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Low-cost embedded mobo

The bottom line is: You've told us you have problem X, and you're getting suggestions based around that. If you really mean "Someday I will have problem Y and I want to be able to solve that problem without ever having to change the hardware" then the suggestions might be different.

What you have to ask yourself is:

  1. Will customers with old units already fielded be interested in whatever new bells and whistles you can come up with in software upgrades, or are they just paying for hardware they'll never use?

  1. Are you sure that you're *ever* going to need any functionality of Linux, or the mini-ITX solution? Is it likely that upgrades to use such functionality will correspond to major product line remakes anyway?

If your customers are willing to pay $400 for a unit that does X,Y,Z functions (ONLY), then what sounds more sensible: spend $50 build cost per unit on an optimized solution and make $350 profit, or spend $150 per unit build cost, make $250 profit, and hope that future software upgrades will earn you >>$100 net?

$60 - motherboard $15 - PSU $20 - RAM $20 - bootable media

$115 + housing.

Your route also has complications with EMI (it's a big, fast circuit), and appallingly high power consumption for the described application.

Remember that mini-ITX hardware follows *PC* life cycles. In 6-9 months you will not be able to buy absolutely identical hardware. In

12-15 months you will probably need minor mechanical rework to fit whatever is on the market. In 24 months you most likely will not be able to buy one single part that is in today's design.

I'm not saying Tern's products - or indeed ANYONE's products - are the answer - I think a cheap all-in-one microcontroller would be way more than you need, and it would have a total BOM of $40 or so including housing - but I hate seeing a really suboptimal solution being used when there is really no justification beyond a vague assertion that "it might be useful someday".

Reply to
Lewin A.R.W. Edwards
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You make a lot of good points. Long term stability of design can be very important. Good luck finding a PC motherboard identical to the one you bought 5 years ago, unless you're searching on eBay or surplus vendors.

The ultimate answer is (of course) application specific so only Andrew knows for sure what will work for his design. As much as I'd like to believe our product is always the right choice, sadly, I have to admit sometimes that isn't the case!

I hadn't seen the micro-ITX before, so it's an interesting read. Fundamentally, these are intended for very different applications (which is basically what you were saying in your post). Technology wise... totally different world. We have customers that primarily need parallel and analog I/O, drive small solenoids/relays, interface with small kpad/lcds, etc... and do it with minimum power at minimum size (2.1 x 2.35 inches and 130 mA @ 5V, compared to the micro-ITX board at 6.8 x 6.8 inches and.. probably many times the power).

For most of our customers, the mini-itx would not be a viable alternative.

Even from a price perspective, I don't think this will compete in the same market. Clearly VIA is already producing these in volume (and pricing it that way for retail customers), and I doubt they have much margin left for significant OEM discounts. Andrew, I even question the GBP40 pricing you guess for 100 units. The FB is a firm $79 @100 units (and $34 @1000 if you get ambitious), and there are many other similar products in the same price range.

But I really don't know how PC (or these sub-PC) manufacturers price their products these days, so maybe you're closer than I am... I'd be interested in hearing the number when you get a firm quote from them!

But back to the practical matter at hand... I did notice that these VIA mobos only support 1 serial port. You'll need to use USB/ethernet for your PC/modem connections if you go this route. I'm not sure, but I doubt the system is bootable off your USB storage. You'll probably need some kind of IDE boot device... although you can probably pick those up at relatively low cost as well. All in all, a fun hobbyist system.

You definitely have a lot of options, Andrew!

Reply to
Chon Tang

The lowest-end EPIA board, with a 400-someMHz Eden processor, requires about 3A on the 3.3V rail, 400mA on the 12V rail, and 1A on the 5V rail, IIRC. The multi-rail requirement is also very irritating.

In the USA, the lowest-end board (out of production, I believe - it's a special order now) was just under USD100 qty 1, and prices went down to $70-odd in 100s IF you could get set up with the distributors. Not possible to obtain it at retail in that price bracket.

The BIOS, like most modern implementations, supports booting from USB floppies, which includes USB "pen disks".

Reply to
Lewin A.R.W. Edwards

This thread is probably already dead... but just for later reference, I did check with the folks at mini-itx, and they quoted me £58.50 at qnty 100. That's less than a £5 saving from the qnty 1 pricing, and equivalent to about $97USD.

Reply to
Chon Tang

"Alcuin of York" schreef in bericht news: snipped-for-privacy@4ax.com...

Top-posters ought to be shot in the neck.

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Reply to
Frank Bemelman

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