i've been using a das iii for several months, and since the beginning, accuracy has been a problem at higher speeds. for example, i found myself typing 'teh' instead of 'the' a lot more frequently on the das than on other keyboards. i've also noticed what could be best described as input lag when i get a nice typing rhythm going. not terribly huge, but just enough to be mildly annoying.
i always thought that it was me, but now i'm not so sure.
i stuck with the das because i like the feel and sound of blue cherries, the keyboard's decently made and looks kinda neat, adn (<--i'm using the das iii now and this is another typo pattern i make on a regular basis, and i'm going to leave this as is for reasons that will become apparent later) the 12-key rollover is a nice featuer (<--another one).
ironcially (<--another), it's the rollover behavior of the das that clued me in.
here's the das with the a, s, d, and f keys pressed at the same time. first with just one hand, then with the other, then with the index and middle fingers on each hand, and even with the index and middle fingers of my left hand hitting d and f, and the index and middle fingers hitting a and s:
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
asdf
here's an alps glidepoint (ps/2), chosen at random from my keyboard collection:
fdas
fdas
sfda
fdas
asfd
fdas
asfd
sfda
sfda
sfda
asfd
fdas
asfd
fdsa
fdas
asfd
asfd
sfda
fdas
asfd
sdaf
asfd
asfd
sfad
sfda
asfd
sdaf
asfd
asdf
asfd
asfd
sfda
asfd
asfd
asfd
asfd
sdaf
dasf
dasf
sfda
asfd
i did these 4 keys because the glidepoint works okay with them.
see a pattern here?
the das always gives the same rollover pattern, but i know for a fact that my fingers weren't hitting the asdf pattern exactly in that order each time, and my fingers certainly weren't actuating those 4 switches at EXACTLY the same instant, every single time (it would make sense for the keyboard to output a given pattern consistently if the keyswitches were actuated at precisely the same instant because typing is inherently character-by-character...the keyboard essentially has no choice but to give priority to one key over another if both are hit at exactly the same instant. either that, or block the keys completely.)
as i started seeing the pattern emerging on the das, i even intentionally 'biased' the keypresses ever so slightly to try to get a 'fdsa' pattern to show up, but it didn't, even when i KNEW that that pattern would show up on other keyboards with the keys pressed that same way (you get a feel for these things after typing on keyboards for years and years).
now, regarding the typos i pointed out at the beginning:
das keyboard, e and h keys:
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
he
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
eh
glidepoint:
eh
he
eh
eh
he
he
he
he
he
he
he
he
eh
eh
eh
he
he
he
eh
he
eh
eh
eh
he
he
he
he
eh
eh
he
das, d and n keys:
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
dn
glidepoint:
nd
nd
nd
nd
nd
nd
nd
dn
nd
nd
nd
nd
dn
nd
dn
nd
nd
nd
nd
nd
nd
nd
nd
dn
dn
dn
dn
dn
nd
nd
dn
nd
dn
nd
nd
dn
nd
das, e and r keys:
er
er
er
er
er
er
er
er
er
er
er
er
er
re
er
er
er
er
er
er
glidepoint:
re
re
er
re
er
re
re
re
re
re
re
er
re
re
re
re
re
re
re
er
er
das keyboard, i and c keys:
ci
ci
ci
ci
ci
ci
ci
ci
ci
ci
ci
ci
ic
ci
ic
ci
ci
ci
ci
ci
ci
ci
ci
ci
glidepoint:
ic
ic
ic
ic
ic
ic
ic
ic
ic
ci
ic
ic
c
ic
ic
ci
ic
i don't know why the das behaves this way, but perhaps it is related to the way it detects and handles simultaneous key presses, and might also have something to do with the input lag i sometimes perceive when typing very quickly on the das.
what i'm speculating is, and this is based solely on observation, perhaps there is a certain length of time during which if multiple keys are pressed sequentially, the keyboard detects them as being simultaneous presses. but because typing is done character-by-character, the keyboard needs to send the characters one at a time, but with multiple simultaneous keypresses, it has to send them in SOME kind of order, which it does consistently (thus the asdf, asdf, asdf).
so, for the sake of argument let's say that this length of time were 50ms. if i were to press the h key followed by the e key within that 50ms, the keyboard considers that simultaneous, and sends out the sequence as 'eh', because that's the way it was programmed. so i'm flying along and i've ended up with 'teh' instead of 'the'. the keyboard can't keep up with me. but if i slow down a bit and hit the e key, say, 60ms after the h key, the keyboard sees two separate keystrokes, and in the correct order.
when i do the rollover test, i bet i'm hitting the e and h keys within that 50ms. in reality, sometimes i'm hitting the e followed by the h, and other times the h followed by the e, and every once in a while hitting them at exactly the same instant. but it doesn't matter, because as long as both keys are hit within 50ms of each other, the keyboard sees the inputs as simultaneous, and outputs 'eh' each time.
now maybe the keyboards i've used previously had a shorter 'lag' (for lack of a better term) time than 50ms, and that's why i haven't had this problem with them.
but, thinking back to what dmw said in the 'what's this?' thread about how usb keyboards work, this problem may not actually be the keyboard's fault, perhaps it's due to the way usb keyboards are handled by the operating system (windows xp in my case) that is causing this behavior.
the das is the first usb keyboard i've used on a regular basis, all of my previous keyboards have been ps/2.
at work tomorrow i'll have access to other usb keyboards to test.
in the meantime, any thoughts?