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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.
How about we stop posting a Raspberry Pi story every goddamn blog post and save the talk for oh... I don't know... when the god damn thing actually ships?
I've been throwing my money at the screen for months and NOTHING'S HAPPENING!!!
Should read EVERYONE without the nimble fingers of a child, the steady hand of a special forces sniper, and the sharpest soldering iron this side of the sun.
For every benefit you receive a tax is levied. - Ralph Waldo Emerson
BGA packages are intimidating, even to a guy who's been hand soldering other SMD packages since around/before 1990 (that being me)
Plain SMD is easy to do by hand, even the 0402 stuff.
The thing with BGA is its an alignment problem. Some entrepreneur will likely invent a magic clamp that holds the chip in perfect registration to the PCB, at which point it'll be dirt simple to solder BGAs.
I donno where the "if you're a millimeter out, your chips are fried" stuff comes from because thats /.ed. I've done analog microwave RF work where that is actually true. That is not possible on a logic level board. "oh noes, /ce has been grounded, whatever shall we do?" Well just fix the solder bridge and stop whining. Its not like you just shorted out a 20 amp 24 volt power supply thru the bias/bypass network of a microwave FET amplifier, nothings going to blow up on a digital ckt.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
I still want 10 of them...
"I disapprove of what you say, but I will defend to the death your right to say it." - Evelyn Beatrice Hall, re Voltaire
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.
People have been doing BGA in toaster ovens for a while now. I'm not saying I'd try it with stuff this size, but it is doable. http://www.die4laser.com/toaster/index.html
Each processor would proceed sequentially as if it had been better for them not to rise against Saul.
And to think that only 30 years ago a resourceful fellow could fix a circuit board with a silver dollar, pliers, and a car battery. With today's electronics, MacGyver would be dead.
The only assumption I saw was that most folks would botch assembly due to the teeny smd tolerances.
So, anyone who does it successfully would achieve a rare accomplishment, through hard work, diligence, and skill.
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."
I thought the main reason they couldn't build the Raspberry Pi in the UK was there were prohibitive costs to importing the needed components whereas the completed device was taxed differently.
Isn't this the same problem?
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.)
I could mess up soldering a 0 gauge wire to a car battery terminal, but I should be free to do so and waste my own funds doing it!
Their business, their decision. Don't like it? Fine; design, manufacture, and market your own credit card sized PC kit, and/or don't purchase any Raspberry Pi products.
I swear, with all the real oppression going on in today's world, it's astounding the nonsense people come up with to bellyache about in the name of "freedom."
An enigma, wrapped in a riddle, shrouded in bacon and cheese
It would probably cost more to package the components for a kit than to assemble the thing anyway, so your kit would not only cost more, it would probably never work anyway.
Your reflow oven would need the correct temperature profile, you'd need a solder paste stencil, you'd also need fresh solder paste of the correct type - because it has an expiry date and should also be kept refrigerated.
The fact that they won't deliver in kit isn't news*, it's more interesting to know that they have HW-accelerated versions of MPEG4 and H.264 (and only those), and that all these libraries are closed source.
Furthermore, claims that they have the fastest mobile GPU are fluff: we only have the subjective word of someone who worked on it, not a neutral 3rd party, and it'll be caught up by someone else soon anyhow.
Finally, I'm going to advance that any complaints about the nvidia binary driver are going to be small fry compared to Broadcom's drivers.
*it's just not possible to hand-solder BGA packages. At best you'd need a reflow oven, and *that's* still tricky with the sizes involved here.
Misleading titles? Inflammatory blurbs? Keep in mind that Slashdot is a tabloid.
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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ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
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.
HTPCs mess with the signal in all kinds of ways (YUV->RGB conversion is forced, even if you select YUV, it converts to RGB then converts back)
RGB to YUV is lossless in both directions.
Give me Classic Slashdot or give me death!
http://www.raspberrypi.org/archives/592#comment-10077
Visit the
HTPCs mess with the signal in all kinds of ways (YUV->RGB conversion is forced, even if you select YUV, it converts to RGB then converts back)
RGB to YUV is lossless in both directions.
But you lose the overtones.
The chips are not available from digikey, only directly from broadcom, in large numbers.(tens of thousands)
Well unfortunately the Broadcom SoC used in this is only available to official Broadcom partners. So no, the typical person who wants to do this CAN'T acquire the parts.
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.
I hadn't the slightest objection to his spending his time planning massacres for the bourgeoisie... (P.G. Wodehouse)
It's not that hard to reflow parts. I do it all the time with a toaster oven; basically you turn it on to 200F for a couple of minutes to let the board's temperature equalize, then you crank it up to the maximum, and when it gets there, turn it off and crack open the door to let it cool down slowly.
The problem is that this only works with leaded solder. You need a hotter oven to reflow lead-free solder. But there's not really a good reason to use lead-free solder anyway, so I see it as a non-issue. It's mainly used because some stupid people are worried about kids eating it or something, causing dumb laws to be passed. Simple solution: don't eat your electronics. You don't eat drain cleaner (or let your kids eat it), yet drain cleaner is easily available and no one's banning that, so what's the problem with electronics?
You also don't absolutely need a paste stencil; there are kits available with paste in a syringe with needle; you just squirt a tiny amount onto each pad. Of course, this really doesn't work too well with BGA parts, only the larger-pitch parts and passives. BGA parts, however, shouldn't need any paste; they come with solder balls already installed on the bottom, so you just place them where they're supposed to go, and reflow. There's even reballing kits you can get; I think there was some big problem with Xboxes a while ago requiring this for many out-of-warranty units, and a small cottage industry sprang up with people reworking these boards at home, removing the chip, reballing it, and reflowing it in a toaster oven.
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?
I work at a place that has pick-and-place machines to manufacture our stuff. But we don't do BGA yet because we don't have the X-ray equipment to confirm that the BGA was soldered properly. Sure, you can do this in a toaster oven (it's somewhere on sparkfun.com), but it's not even for experts, it's for completely crazy people.
I have a lot of experience soldering small packages and would not even bother attempting a BGA.
This isn't just about "soldering small packages", this is about stuff where you can't even get physical access to the places that need to be soldered. I've soldered some 0.5mm QFP stuff (with an 0.4mm tip and a flux pen), but it's not fun.
tl;dr for TFA: This ain't Heathkit, and Heathkit never put surface-mount stuff in their kits.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
If you think it gets too much attention on Slashdot, don't read the article or post about it.
If you think it should be a kit, design a similar system and only sell it as a kit. The people behind the R. PI didn't just sit around and whine, they did something. Don't just complain about it.
If don't like the closed source drivers, then reverse engineer them yourself. Or get together with the people who want an kit and write their software. Do something beside bitching.
If you think that assembling a kit at this scale is easy, set up a web site that shows how it can be done. Sell a kit of supplies for the process. Don't just emit hot air.
You people act as if the motto of Slashdot was News for crybabies, Stuff that sucks
Why is Snark Required?
I put BGA's, LLP's, and SON's on boards by hand all the time. I use a hotplate that goes to 260C rather than a toaster oven because I can place it and then look at the edge with a boom-type microscope set at 45 degrees. With a BGA you can see slightly under the package to make sure the balls are on the pads; with an LLP or SON you can see the edges of the chip leads and make sure they're aligned with the pads. Check all four sides, because it's not uncommon to have one side lovely, the two adjacent sides slightly twisted, and the opposite side almost one whole pad off. If you're using leaded solder it'll tend to self-align, but you can't trust that. Bolting insulative material (we used old FR4 boards) to each side of the hotplate prevents you burning your hand from touching it by mistake and provides you a place to steady your hand while adjusting the rotation/placement with a dental pick. We place 0.5mm pitch BGA's (which we call microSMD's) this way on a regular basis, when our BGA rework station is busy or down.
AND! it is possible, although painful, to check continuity to the chip from the board, in many cases, without an x-ray. Check for a diode drop from each node to the substrate.
Nostalgia's not what it used to be.
Have you ever reflowed a BGA package that sits on top of another BGA package, with 0.3mm pitch? It wasn't stuck down a tiny vibration moving it in to your toaster oven could mis-align it.
This works for 'mundane' chips.
Not so much for ones that are either hard-to-use.
Yes, you may be able to get samples. But only if you qualify as a vendor likely to buy _large_ quantities.
http://www.ti.com/general/docs/wtbu/wtbuproductcontent.tsp?templateId=6123&navigationId=12494&contentId=4711&DCMP=WTBU&HQS=PlatformGuide+PR+wilink_4 - for example.
Contains the boilerplate 'This product is intended for high-volume wireless OEMs and ODMs and is not available through distributors. If your company meets this description, please contact your TI sales office.' - and they mean it.
This is very, very common for higher performance more difficult to integrate chips, or ones aimed at certain markets.
In short - they don't particularly care about small designers, only about ones likely to build 100000 of them in. It takes more or less the same amount of product support to support a vendor making 100, as a million. Support is expensive.
RGB to YUV is lossless in both directions.
Only if you're working in infinite-precision floating point. In the real world, this is a lossy conversion.