[Arm-netbook] Keyboard

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sat Aug 27 17:12:08 BST 2016

crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

On Sat, Aug 27, 2016 at 9:03 AM, Vincent Legoll
<vincent.legoll at gmail.com> wrote:
> Hello,
> First, congrats on the campaign success !


> I tried searching the ML archives & rhombus site, but couldn't find it.
> Is the laptop's keyboard only option the
> Keyboard: Chicony P/N MP-03756GB-5287.

 and associated variants, yes.  see

> Or can a backlit one be substitued easily? I.e. No other HW redesign...

 substituted yes... easily... well... a replacement keyboard has
(physically touches) the following surrounding parts:

 * back runner (left and right)
 * left edge, right edge
 * middle strut (underneath)
 * touchpanel tray
 * PCB1 support (left side)
 * Battery support (right side)
 * left front kbd support (for compartment)
 * right front kbd support

 now, given that work on each of these, to fit a new keyboard, would
take about 2-3  days of CAD work, 3-4 days of re-printing followed by
iterative redesign *EACH PART*, a simple-sounding "can we replace the
keyboard with something different" stacks up to a staggering 7-9 weeks
just on 3D CAD work.

 then PCB2 also needs to be redone, not just in terms of connector
sourcing but also component placement and connector placement.  after
doing a feasibility study of approximately 2 weeks and sourcing the
parts (another 2-3 weeks) this takes an estimated 1 week for the
design plus another 4-6 weeks for the PCB to be manufactured and
components source, purchased and assembled.

 however before you get to that, you have to bear in mind that the
connector placement may have a cascade knock-on effect on the PCB
shape as well as the CAD design to *fit* the new PCB shape, now you're
looking at an extra 2-4 weeks of iterative 3D work.

 then also the keyboard's matrix has to be reverse-engineered because
it's extremely unlikely that the manufacturers will tell you how it
works.  that requires disassembly of they keyboard, tracing its tracks
and documenting them: this takes another 2-3 days.

 then you need to reprogram the firmware.  with the current firmware
already in place that would take maybe a couple of days.


 simple-sounding question "can a new keyboard be fitted"... answer is:
it's about 4 months of full-time work.

> Or maybe the laptop case can be modified to allow placement of a few
> leds around the screen that would get light on the keyboard. I had
> this on an old T42p and it was better than nothing.

 that would be much simpler - it's still abouuut... 2-3 weeks of work,
redesigning casework, that's assuming no LED circuits are needed and
there's a convenient place to draw power off of.  if it was under PWM
control of something (to change brightness) that's.. 3-5 weeks of PCB
design work and PCB assembly, 1-2 weeks of component sourcing and

> That would make the laptop better suited  to night use.
> Wdyt?

 *deep breath*.... get a small $2 torch from walmart :)


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