XO-1.5 keyboard

[John Watlington]

Hmm.   I need to communicate more.
There have been a number of changes in the XO-1 keyboard
since production started.

First, the flex circuit layout was changed to fix a problem with
the CTRL/ALT keys (the spacing bump for those keys was inexplicably
slightly below the minimum reliably reproduceable size of the printing
process).

And we started getting reports of keyboard tearing from users.
There is a tradeoff between pressure required to generate a keypress
and the thickness of the silicon rubber membrane used.   In the laptop
design process, minimize the required pressure (and increasing
the typeability of the keyboard) won out over the much less measurable
keyboard lifetime metric.

We changed the tool spacing by 0.15mm, which increased the reliability
without affecting the ease of typing too much.  This was made as a runin
change in production, in fall 2008.   Unfortunately, the reports from  
Uruguay
indicate that this was not enough to prevent keyboard tearing.

We have just cut a new set of tools for the membrane keyboard, which  
increase
the thickness of the vertical portions of the membrane and greatly  
reduce tearing.
They are currently being tested by Uruguay.   We will transition all  
laptops to this
keyboard once approved.

Finally, we are starting to look at making an XO version using a non- 
membrane
keyboard.  While not as water/dust resistant, it might be more  
suitable for
older children.

Cheers,
wad

On Mar 5, 2010, at 5:51 PM, Paul Fox wrote:

> john wrote:
>>> :-)  you're right -- it _is_ awesome.  wad seems to have mastered
>>> the art of getting the laptop to really go together right after
>>> the conversion.
>>
>> One of the things I asked wad to improve when he was looking for
>> things to fix for the XO-1.5 was the incredible flakey keyboard.
>> Everyone knows when I type an email message on an XO, because it's
>> always so full of typos that it's just not worth going back to fix
>> them all.  One of my XOs has a CTRL key that would press itself at
>> random intervals, which was really fun under Sugar.  One would think
>> that a keyboard designer would make very sure that the shift-keys  
>> were
>> more reliable than the letter keys (since they get pressed a lot more
>> often), but in the XO-1 it was the opposite.  I eventually tried to
>> batter my way through the alleged OLPC parts-and-repair process (and
>> failed); but somebody nice took pity on me and mailed me a spare
>> keyboard.
>
> heh -- i think that was me.  i think you have the keyboard that i
> no longer needed after installing my USB version.  :-)   fwiw, i'm
> under the impression that getting replacement parts isn't very
> difficult these days.
>
>>
>> Wad said improving the keyboard wasn't on the main program for 1.5  
>> but
>> he'd see what he could do.  Did anything happen?
>
> i recall that the keyboard density may have changed part way through
> XO-1 production (near the time that the new touchpad was introduced?),
> but i don't know that anything specific changed for 1.5.
>
> paul
>
>>
>> 	John
>>
>
> =---------------------
>  paul fox, pgf at laptop.org
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