deskthority

I was looking at some stuff to see whether some smaller layouts could take advantage of certain keys being smaller than they are now... and saw that the Alps switches are designed to handle 18 mm pitch, as well as the 19.05 mm pitch that's standard. Alps even sold keycaps designed for that pitch.

What are people's thoughts on going to narrower pitch to reduce keyboard size?

I'll note that I'm actually at my fastest on a slightly reduced pitch keyboard, and one of my favorite laptop keyboards was 18.5 mm pitch. (My fastest boards are my Tactile Pro 4, my Model F 122, and my Acer Aspire One at 17 mm pitch. I suspect that if there were good switches under it, I'd do much better.)

Edit: So, here, have some comparisons.



Top is full layout, middle is tenkeyless, bottom is 60%.

Blue is the "standard" full pitch layout - for full layout, that's 23 x 7 U, for tenkeyless, 18.5 x 7 U, and for 60%, 15 x 5 U.

Yellow is a mildly condensed layout - full layout is 22.75 x 6.5 U (although in reality, most keyboards would go to 23 x 6.5), tenkeyless is 18.25 x 6.5 U (again, 18.5 x 6.5 U would be more likely), and 60% is 14.75 x 5 U.

Green is an extremely condensed 60% layout, at 14.5 x 5 U. This causes problems for ISO layouts.

Purple is the standard layout, but at 18 mm pitch.

Orange is the mildly condensed layout, but at 18 mm pitch.

Teal is the extremely condensed 60% layout, but at 18 mm pitch.

I have no long term experience with reduced pitch keyboards but I've noticed that some keys are easier to reach on smaller, otherwise inferior laptop keyboards.

BTW, the microTRON has a reduced key pitch.
17 mm
http://www.personal-media.co.jp/utronkb/spec.html

17 mm pitch is a bit insane IMO for a full travel (and that one is, at 4 mm travel) keyboard, although actuating near the top (Topre, Alps) helps with narrow pitch.

Typically, laptops 13" or larger usually have full 19.05 mm pitch keyboards, but some keys (top row, arrow keys) are often reduced pitch (sometimes greatly reduced).

Keycap shape also becomes more critical at reduced pitch, as it becomes harder to distinguish the keys. My Aspire One actually did a decent job of this despite the overall mediocre quality of the keyboard. However, some tapering is still possible - the Alps drawing is confusing, because I think it's showing two different keycaps under the same part number for 18 mm pitch unless I'm misunderstanding things - one at 16.05 mm per side, with a flat 12.02 mm per side top, and one at 17.3 mm per side, with a cylindrical 13 mm top. the Alps keycaps are two-piece, even, at 17.3 mm per side, 13 mm cylindrical top. If Alps likes to allow .7 mm, though, the underlying piece is 16.05 mm per side, allowing 16.75 mm pitch on Alps switches.

When we say pitch, we mean the distance between keys rather than just the size of the caps?
I'm reckoning A in this diagram. Which should be the unit size vertically, too, for full height rows.

Nope, neither A nor B.

This is pitch - it's center to center:
And, yes, on a normal keyboard, vertical and horizontal pitch are both 19.05 mm.

Now I'm wondering if sphericals would allow a 18 x 17 keyboard to be practical... (I do think a spherical profile would help even more on a reduced pitch keyboard.)

Here's something interesting, looks like a proposal for a study of 19 x 19, 18 x 19, 17 x 19, 16 x 19, and 17 x 17 pitches, and it references a Japanese study of 19.05, 16.7, 16.0, 15.6, and 15 mm pitches: http://oerc-org.siteburnerpro.com/docum ... 202010.pdf

The difference between 19 and 19.05 is very slight indeed. My custom board (like all of Matt3o's students) is 19 mm pitch. I can't tell the difference with standard sized caps.

Using Apple's laptop keyboards for a decade (including what passes for their default desktop keyboard now, too) I can vouch for the predictably crazy-making effects of mixing different pitches in the same layout. Their function/media row is notoriously touch typing unfriendly:

19.05mm is 0.75"
19mm would be .74803149606299212598"

And as I'm researching the standards... ANSI/HFES 100 now has a wiki page.

It actually requires 19 ± 1 mm pitch (with a 12 mm wide strike surface being recommended), so 18 mm would be OK, but I think ISO 9241-4 actually calls for 19.05.

Now to actually find a copy of ISO 9241-4 that isn't behind a paywall... I could've sworn I had a copy of the 1998 version (which isn't current, there's a 2008 version with a 2012 addendum) somewhere... (Or, rather, ISO 9241-4 has been split into 9241-400 and 9241-410.)

Simple facts about everyday objects require paywalls, clearly!

7bit wrote:19.05mm is 0.75"
19mm would be .74803149606299212598"

I think you mean 380/381 three quarters of an inch. (They're all about the fractions back there, you know.)

Apple chiclet keyboards have normal pitch on the horizontal, but lower pitch on the vertical.
I find that I type surprisingly well on such a chiclet keyboard even thought I can't feel the edges of the keys properly ... but I think that that is because I have already developed the muscle memory so that I know where the keys are.
On a chiclet keyboard with narrower pitch, such as on my Samsung netbook's keyboard, I do more errors.

bhtooefr wrote:Nope, neither A nor B.

This is pitch - it's center to center:

Centre to centre is the same as A.

Ah, yes, left edge to left edge would be the same. Never mind.

In my defense, I posted that before 10:00 on a Sunday.

In any case... got a copy of EN ISO 9241-4:1998 out of Scribd. Here's my copy: http://bhtooefr.org/files/EN_ISO_9241-4-1998.pdf

Uploaded some useless datasheet that I had lying around to get the free download. Reading over it now. It's not the current 2008 or the amended 2012 standard, but those have nasty watermarking on the PDFs and fun things like that.

ISO says 19 ± 1 mm, too, for what it's worth, with 12 to 15 mm wide and 110 mm^2 minimum area strike surface. All of that is shall. (It does say that outside of alphanumeric and numeric zones, pitches outside of 19 ± 1 mm are OK (but should be at least 15 mm) and may not be less than 64 mm^2 strike area.)

There's a study out of a Berkeley ergonomics lab that suggests that anything 17mm or bigger doesn't increase typing pain or typo rate for users with large hands and also improves things for users with smaller hands.

http://hfs.sagepub.com/content/early/20 ... 0812465005

Ah, so they carried out their proposal.

http://hfs.sagepub.com/content/55/3/557 is the latest version it seems.

I think that's a sign that 18 x 18 mm is gonna be fine. (I personally prefer something bigger than 17, and 18 maintains ISO and ANSI compliance.) The main problem would be keycaps, as that'll all be custom molds.

Here's a paper Fujitsu did in 1998, when they introduced a variation on scissor stabilization ("gear link"), and used it as an opportunity to play with smaller pitches (although, again, on Japanese test subjects): http://www.fujitsu.com/downloads/MAG/vo ... aper14.pdf