06 October 2008

Building your own custom Pico ITX system

Alternate title:  the parts you will have problems finding.  A follow-up, of sorts, to this post about how I can find the strangest ways to kill time.

Yes I did, indeed,  decide to do something nuts: custom build a Pico ITX system using the Via EPIA PX10000G.  This is not the Artigo kit they sell, which is 'custom' in that you have to put the tiny, deck of cards size motherboard into a case and screw some screws in... no this is the 'hey wouldn't it be neat to put a computer in this?' idiocy of having a cute aluminum frame to put something into which sounds incredibly simple, but is extremely difficult.

This is not a 'case mod' custom job: the case is a piece of cast aluminum that used to house a Netgear SC-101 'network appliance' duly dubbed by many 'the toaster from hell'.

This means that I will need to do a bit of DIY custom fabrication of things like a motherboard tray, and finding ways to mount switches and such.  So the effort to find all the piddling pieces I need to actually do all this starts with the fabrication materials, switches and such.  Most of them I got from Performance-PCs, and much thanks to them for sheets of nice looking aluminum, nibblers, vandal resistant switches, assorted wiring, cabling and so on.  Really the Lian-Li case modification stuff is really quite nice with an aluminum case and should serve quite well once I get things rolling.  Also to be mentioned is Xoxide and their somewhat smaller array of materials which has some things that Performance-PCs doesn't have.

Going through my list of 'things a small system must have' includes such things as audio jacks, and you can get a nice board for the Pico ITX at Logic Supply, along with many other EPIA pieces and parts.  Also have to mention them for EPIA power supplies, and they are competitive in that pricing, too.  I bought the main board, itself, from Ewiz/NewBiiz/SuperBiiz and probably a few other names to boot.  They had a good price via Pricewatch.com on my sidebar, and it was worth saving the money as it balanced out shipping costs.  Speaking of which, my old standbys of Newegg and Mwave also get nods for some things like notebook hard drives and a nice dual notebook drive to 3.5" case bay adapter from CRU-dataport.  If you are cramming a lot into a small space you need notebook drives, and if you are going to sacrifice one out of three bays of the SC-101, you might as well get two drives in it.

But getting the major components - motherboard, memory, drives, bay adapters, switches and faceplates - that is only the *beginning*.  Yes you have all the parts and then find out that Via has decided to pull a swift one on you.

Not only do they use non-standard pin-outs for things like where you plug in the momentary switch on the motherboard, but they use smaller than standard screws for their motherboard.  And these two items begin the tale of woe...


The Quest for 2.0mm pitch wire to board leads

This is normally a *snap* as there are tons of places you can go to get lead wire that is pre-socketed so all you have to do is push the leads into the motherboard and then just do a bit of finagling with the tinned leads to get a solid connection to whatever it is you are hooking up to the motherboard.  Those usually use 2.54mm pitch connectors.  Via uses 2.0mm pitch connectors.

Everyone on the planet uses 2.54mm pitch connectors for standard motherboards.  I can find oodles of suppliers for lead wire that is already put into connectors and has tinned leads.  But 2.0mm pitch that isn't biased?  Bwahahahahahaha!!

I've tried all the major supply houses and can get the individual components, but a minor bit of cable assembly for 'one-off' pieces?  And, yes, you name it and I've checked it both in the US, UK, Germany, and Thailand.  Trying to figure out what I can get from China is a bit much, considering how their front organizations operate, and I've had it with enigmatic descriptions of what companies may or may not offer from China via these centralized sites.

After weeks and weeks and weeks of searching there are a few places where you might get the stuff, but so far I've found its no dice due to the wire sizing and board connecter size.  The prime one of which is SparkFun for all your electronic weirdnesses and parts you can't seem to find anywhere else.  A great place for robotics projects and such and you can find 2.0mm pitch lead wires there... just not the right connector size for the 2.0mm pitch.  If you want to really part it out and DIY and make your own lead wires, then Action Electronics is a good place to go.

Go ahead, go to GlobalSpec, Octopart, Mouser, or any of their equivalents for this stuff!  Knock yourself out!  I don't care to recount the DAYS I have spent going through them... verging on weeks at this point.  I really do not want to get into the 'strip the wire and crimp the sockets and tin my own leads' stage of things.  And I am still trying SparkFun and a few other places to see if the robotics community has this problem tackled.


You want *what* size screws?

Ah, if you don't know about screw sizes and never intend to build a custom rig and do it DIY, then you will never need to know this.  And if you are only used to working with full size PCs and never intend to do otherwise, this is also terrain you won't cover until one of the EPIA systems gets wildly popular, everyone wants one and no one will have the screws for them.  Fun was not had.

First the screws in the SC-101 were Torx screws.  They were *not* M4 screws.  Nor are they exactly M2 screws.  Nor M3 screws. Nor M2.5 screws.  They are just between M2 and M2.5 screws which yields no real easy English measurement, which falls on both sides of the M2 and M2.5 sizing.  My guess is that they are either fine thread M2.5 or coarse thread M2 screws.  My solution will be to use M2 screws with Blue Loctite (242).  My thanks to Henkel's Loctite folks for making a good solution for this sort of thing.  I had to find some Red Loctite for my Ruger and mounting the Weaver Scope Mount on it, and I finally chose the lowest end of Red Loctite (262) which doesn't need a heat application to get it off.  Yes!  I am going to cheat!  It is either that or drill and tap my own screw holes and hope I don't ruin the existing ones in doing so.

So where do you head for screws and associated materials?  Well there are two choices out zillions... if you want cheap and easy it is the Tools, Auto & Industrial part of Amazon.  Really!  You wouldn't believe the good stuff they have there, including super thin shim stock for doing case finishing.  What a selection of stuff... really, recommended.

The other place is McMaster-Carr, which has a great selection of everything from small parts to everything you need to outfit your home.  It is a bit more expensive, but if you decide on 'one-stop shopping' then it is worth checking out since it scales from the small to the large, equipment-wise.  Couldn't find 2.0mm pitch lead wire there...


Where is the project build?

I have all the major parts!

The wire to connect it all up and the screws to tighten stuff into where it is going to have to stay put?

Researching the Red Mafia or the connections of Monzer al-Kassar is a *snap* compared to this... on the plus side I did get to replace my electric drill that went missing with a nice rechargeable from Milwaukee.  It is their sub-compact driver and works perfectly.  Bought used from the factory with full warranty.  And I did buy the necessary taps for doing my own threaded screw holes from Amazon...

2.0mm pitch lead wire?

The Quest, unfortunately, is The Quest.

And that is what is killing my spare time.

That and blowing off steam writing a Star Trek story...


Beto_Ochoa said...

Maybe the screws are 2-56 UNC?
Only .006 larger diameter and near identical thread pitch

A Jacksonian said...

Hmmmm.... possible!

I've been through just about everything in my 'misc. screws', but its worth a try. If not, that is why we have Loctite.