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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!!!
which are???
Please enlighten us mere mortals....
Laters Sol "Have you found the secrets of the universe? Asked Zebade "I'm sure I left them here somewhere"
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
Can i use these to power some anal vibrators?
Well, there was a video of a motor running with the PI. You could build a sex machine with it I guess.
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
Don't forget the reflow oven, so not only do you need superhuman skills, but you need a specialized tool that effectively nobody has.
Test your net with Netalyzr
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.
Correctly soldering BGA packages requires a reflow oven or a good heat gun with some solder paste. This is intimidating not only for customers with basic soldering skills, but even those who have extensive experience soldering other small SMT packages. Nevertheless, releasing the PCB as open hardware would allow people to fabricate and assemble their own boards, without placing an additional burden on the company.
I don't like the assumptions they're making.
Ditto! 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!
Home of The Suki Series
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.)
Go ahead. Buy one, take it apart and do a worse job putting it back together. Who's stopping you?
For many neat electronic devices, US law.
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.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
This article also confirms that the Raspberry Pi will likely be worthless as a media streaming device - at least for those of us who care about video quality.
It is now official that only H.264 (and MPEG-4) will be supported for hardware decoding. That means that playback of ripped Blu-rays that use VC-1 and MPEG-2 (not an inconsiderable number) is impossible, since the weak ARM CPU will almost certainly not be able to decode them in real-time at 1080p.
I'm sure the Pi will work fine for people who play back transcoded crap downloaded from TPB, but for anyone who actually cares about video quality, the lack of these essential codecs is a death sentence. We can only hope that at some point in the future a different (even if more expensive) model will ship with them enabled.
It's really a shame that there is currently no open-source-friendly SoC platform that supports HD video decoding and HDMI 1.3 audio bitstreaming in all its forms. 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) so SoCs are really all that can provide decent quality. And the firmware on commercial media streamers is almost all crap.
1. "Raspberry Pi
An ARM GNU/Linux box for $25. "
2. "You could build a sex machine with it I guess."
3. "ARM inside" logo
4. ?
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.
They might as well include one of these in the deal too, for people who like to do pointless and unnecessary things:
http://www.flickr.com/photos/peterme/3428170/
http://www.raspberrypi.org/archives/592#comment-10077
Visit the
Since it's an open design, the few who REALLY want to do that even though it will cost more than a pre-built unit (due to packaging etc) can probably get together and order the needed parts.
As it is, they appear to be doing a find job getting the pre-assembled form designed and built now, they likely have their hands full.
whenver I see a chip upside down, dead-bug style, and wires coming out going to the board below, I grin. I've been there, so I can grin...
--
"It is now safe to switch off your computer."
#firstworldproblems
#whitewhine
Hail Eris, full of mischief...
E pluribus sanguinem
44pin Quad Flat Pack are trivial to remove and replace with the right tools - which basically means a hot air gun with the small nozzle. A couple of weeks ago I removed and replaced two 144 pin quad flat pack devices with 0.6mm pitch legs in about 10 mins. It isn't something I want to do for production boards but it is fine for the development boards I was using.
Screen printing solder using solder masks + ovens are easily within the hobbiest market now. You can get a custom PCB + solder stencil made for £40 (100mm^2) and I use a £50 oven to melt the solder. Gives good results too (though I still do the sub 1mm pitch pins by hand as I get too many shorts otherwise).
I've not attempted BGAs as I could see that the success rate might not be too high.
wot no sig
Did you see the illustration in the article? The two main chip packages are pictured on the end of a guy's index finger. Sure, people like to difficult things, but come on! If you're not using the proper ($20,000 +) machine tools you're rate of failure is going to be +/- 90%... just buy the production package, for your own sanity man.
Python: 'And then suddenly you have a language which says "we're all stuck with whatever the whiniest coder wants".'
Tell you what, I'll buy one, desolder all the chips, put it all in a bag and ship it to you for $50. Then you can have fun putting it back together. :)
We can have competition: how many times you can desolder/solder the yoke before it stops to work? ... and don't tell me what are you are doing with the other one.
Extra points if you use only one hand
You can't actually buy the components involved in small (under 10000) quantities.
In addition, desoldering and attempting to re-ball BGAs is not a good idea.
I'm one of the ones that requested a 'kit' - of the major components - I don't care about the tiny components, those are easy to source.
Why?
Several reasons.
Amongst them:
Because I can (maybe).
Because the r-pi is annoyingly large for some use-cases.
Because being able to trim the design to have just the required bits on can be useful.
Fundamentally - this is about education. Not software, but hardware education.
Fostering a community of interested hardware engineers.
It's a lot easier for many people if in addition to the problems of actually physically constructing the board, (not the actual making the PCB, only insane people would try that), they don't have to do any significant software work to get the board up and working.
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)
They have a limited initial run of devices, half of which will be defective in some way, and the returns will kill them off before they ever get a chance to ship in volume. 3 months and we'll be reading about how it all went wrong, and the lessons they learned.
If you were blocking sigs, you wouldn't have to read this.
Everything is sold in kit form. Just packaged in a convenient form for kit testing. Just put it in your toaster oven and the components fall right back apart for your assembly challenge. I've soldered some of these tiny components before. You'll want to lay off the coffee for a few days prior.
Help stamp out iliturcy.
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.
You can't actually buy the components involved in small (under 10000) quantities.
Citation needed.
You can get prototype quantities of any electronic part out there. It might be expensive, though sometimes you can get mfgrs to send you samples for free, but how do you think design engineers test their designs?
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?
That's just not true. It's relatively trivial to solder even BGA parts with an oven (and a $50 "toaster oven" qualifies. Just don't use the same oven for food...)
Here's how I do it:
Handling these tiny parts (0603 / 0.5mm BGA is as low as I go) is trivial if you get a pair of these. They look as dorky as you could ever hope to not appear, but they really (*really*) work well. At going-on 45 my vision just isn't up to placing 0805 / 0603 by hand any more, but these things really help line things up perfectly.
Also, get non-metallic tweezers, and a well-lit area :)
Simon
Physicists get Hadrons!
Double extra points if you're wanking with that other hand.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
> Since it's an open design
Nope. Show me the link to the design docs.
And the SoC? Don't even think of asking. The documents are not for distribution.
Yes, it would be trivial to solder on normally.
Production had the pin order flipped, so the chip had to be soldered upside down.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
I have been pushing mine into the slot in my computer box thingie, you know the one just below that opening cupholder.
I got to the chocolate box before you, that's why the hard ones have teeth marks.
Actually, I prefer gooseberry Pi.
"I've been throwing my money at the screen for months and NOTHING'S HAPPENING!!!"
Patience. Soon we'll be able to say "Stick a fork in it. The Pi's done."
But. But.
I AM a pick and place robot, you insensitive clod!
Yes, it would be trivial to solder on normally.
Production had the pin order flipped, so the chip had to be soldered upside down.
Oh yeah? Reminds me of when I used to solder QF44 PICs upside down, uphill, in the snow, both ways. :)
Seriously, some people are just hard to impress and feel the need to one-up no matter what.
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?
Here's how I do it:
Order the damn Raspberry PI board.
I win!
Faster! Faster! Faster would be better!
The chips are not available from digikey, only directly from broadcom, in large numbers.(tens of thousands)
Well, given the fact that you'll waste a few getting your technique up, probably not such a big issue. Besides, once you get them put together, you'll want to give one to everyone on your Christmas list!
Faster! Faster! Faster would be better!
Since the raspberry pi itself is pretty cheap, they could just desolder one off a working board.
[sigh] I have no intention of getting a Raspberry PI board. I was talking in general terms.
Enjoy your "win"...
Simon.
Physicists get Hadrons!
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.
The chips are rated for one thermal cycle.
Doing multiple ones is beyond the manufacturers recommendations.
In addition, you have to replace the 'balls' on the BGA after you desolder it, and you end up with a part that's - probably - going to work.
It will never be as likely to solder on without errors as the original part was.
Well I'll give him that it's an interesting challenge akin to building a ship in a bottle or painting on a grain of rice. I might give it a go, in a year or two if I have a few spares of this laying around and that much spare time. But at $35, it's cheaper than a kit would be so I would depopulate the components myself. After taking very hi rez photos of course. But the smaller components are really tiny. Just a faint breath will blow them away. And at this scale everything is incredibly sticky so it can be frustrating.
Help stamp out iliturcy.
I see. Thanks for the link. I haven't had to work with chips like that.
You can't get samples of this chip unless you can commit to buy at least 1 million chips a year. Broadcom won't even let you see the datasheet.
The only reason this thing is happening is that at least one of the devs on this works for Broadcom and is smuggling the chips out in his lunchbox~
Ah, you're right. Reballing can be annoying but the people in China do it all the time, somewhat reliably. No telling what effect the PoP will have though.
Well, lets see, the gerbers, schematics and BOM are all out there. Were you hoping to fab the SOC yourself in the kitchen from sand too?
This is totally incorrect. You only need an oven, stencil, and fresh solder paste if you're doing large quantities of boards. Doing small quantities of boards by hand is fairly easy with some practice. All you need is a syringe with SP, a basic ($100) soldering station, a cheap ($100) hot air rework station, some solder wick, and a flux pen and you can solder just about anything.
I can comfortably and reliably solder parts down to 0.5mm pitch using these tools and I do it all the time with great success. I actually think it is easier than stuffing through-hole parts and generally try to stick with SMDs in my designs. And the smaller the better.
I have a big ass cartridge of Kester No-Clean 63/37 paste that has been sitting in the bottom of my refrigerator for the past year and a half. I fill syringes with it and it still worked just fine the other day. I often need to touch up some of the finer pitched parts by hand, but that isn't much of a problem in small quantities. Having to hand solder a few thousand boards wouldn't be acceptable, and that's where you need that oven, stencil, and fresh SP.
Would I want a kit of the Pi? Probably not. While I enjoy stuffing PCBs and find it quite relaxing, a good chunk of that enjoyment comes from it being my own design and having to do my own programming and troubleshooting to get it to work. The point is I think the suggestion that SMD assembly is outside the reach of hobbyists is total ignorant bullshit.
One of the main problems at the moment I can see is the lack of docs
and I'm not talking about the GPU, but the GPIO pins for SPI / A/D etc
it's pretty clear looking at the forums that they're not targeting it at the hobbyist for interfacing, but instead at just being used as a basic terminal in 3rd world countries
Reading through the forums the SoC has no datasheets available for it for interfacing
the SoC can't be purchased separately outside of the site (less of an issue given the soldering problems)
They've suggested that there will be docs later on for the GPIO's but that it's going to come much later on
So if your planning to use it as something other than a cut down PC your out of luck
A shame really as I wanted something like this for the .Net Micro Framework as a sort of more advanced version of the netduino (64K Ram vs 256Mb Arm11)
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?
Leaded solder is illegal for use in consumer electronics in the EU (still available for hobbyists though) largely because of the pollution involved in recycling the stuff. Which is ironic, as it's largely responsible for reducing the lifespan of electronic goods to about 3 years before the solder gets too brittle and cracks, and the massive increase in electronic waste this has caused.
Seriously - what computer does come as a component-level kit? Yes, the Altair did, but that was a long time ago. Does anyone really sell a bare motherboard??
Exactly. I have read there's some applications where it's actually better because of the higher heat necessary (i.e. high-heat applications), and that some formulations of lead-free solder don't have the embrittlement problem as bad. The other problem is that, without lead, the lead-free solder grows "tin whiskers", which cause a lot of failures. These can be mitigated though by using a conformal coating, but that adds a lot of cost and also makes repairs difficult or impossible. Most consumer electronics don't worry about this, though, because it takes several years for problems to occur, and by that time the warranty's over, so they expect you to pitch it and buy a new one. So much for reducing waste....
If they want to deal with the pollution involved in recycling, the answer is simple: get people to properly dispose of electronics (like we do with other recyclables), and then develop a recycling process which safely handles the materials. There's a lot of valuable metals in electronics; it shouldn't be that hard to grind them up and melt them down, separating the gold, lead, tin, and copper out. In a properly-designed facility sealed from the atmosphere, this should be perfectly safe and clean.
Freedom? Why do the most idiotic Americans always bring up liberty in every goddamn discussion?
Because so many of our ancestors were enslaved and murdered by the ancestors of self-righteous Europeans, especially when American ancestors tried to get a few liberties.
Jesus was all right but his disciples were thick and ordinary. -John Lennon
Ok... Do it by hand with a Package-on-Package configuration. Best of luck.
The local Techshop just got a reflow machine; also a reballer.
It also has an Acuna Lathe with full CNC, you know, in case you need to carve a full size Darth Vader mask out of aluminum for some reason.
You join for a monthly fee, and then play with things that can cause you to lose fingers to you hearts content.
-- Terry
They won't leave a lasting impact. (Score:-1)
by Anonymous Coward on Friday December 23, @12:34AM (#38468480)
as a short penis
thrusting inside receptive anus
come raspberry pi
Oh, Come on! Trepanning can still be needed and very much to the point.
Modern medical practices
Trepanationis a treatment used for epidural and subdural hematomas, and for surgical access for certain other neurosurgical procedures, such as intracranial pressure monitoring. Modern surgeons generally use the term craniotomy for this procedure. The removed piece of skull is typically replaced as soon as possible. If the bone is not replaced, then the procedure is considered a craniectomy. Trepanation instruments are now available with diamond coated rims (Diamond Bone Cutting System), which are less traumatic than the classical trephines with sharp teeth. They are smooth to soft tissues and cut only bone.
w00t.
"No fear. No envy. No meanness." Liam Clancy
I tried to reflow an Xbox once, using the electric skillet and heat gun method. Things were looking good, and then I heard the world's quietest -clink- as a tiny, flea-sized capacitor fell off of the bottom of the board I was working on.
I've got a steady hand, but there was no way I was ever going to get that cap reinstalled without it disappearing in a puff of smoke.
How to successfully and predictably accomplish the task of melting solder on only one side of a board with components on both sides is a mystery to me.
Kid-proof tablet..
nt
Running with Linux for over 20 years!
SMD capacitors are pretty to solder with a proper iron and conical tip. A lot easier than most multipin packages (esp. the fine-pitch ones).
For double-sided boards, it's not that hard. You solder the bottom side first, and then as long as all the components on the bottom side are small, the surface tension of the solder holds them on when you solder the top side. The board can't be jostled, however, as they can fall off. For larger components, you have to use adhesive to hold them on; the large-volume places have a machine that places a drop of adhesive under each chip or other large component to hold it in place when it's inverted.
I'd say the electric skillet method sounds like the wrong method to use for double-sided boards, since the idea is that you're relying on surface contact between the board and the skillet to heat up the board, and that isn't possible if there's components already on the backside; I've heard of people doing them in toaster ovens, by clipping binder clips to each side to hold the board up off the rack and not touching anything while it's hot.
No, it doesn't. It says "oh, there's some closed blobs in there, lolz". Seriously, why do vendors feel like they have to get shitty about having proper open drivers?
Well the answer is simple, if you want those chips and would have the skills to actually assemble the thing desoldering it shouldn't be a problem. Oh and for those that do like to DIY, may i make a suggestion? Try BGMicro they have good prices and great service. I have an engineering buddy that does a lot of robotics design work for the local college and he's been going there for years, has nothing but good things to say about them. be sure to sign up for the emails as they have some pretty good email only sales.
ACs don't waste your time replying, your posts are never seen by me.
The board pattern and parts list is publicly available, if you really want to impress us.
The point is I think the suggestion that SMD assembly is outside the reach of hobbyists is total ignorant bullshit.
I think the point is that reliably mounting such fine pitched SMD parts (stacked no less) work is beyond the reach of a significant portion of their customers. Certainly enough that they made the safe decision to just pre-mount them. Otherwise, they'd be knee deep in people calling to complain that their board didn't work after they eyeballed the placement and reflowed them with a hairdryer.
Considering you can buy a hot air soldering system for little over $100 on eBay, I call BS.
"Politicians and diapers must be changed often, and for the same reason."
i just don't understand this. it's not even an electronics project; it's sticking two totally arcane black boxes together. there's no particular logic or thinking or knowledge involved beyond the chip layout. it's just a tedious process involving luck, dexterity, and a very specialized skill that doesn't generalize much.
why the hell would anyone want to do this? it's certainly not curiosity, since that's generally about not doing things which a fucking robot can do 1000x better.
if you wanted to start a cottage industry repairing the sure-to-be ubiquitous raspberry pis (lol), that's a reason i guess, but you can just wait until it happens and you'll have plenty of junked parts to practice on.
"They were pure niggers." – Noam Chomsky
Well, apparently the surface tension trick didn't work, because it fell off anyway. :) I kind of figured that being even slightly jostled would ruin the process, so I worked and stepped lightly, and instructed others in the house to stay away.
I've got a proper iron with a real thermostat and a nice sharp tip, but I could barely even see the capacitor: When I said it was flea-sized I wasn't exaggerating. I've dealt a bit with SMD parts and had fine luck with them, but this cap was perhaps 1/15th the size that I'm comfortable handling.
The skillet method involves using nuts and bolts in the mounting holes of the board to act as spacers, and targeted application of a heat gun topside. It'd probably work better with a good infrared thermometer, which I don't have.
Kid-proof tablet..
with the automated assembly vs kit form, I would guess that a kit would be 3 x more, because of all of the manual handling required to get kits together. Electronics like this has really moved on from kits.
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huh? how?
"They were pure niggers." – Noam Chomsky
Try touching up one of the 240 odd balls on the bottom of the broadcom bga package, or the 100 odd balls on the sdram that sits on top of it. They're 0.3mm by the way, not 0.5mm.
Well, you seem to be going back to that at the moment.
So, anyone who does it successfully would achieve a rare accomplishment, through hard work, diligence, and skill.
Call me crazy but the type of person who could achieve soldering of a BGA package would unlikely feel a sense of accomplishment from building a kit, and likely has the technical know how to almost make a RaspberryPi from scratch.
Reflow soldering involves heating the components much hotter than they like to be even when powered off.
Yeah, whenever you turn off a system with a processor inside it, all of the electrons have to flow back out of the processor, and over the next hour or two it can heat up even hotter than when the processor was operating.
Easiest way to deal with that is that if you have a 2-prong device and it's not one of those polarized plugs, you can just pull it out of the outlet, flip it around, and plug it back in the other way for an hour or two. That will send the electrons flowing the other direction through the circuit (and the processor), and then you'll have a much smaller cool-down time.
coding is life
Well, you seem to be going back to that at the moment.
Not even close, we're trading European enslavement for Chinese enslavement.
Jesus was all right but his disciples were thick and ordinary. -John Lennon
You are being enslaved by your own government - forget about anyone else.
Pre-fab sand!?
I am perfectly capable of putting together my own molecules, thank you very much!
please explain, The American Revolution, the US basically gave up liberties, the British rulers where far more tolerant and fairer tax then the immediate US governmental systems that followed.Fundamentally the US revolution was Brits fighting Brits for a system that was less fair then the existing system, very peculiar.
I'm sure they will release documentation in good time, but even before that it would be easy to add additional custom hardware interfaces through USB in the form of Arduino or other USB supporting hardware platforms.
Also the idea behind the project is not to be a cheap terminal for 3rd world countries (tho it would serve this purpose very well) but as an ultra cheap programmable computer for English school children to encourage more programming in IT lessons and bedroom coding like in the days of the ZX spectrum and C64.
Complain to Broadcom, as they're the ones forcing the use of these, not the Raspberry Pi guys.
Name a single low-cost micro-controller system that is sold in kit form with stacked BGA components.
You clearly have no idea what you're talking about. If your ignorance isn't willful, pick up a child's history book- nobody here has the time to start from scratch with you.
He's trying to move the conversation off-topic by citing DMCA. This isn't about rooting an iDoohickey, or reverse engineering a network protocol. DMCA doesn't apply here since the point was about unsoldering components, not breaking an actual security mechanism.
With a properly designed prototyping board you can solder some kinds of BGA parts by hand.
http://www.schmartboard.com/index.asp?page=products_bga
This is good for experimenting with new parts and engineers use these kinds of tools to bootstrap new hardware designs by saving upfront work laying out a prototype board. Not the kind of thing someone who likes to build 'Heathkits' might want to do though.
Never had a problem with the 515 pin VFBGA on the OMAP3530, that dinky Broadcom package looks easy in comparison. BGAs and POPs aren't all that hard, they're actually fairly easy and never need any kind of touching up since they provide their own solder. Just flux and go.
And where did you read it was 0.3mm? From the picture it looks like 0.5mm on the POP side and 0.65mm on the board side to me. Can't find a datasheet though. Doesn't matter, my 0.5mm limit is with regard to comfortably soldering individual exposed leads which isn't a concern with BGAs.
Again, my only point is that people can assemble these types of components, and it drives me nuts when ass holes like yourself who have clearly never tried it proclaim that it is impossible. Please, stop speaking out of your ass.
And just to be clear, I am not suggesting the Raspberry Pi should be sold as a kit - if they don't want to deal with that headache, then that is perfectly reasonable and I wouldn't buy one anyway.
I agree entirely. Doing your own toaster oven reflowing is OK if you don't have an alternative (i.e., you're making your own custom PCBs, and having them assembled by another company is prohibitively expensive because of the low volumes), but if you can get the board pre-made cheaply with robotic precision, why on earth would you want to do it by hand? It's kind of like digging ditches by hand vs. using a Ditch-witch.
ah, yes. thanks.
"They were pure niggers." – Noam Chomsky
Will you sell a self-assembly kit?
No. It would be too expensive for us to provide kits alongside finished boards, which would mean introducing another step in manufacturing; and a kit would be impossible to hand solder. We use special equipment (robots!) to solder on the BGA package and other tiny components.
All those assholes are dead and rotted. What they did may have historical implications today, but other than that it doesn't fucking matter. Get your own life and let the dead rest in peace.
That, or come up with a single good reason to bring up liberty in a discussion where it otherwise clearly doesn't belong.
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."
Yes, some people even spend their time whining about other people whining -- can you believe that!
I just heard that the Raspberry Pi website CSS has been tweaked.
A new element "checkout_button" has been referenced in the CSS.
Rumours that this is an indication that the Pi will launch soon have reached fever pitch!!!
It's like iLaunch hysteria, but for techies! Yey!
RS