[Arm-netbook] My little idea...

Wed Oct 16 04:17:47 BST 2013

Here's the image --> http://i.imgur.com/EeIByb5.jpg

That's a scan of Ye Olde-Fashioned Hand Drawn Electronic Schematics. 
It's a pretty minimal setup, TBH, one USB port for a powered (or not) 
hub, a simple (if a little clumsy) Mims-inspired momentary-switch power 
on-off setup, and R-2R ladder DACs (and some transistor based 
level-shifter buffers) to a VGA port. Ethernet port is a bit weird -- 
it's really a Gigabit+POE connector where I've tied the POE bits to 
ground and used only half the transformer. (The GPIO ports to Ethernet 
LEDs are strictly optional...) I'd LOVE the part numbers for your 
cheaper parts -- the PCMCIA card slot I found was over $6 and the 
Ethernet jack was IIRC like $14.50 (geez louise!!).

You could actually build this on perfboard (like the crap at Radio 
Shack). You'd need to have custom dongles for the card slot and SATA 
port, and the USB port would be on a header -- but that's not hard. Use 
a pair 80wire IDE cables from a (slightly) older computer, cut them up 
to make a pair of 68wire cables, tie every other wire to ground on both 
sides... use the leftovers for the SATA connector in the same way. It 
would probably work OK-ish as long as the video resolution didn't go too 
high...

On 10/15/2013 10:58 PM, Christopher Thomas wrote:
>
>
>
> On Tue, Oct 15, 2013 at 8:38 PM, Christopher Havel 
> <laserhawk64 at gmail.com <mailto:laserhawk64 at gmail.com>> wrote:
>
>     Just a little something I cooked up ;) no pictures yet, but here's
>     a wall of text about it...
>
>     I've got hand drawn schematics made up for an EOMA-68... er... I'm
>     calling it a Carrier Board for now (the PCB that the CPU card goes
>     into). This one uses only through-hole components, and all but two
>     (the PCMCIA slot and, oddly enough, the Ethernet jack) are very
>     cheap. The idea is that someone like me who is rather a bit of a
>     dunce with the soldering iron can still put it together in a
>     dedicated weekend, if so inclined. *That is, a person with fairly
>     beginner-level hobby skills can buy a fistful of parts and a CPU
>     Card, etch a PCB (or get one from somewhere) and after a few hours
>     of lead fume inhalation, has a complete computer in their hands.*
>     That's a huge gift, I think, to the  Maker community, not to
>     mention the technically-inclined poor folk out there (I *know* I'm
>     not the only one!)... seriously, it sounds like good stuff to me.
>
>
> With the exception of the Through Hole components, we're right there 
> with you... here was my idea I am currently in the process of building 
> right now.
>
> http://rhombus-tech.net/community_ideas/carrier_board/
>
> Regarding the Ethernet component, I have a Gigabit Ethernet jack that 
> has magnetics and is through hole that is only $3. Also, I have a 
> Hirose PCMCIA connector that is ALSO very cheap ($3.69), and is 
> through hole as well. ALSO, it can be had for free from 
> "NeedASample.com". The board I mentioned above will be listed as 
> opensource and free to download and modify.
>
>     My two rules for designing were (1) no surface mount anything at
>     all period end-of-story, and (2) use as many very standard parts
>     as possible. Every component can be had at Mouser Electronics in
>     single unit quantities.
>
>
> My consideration to this would be, while Through Hole is definitely 
> easy, SMD is ALSO easy (within reason), it is only perceived as 
> complicated due to the size differences. SMD components aren't 
> necessarily more fragile, and they are certainly manageable for the 
> common person. I have taught several high school classes and freshman 
> college courses on SMD soldering by hand with commonly available 
> tools. My most common recommendations, 1) Clean TIP, 2) Flux, 3) 
> Steady but abundant heat availability. Also, if soldering SMD, for 
> passive components, it's easier to stay within the 0805-1206 range, 
> and TQFP/SOICS, QFN and BGA ARE doable by moderate-average skilled 
> people, but just require more patience.
>
>     The Ethernet jack has the magnetics built in, so it's
>     (unfortunately) the most expensive part on the board -- but I
>     couldn't find a through-hole Ethernet transformer... I've probably
>     also omitted some necessary things out of simple ignorance (I have
>     a hunch that there's more to the USB connection than four wires, a
>     power supply and data feed, and the connector itself, for
>     instance). I'm more budding hobbyist with this stuff than anything
>     else -- but hey, you gotta start somewhere, right? ;)
>
>     The only thing I don't like is that it still requires a custom PCB
>     unless one wants to do some very creative dongle-making...
>     probably doable but it'll be very ugly in a number of ways. That
>     said, I'll be quite surprised if this design cannot get away with
>     using a single-sided PCB -- meaning any shmuck who can get to eBay
>     can order the supplies to make the board at home if they want to.
>     (Sounds a little like me!)
>
> Most boards that require high current, or impedance matching will need 
> to be 2 layer at a minimum, and 4 layer is recommended for the larger 
> component counts. A simple carrier board like you are describing has 
> already been made
>
> http://rhombus-tech.net/community_ideas/micro_engineering_board/
> , and it consist entirely of through hole components.
>
> The Second Revision to this board will be going out for prototyping 
> this week. Pictures and Details to follow this weekend.
>
>     If anyone wants to try reading my horrible chicken scratch I'll
>     send out a link to a scanned copy, otherwise I'll try and work up
>     the motivation to move it into my graphics software (CorelDRAW
>     X3), since, although I have a copy of Kicad, I never really
>     bothered to learn how to use it properly...
>
>     Any interest at all?
>
>
> There is TONS of interest, and the market is there. My company, and 
> others, will be releasing several iterations very soon, all open 
> source, and easy to purchase, build, or assemble. They will be easy to 
> send to places like BatchPCB, SeeedStudio, or even your local 
> hackerspace (for those that can do 2 layer etching).
>
> I have given 3 Presentations in the last 2 weeks, they have all been 
> received with very warm and interested queries, with things like "Do 
> you know what I could use this for?! When can I buy it? Can I have 
> this sample?! How many can you sell me?"
>
> Your ideas are very much welcomed, and if you like, I, or any number 
> of people on here, would be more than happy to look at what you've 
> got. Or you can post images to imgur and include the links via a new 
> topic thread to let everyone see.
>
> And if you have any questions, please feel free to call or email me 
> any time, or post a question to the list, and someone should get back 
> to you shortly.
>
> And welcome to the list/world of EOMA and embedded ARM.
>
> Christopher Thomas
> Firemoth Industries, LLC - Owner
> christopher at firemothindustries.com 
> <mailto:christopher at firemothindustries.com>
> cell: 214-458-5990
>
>
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