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geekhack Community => Keyboards => Topic started by: Shyfe on Sat, 24 August 2013, 23:29:12

Title: "Simultaneous" keypress issue on KBT Oni
Post by: Shyfe on Sat, 24 August 2013, 23:29:12

I recently bought a pretty high quality keyboard, the KBT Oni Tenkeyless with Cherry MX Brown. Almost everything is great. However, I type at 160-190 WPM so when I press many keys consecutively, the keyboard may interpret them as if I am pressing them at the same exact time. It seems that some keyboards are capable of detecting the actual order in which I pressed them while others will always type the letters in a set order. Basically, if I were to press the keys "qwe" on my laptop at the same time repeatedly, I'd get all sorts of different key sequences like "qew", " weq", etc. However, on the KBT Oni, I will repeatedly get "qew", "qew", "qew". I thought this keyboard would be great for fast typists due to NKRO, but this issue is making me have even more inaccuracies. Does anyone know if there is a fix for this or if there are any keyboards where this is not an issue?

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: chill1217 on Sat, 24 August 2013, 23:41:36

holy crap you type fast.  do you use any special system?

on my realforce 87u 55g i am getting different key sequences for "qwe"

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: tp4tissue on Sat, 24 August 2013, 23:45:11

Seems like the problem is in your technique. OR your timing is off because the travel distance has changed dramatically between the laptop and cherry mx

(http://www.cute-factor.com/images/smilies/onion/07baa27a.gif)

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: FoxWolf1 on Sat, 24 August 2013, 23:51:05

I think I've heard of other keyboards having this problem. Weren't there reports of this with certain models of Das Keyboard? Can't say I recall any particular solution.

It is not something that will happen with all keyboards, though.

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: Soarer on Sun, 25 August 2013, 08:03:16

Yeah, IIRC, it was the first DAS that had transposition errors. People thought it was because of a low scanning rate, but when measured it wasn't particularly low. My theory is that it had a poor debounce algorithm - batch debounce can group keys up, and usually they're then output in scancode or HID code order (for PS/2 or 6KRO), or the order they appear in the report (for USB NKRO).

Pressing keys simultaneously doesn't really give any useful info for debugging the issue, since that's (hopefully) not how you type! A slightly better test is to bring a straight edge down on a few keys at an angle, so you'd expect them to come out in a certain order.

I don't know much about the KBT Oni though, so can't really say what might be causing the transpositions. The NKRO over USB isn't really needed for typing (an NKRO matrix using 6KRO USB should be sufficient), but on the other hand shouldn't be causing this problem.

Technically, the features needed for fast typing are a high scanning rate and a decent debounce. Preferably individual debounce for each key, although batch debounce might be sufficient with a fast scan rate (say, 1000Hz) and tight timing (say, 5ms). Trouble is, manufacturers are not particularly open or clear about these specifications. So, currently, I think the only way to be absolutely sure of what you're getting is to go with a custom controller, for example one of bpiphany's or a Teensy with hasu's code (or my code when I release the controller version generally).

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: dante on Sun, 25 August 2013, 08:23:23

Some Filco Zero's also had this issue - though those aren't going to be exactly easy to run into.

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: Shyfe on Sun, 25 August 2013, 20:05:04

Quote from: tp4tissue on Sat, 24 August 2013, 23:45:11

Seems like the problem is in your technique. OR your timing is off because the travel distance has changed dramatically between the laptop and cherry mx

Show Image

(http://www.cute-factor.com/images/smilies/onion/07baa27a.gif)

I'm absolutely certain that I'm pressing a certain key before the other, but it is appearing the other way. I really believe it is because I am pressing them so quickly in succession that it seems like I am pressing them at the same time, but I am absolutely certain of the order I am pressing it in.

Quote from: chill1217 on Sat, 24 August 2013, 23:41:36

holy crap you type fast.  do you use any special system?

on my realforce 87u 55g i am getting different key sequences for "qwe"

It's not really a set system. It's basically not following any standard sort of typing system but adapting your hand placement depending on what word you're typing so that you can use a different finger for each consecutive letter. The idea is to not have the same finger type any two consecutive letters so that you will be able to type a word very rapidly. Note, this is just something I do naturally and didn't try to learn. I'm just trying my best to analyze what I do and explain it.

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: Shyfe on Fri, 02 May 2014, 21:26:45

Sorry to bring this topic back up, but does anyone know if there's any way to replace the firmware or controller for this?

Title: Re: "Simultaneous" keypress issue on KBT Oni
Post by: hasu on Sun, 04 May 2014, 05:05:29

Try posting photos of PCB and MCU. Maybe someone can identify.