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Why the Raspberry Pi Won't Ship In Kit Form
An anonymous reader writes "A post at the Raspberry Pi blog shows an image containing the device's SoC and memory chip to help explain why the tiny PC won't ship in kit form. Clearly, the chips are so small, and the solder blobs required so tiny, that most people would mess up doing it by hand. Add to that the fact one chip has to sit on top of the other, and if you're a millimeter out, your chips are fried."
The post also addresses the use of closed source libraries for graphics acceleration.
Don't forget the reflow oven, so not only do you need superhuman skills, but you need a specialized tool that effectively nobody has.
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I still want 10 of them...
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The only assumption I saw was that most folks would botch assembly due to the teeny smd tolerances. It seems pretty reasonable to me. I don't know a lot of people with reflow ovens or hands that steady. And at $25 & $35 for the assembled models, I don't know why people would really want to.
The stories about this board need to stop, at least until they ship the thing. "We bought the parts". "We soldered them on", etc. do not each need a separate story.
Of course you don't ship kits of SMD parts, especially ball-grid array parts. Such a soldering job is cheap in a production environment, and a huge pain even with the right equipment in a small shop. (It's done in production by printing a solder paste layer on the board with a mask, and the final alignment of the pads is done by surface tension in the molten solder. It's all about temperature control and solder paste depositing. Once the production line is tuned right, it works quite consistently.)
So, anyone who does it successfully would achieve a rare accomplishment, through hard work, diligence, and skill.
And for those ten to twenty people out there? The phrase I'm looking for is "not a significant market".
If you really want a kit you can buy an assembled board, de-solder all of the components, and *make* a kit.
The kind of person who can solder BGA are also usually the kind of people who can acquire parts and produce PCBs.
If you've got the tools to do it, just buy the pre-assembled system and remove the solder. (Heat-gun soldering stations usually come with a removal gun as well.)
Voila, you've got your kit.
Now put it back together. Now you've done not just one, but TWO difficult, unnecessary things.
I worked with one woman who was a brilliant solderer. Production put a part upside down and she was able to solder it on so it worked. (For firmware development, bought me two weeks of dev time.) It was a QF44 PIC, I was astonished when I saw it.
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So you're saying if you care about video quality you should spend more than $25?
No the assumption is that you don't have the capacity to solder a BGA at home. You don't do this with a soldering iron, you do it in an oven, and you have to place the part precisely enough that it can self orient. I have heard of hobbiests doing this chip-to-pcb with larger pitched BGAs, but not fine pitch, and not chip to chip. I just don't think this is a good use of time or money, considering you will probably break a few.
But if you really want to do it, the gerbers are out there. There are lots of cheap board fabs, use one of them, then just go acquire the parts from digikey.
I want one assembled AND TESTED.
I'll pay for that.
debugging a software bug (my own code, say) is hard enough without second guessing the hardware.
csb: a friend of mine is trying to convince me to use an arduino mega (high density smd-only chip) where I'm currently using the skinnydip28 version of the regular 328-style arduino (which is .1" thruhole and easy to deal with). at the very least, if I was moving to a mega (25xx class), I'd insist on it being on a carrier board AND that board being built to high spec and the cpu tested on the board before being delivered to me for assembly into a larger system. I refuse to have to worry about the cpu AND the rest of the system (being a small company). I cannot find good mega-class chips already on carriers (.1-friendly carriers) AND tested AND by a company I'd trust to actually care about quality. being able to buy it pre-tested is key, to me.
back to r-pi: I'd want this to be known and tested as a FRU of its own. the thing is small enough to be its own field-replaceable-unit in a larger embedded system; and if any part on it is bad, the whole thing gets replaced.
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I don't know why people would really want to.
You clearly aren't the target market for a kit form, then.
Seriously, though: the world is full of people who want to do difficult, unnecessary things. It is a human-being feature. All Raspberry Pi has to do is say "Kits are not covered by warranty, period."
In my class I probably was the best at designing PCBs and at soldering and I must disagree with you. Times have changed -and I'm also getting older- and I find it hard to sensibly compete -even as a hobbyist- with mechanical, industrial level soldering, which is what the Raspberry hopefully meets. Also, trying and failing is probably less of a nuisance than trying, nearly succeeding and winding up with weird situations because of soldering issues. Spoke as a tinkerer.
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Really? You don't think the bad publicity they might get if lots of people report "I bought a kit and it failed" is a sufficient reason for them to refuse?
Come on man, its a hobby. When a dude puts together a 1000 piece puzzle you don't pee all over it by claiming you can buy a poster of the same picture and thats a better choice because you don't have to put it together... That kind of misses the point.
You do have to admit that there would be a ton of people purchasing the kit for no other reason than to save $3, and then break it and attempt to return it for a refund or hound their support email.
Perhaps if it was legal to sell kits specifically with NO warentee at all and a no return policy, then it may work... But in many countries that isn't even an option.
To take your puzzle example, yes people who do puzzles as a hobby are fine, just as people who actually like to assemble circuits like this would be fine.
But the people trying to do nothing but save a buck are the exact type who would purchase a puzzle, put most of it together, then bitch that it doesn't at all look like the poster due to the wavy lines between the pieces, and return it demanding more than a full refund at the puzzle makers expense.
I would like to believe after the first few production runs of fully built units, that later on they would put some effort into selling the specialty parts (PCB, pre-flashed chips or roms, harder to source components like odd freq crystals, etc) and put up the parts for sale individually along with the BOM and schematics.
That's the only way around the warentee problem with kits, and the only way to make it too much trouble for the people trying to only save three fifty. For electronic hobbyists, working from a BOM and schematic is business as usual, and not really any extra work we weren't expecting anyway.
Then everyone is happy!
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