[Arm-netbook] micro desktop

[Christopher Havel]

On Thu, May 29, 2014 at 12:33 PM, Luke Kenneth Casson Leighton <
lkcl at lkcl.net> wrote:

> http://rhombus-tech.net/community_ideas/micro_desktop/news/
>
> as promised the micro desktop is being developed, news and features on the
> page.
>
> l.
>

What voltage is the power input? 5v DC I assume? Be aware that 5v power
supplies on eg eBay (when the customer wants to replace things later on)
can come with either 5.5*2.1mm or 5.5*2.5mm plugs. A 5.5*2.5mm plug in that
socket will physically fit, but it will heat up and burn out the jack --
and the less-than-ideal connection will inevitably screw things up in other
ways as well...

I can think of two ways to fix this. One is to make it a 5.5*2.5mm jack
(this is probably simplest, easiest, and best). The other is to label it
clearly on both PCB and outer enclosure. If the second idea (labeling) is
chosen, then it becomes (logically) necessary somehow to find some means of
convincing the consumer/customer never to put a 2.5mm ID plug in that jack,
which is a very difficult task. I've got decent eyes and *I* can't see the
difference, and a lot of people in the US (especially in the region where I
live) seem to be very good at ignoring warning labels and, consequentially,
doing very stupid things that break everything (whereupon they complain,
usually through the courts, that it wasn't labeled adequately).

There is an added bonus to making the jack 2.5mm ID -- most 12v power
supplies with barrel jacks are 2.1mm ID -- meaning that if a consumer is
totally clueless about voltages and how not to fry a computer by severely
overvolting it, they will be largely unsuccessful in replacing the 5v wart
with a 12v wart... it just won't fit.

You really do want to be thinking of the "Doug Hefernan" type here. (That
was the name of the character portrayed by Kevin James on a sitcom called
"The King of Queens". I can easily picture him saying "oh shut up all of
these adapters are the same" and plugging in the wrong one to the tune of a
dramatic shower of sparks... there are a LOT of people Stateside who are
like that, sadly.)
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