to combat entirely. The most common
place you’ll encounter ghosting or blocking is in gaming, rather than editing
text. As such, most of the keyboards with anti-ghosting tech are those designed
for this purpose. What they usually do is treat the WASD area of the keyboard
as special, so all simultaneous keys in this area are read, but it doesn’t mean
that the keyboard can handle any input combination without error.
The problem is more of an issue on USB
keyboards, because of the limitations on the number of keys that can be
simultaneously sensed, but even PS/2 ones aren’t entirely immune because of the
matrix on which the keys are electrically connected.
The Bounce
As a key is depressed, it eventually
triggers the switch underneath, and from the perspective of the computer the
contacts bounce to register multiple key presses. This is true irrespective of
what mechanism it is, and it’s something the system must cope with or typing would
be something of a nightmare. The way that this is handled is that once a key
press is recognised from a single key, then for a period of time further input
from that source is ignored until the key is considered ‘reset’. This is called
the ‘debounce’ and the better the keyboard the shorter this time is. A good
mechanical mechanism like one based on the Cherry MX switch has a debounce of
5ms, where a cheap keyboard might be a lot longer. The faster you’d like to
type, the shorter a debounce period you’ll need and want.
Filco
Majestouch
Mechanical keyboards always have shorter
bounces than those with rubber domes or other flattened designs, and it’s one
of the reasons that they’re better. However (and this is the catch), the
springs that create short bounce can also make these key actions noisy.
Time To Switch
When you start looking for keyboards you’ll
hopefully be told about exactly what switch the product you’re looking for
uses. The snag with this information is that most people don’t know a Cherry MX
Black from a Black Alps, unless they’re a hopeless geek like me. To help better
understand some of the nuances of key switch technology, I’ve created a chart
of some of the most common varieties (see bottom of page).
What’s important to know about these mechanisms
in respect to use is that switches like the Cherry MX Black are considered good
for gaming, because they’re not tactile and the tactile ones are generally
better for typing. Personally, I’d avoid the Alps design because it has a hard
ending to the press with no pre-activation, which can hurt you after extended
use. I’ve not tested them, but I’ve heard excellent things about Topre
switches, which depending on the specific keyboard can have a range of
activation forces, and they’re also very quiet (not being clicky).
There are others, but these are the ones
that are usually quoted, and it’s worth understanding what the difference is
between, say, a Cherry MX Blue and a Red. Understanding the switches can avoid
you ordering a keyboard that’s entirely unsuitable for how you intend to use
it.
