#qi-hardware IRC log for Wednesday, 2011-04-13

qi-bot[commit] Maarten ter Huurne: Added missing #include. http://qi-hw.com/p/gmenu2x/8995a3c01:18
qi-bot[commit] Maarten ter Huurne: Added missing #include. http://qi-hw.com/p/gmenu2x/34a3d5501:18
qi-bot[commit] Maarten ter Huurne: Merge remote branch 'origin/master' http://qi-hw.com/p/gmenu2x/f9db1fb01:18
qi-bot[commit] Maarten ter Huurne: Cleaned up link flags. http://qi-hw.com/p/gmenu2x/23042f301:42
Action: kristianpaul going home01:43
qi-bot[commit] Maarten ter Huurne: Cleaned up link flags. http://qi-hw.com/p/gmenu2x/c22cc4d01:44
qi-bot[commit] Werner Almesberger: atrf-path: added min/max values and corrected averaging algorithm http://qi-hw.com/p/ben-wpan/b159e0001:59
qi-bot[commit] Werner Almesberger: atrf-path: generalized sweep interface (for reuse) http://qi-hw.com/p/ben-wpan/6df648701:59
qi-bot[commit] Werner Almesberger: - atrf-rssi.c (gui): moved system-dependent definition to gui.h http://qi-hw.com/p/ben-wpan/2967f9901:59
qi-bot[commit] Werner Almesberger: atrf-path: added basic graphical output http://qi-hw.com/p/ben-wpan/0a4091001:59
wpwrakah ... and "xxx" from a few commits ago should have been a fixup. hmm ... to change history or not, this is the question ... i guess i'll just apply Sloth's Razor :)02:02
rjeffrieswpwrak is "sloth" the son of Occam?02:28
tuxbrainHi dudes :)12:45
wpwrakwhoa, the return of tuxbrain ! ;-)12:49
wpwraktuxbrain: have the fabs reached a conclusion regarding the hole for the connector ?12:51
tuxbrainWpwrak yes there in no problem with no hole :)12:52
wpwraktuxbrain: *hmm* so how will they solder the connector ? do they realize that the connector goes below the edge of the board ?12:55
wpwraktuxbrain: so they either have to remove (cut) the board there, depanelize, or solder the connector with a different process than the main SMT reflow12:56
tuxbrainI will aks but no price rice no delays so watever is fine for me se you later12:57
wolfspra1lwpwrak: let's hope that that won't end in painful realizations for tuxbrain later...13:14
wolfspra1lI'm not following every detail, but everybody needs to be realistic how much a whole company can get done for 100 USD or 200 USD margin nowadays, if asking a plumber to come fix a water leak costs a similar amount...13:15
wolfspra1lso they may just plow through the process, tuxbrain owns the yield :-)13:15
wpwrakwolfspra1l: (painful realizations) yeah, it has that ring ...13:16
wolfspra1lfrom following a bit between wpwrak and Adam I'm not entirely convinced yet... :-)13:16
wolfspra1lmost of them time when you think through such a process, and you realize "hey, that step at that point won't work because...", then everybody else better turn on their brain as well :-)13:16
wpwrakwolfspra1l: i kinda wonder who actually "owns" the yield. i haven't seen this explicitly stated anywhere.13:17
wolfspra1lthe assumption that the other side has 'already thought about everything' is quite naive13:17
wolfspra1lthat's pretty clear to me ;-)13:17
wolfspra1ltuxbrain is the boss, tuxbrain owns everything13:17
wpwrakwolfspra1l: (trusting the other side) i think our experience at openmoko has thoroughly cured us of hat, hasn't it ? ;-)13:17
wolfspra1lalso we have to be realistic how much thought can actually go into it (=little)13:18
wolfspra1lthey don't have 2-3 guys looking at this for hours, which is what we do here13:18
wolfspra1lbecause that alone would quickly cost 500-1000 USD13:19
wpwrak(ownership) it seems that the smt fab wants a bit of ownership, too. e.g., they do sourcing, which implies that they also do yield estimates on the component count (maybe not the at-end-of-smt yield but other component loss in the process)13:19
wolfspra1lI highly doubt that13:19
wolfspra1lin fact if they do sourcing, there may be lots of nasty surprises13:19
wolfspra1liqc is highly economical (=optimized), and to optimize it for your product is again not something they have many resources for13:20
wpwrakheh ;-)13:20
wolfspra1lso the yield of components may vary (very much) depending on how and where they are used exactly13:20
wpwrakluckily, the boards are pretty simple. so there's only so much they can do wrong :)13:20
wolfspra1lthat is all impossible for them to 'get right', because they don't have enough time (enough eyes) for it13:20
wolfspra1lall of this will end up on tuxbrain's side later13:21
wolfspra1lwhereas if you 'know everything', you can source with a lot of knowledge, let's say the run is 50, but some components you source 60, some 55, some 70, etc.13:21
wolfspra1l"because you know"13:21
wpwrakwell, some parameters also come from the fab. that makes it a bit more complicated. e.g., what presentation exactly they need for their machines.13:22
wpwrak(and at what point they just don't use machines)13:22
wolfspra1lthe only thing I'm worried is that tuxbrain may just not imagine that some of his suppliers overlook something that will later turn into a big problem, which of course he will own13:23
wpwrakwell, we'll see how it goes. i don't like the idea of outsourcing sourcing either, but if tuxbrain is happier that way ... :)13:23
wolfspra1lwhich isn't even their fault, it's just difficult to get all these parties to do 'just the right things', given the small margins and small amounts of money13:23
wolfspra1lwpwrak: tuxbrain thinks "sourcing is taken care of"13:24
wpwraklittle thinks ... like baking ;-)13:24
wolfspra1lwhich is a good theory13:24
wpwrakmy expectation is that it'll work without excessive pain. the quantity is small and if anything goes horribly wrong, you can always stop and look for a workaround13:26
wpwrakthen, in the next iteration, we can burden tuxbrain with some more details ;-)13:27
wpwrakregarding sourcing, none of the components should be overly difficult. some of them aren't stocked by all major distributors, but you always have a number of choices. so worst case there would be a delay of a week to order something, plus preparation-for-the-machine overhead13:29
wpwrakwhat should help is that they're all local, so he can go there and watch what happens. now he just needs to know what to look for :)13:32
wolfspra1lhe absolutely should go to the run13:33
wolfspra1lwpwrak: my concern about sourcing is not so much the technicality of where/when/how many to order, but the iqc13:34
wolfspra1lwith a software mind, there is no iqc, and it doesn't have much value13:34
wolfspra1lbut with a hardware (analog) mind, you will soon realize _EVERYTHING_ has tolerances, everything is a matter of spending just the right amount of time to check for the right things that matter in your application13:34
wolfspra1land that is hard13:35
wpwrakthere probably isn't much we can do about iqc per se13:36
wpwrakthere are a few things you can detect in end-of-smt testing, though13:36
wolfspra1lno but if you outsource sourcing, that's the thing tuxbrain should keep his eyes on13:36
wolfspra1lbecause that's where knowledge of the particular board matters, and whoever you outsourced sourcing to may not know it as well as you do13:37
asmanuris this possible to solve the problem with suspending without kernel hacking ?13:37
asmanurit has been suggested to wakup automatically the nanonote but can't find any ressources about it13:37
wpwrakwolfspra1l: hmm, but are you talking about faulty components or replacements with diverging specifications ?13:37
wolfspra1lI'm talking about no 2 components being exactly the same.13:38
wpwrakasmanur: larsc would be your expert for this13:38
wolfspra1lsourcing always has iqc13:38
wolfspra1lbut if you outsource it you create a dangerous potential knowledge leak13:38
wolfspra1ltuxbrain could ask them to go over the components and let them tell him what iqc they are planning13:39
asmanurwpwrak: yeah..i've read some logs but only saw vague methods :-(13:39
wolfspra1lthen they will tell him one by one "here we do this, here we only check label, here we check that"13:39
wpwrakwolfspra1l: (exactly the same) but tolerances are a design issue. only components outside the tolerance range are an iqc issue.13:39
wolfspra1land tuxbrain can match that against his knowledge of the board (if he can)13:39
wpwrakwolfspra1l: well, unless you buy with larger tolerances you need and then do the filtering yourself. but we don't want to go there ;-)13:39
wolfspra1lnah. sourcing (components) are not binary13:40
wolfspra1lthe vendor may say 'sorry' and take them back13:40
wolfspra1lbut whether it costs you 10 USD to get to the 'sorry' state, or 1000 USD, that's your problem :-)13:40
wpwrakwolfspra1l: yes, you can get a bad batch13:40
wolfspra1lnot just batch, also individual ones13:40
wolfspra1ltuxbrain will find out, the more runs the more he will find out :-)13:41
wolfspra1lit's all about economics13:41
wolfspra1lin hardware that's pretty painful because you just have no time to test 'everything'13:41
wolfspra1lbecause each individual component is so damned cheap13:41
wolfspra1land those stingy customers still want to slice off the last .1 cent13:41
wpwrakwolfspra1l: i don't think you can spot individual bad components efficiently. they come out of the tape at the smt machine and the smt machine doesn't do iqc ...13:42
wolfspra1lmy only point is (it's about process): if you outsource sourcing, watch iqc13:42
wolfspra1lno way, I talk about all components. something like the USB connector can, or cannot, be iqc'ed in many ways13:43
wolfspra1lagain: when you outsource sourcing, watch iqc13:43
wolfspra1lthey do not know your board13:43
wolfspra1lor at least not as well as you do13:43
wolfspra1llater you will say "man, why didn't you see this?" but alas, they didn't...13:43
wpwrakwolfspra1l: i'm still a bit confused about what exactly you mean. i understand taking a few samples from a batch and analyzing end-of-smt failures, but the potential for the checking of individual components seems to be limited. would you have some specific example(s) ?13:45
wpwrakwolfspra1l: (checking batches) well, and checking that this is indeed the right component. small detail :)13:45
wolfspra1llast m1 run we had a problem with lifted pins13:46
wpwrakand that was a sourcing/supplier problem ?13:47
wolfspra1lprocess problem13:47
wolfspra1lwe even did the sourcing, we just forgot to iqc lifted pins13:48
wpwrakalright. that's the ones you can catch at the end. run one board, see what happens. rinse and repeat.13:48
wolfspra1lthe thing is that manufacturing is about economics, not about correctness13:49
wolfspra1leverybody follows that13:49
wolfspra1lso the reaction "they are so stupid" is just stupid in itself13:49
wpwrak(iqc lifted pins) you mean the chip package was deformed ?13:49
wolfspra1lthey are not stupid, they operated with zero knowledge, on purpose to keep the costs low13:49
wolfspra1lactually the pins have tolerances already, from the datasheet13:50
wolfspra1lbut parts for a small run may come from different parties, some free samples, some from another run somewhere13:50
wolfspra1lthen it gets messy13:50
wpwrak(zero knowledge) i think the guys in spain know at least some things. they made some useful remarks and suggestions.13:50
wolfspra1ljust think about it - these things are so cheap, just pennies13:50
wolfspra1lif you would be a component vendor, you know you have to cut your costs as aggressively as possible13:51
wolfspra1lyou can take those penny items back13:51
wolfspra1lbut what damage does a 'bad' component cause to your customer?13:51
wolfspra1lis it 1 USD, or 100 USD or 1000 USD?13:51
wolfspra1lyou don't know!13:51
wolfspra1lit depends on them13:51
wpwrak(pins) okay, but as long as they're within spec, it's no longer an iqc issue.13:51
wolfspra1land their process, and how everybody makes sure that the right things are checked13:51
wolfspra1lsourcing ... iqc ... smt13:51
wolfspra1lI mean the iqc after sourcing and before smt13:52
wolfspra1lso it's already product-specific iqc13:52
wpwrakthe customers will also remember whom they to thank for for their losses13:52
wolfspra1lthey will go back to the cheapest supplier13:52
wolfspra1land see whether they can catch it in their iqc next time13:52
wolfspra1lmy point was that the component vendor also is no messiah13:52
wpwrakdepends. as i said, something are virtually impossible to catch.13:52
wolfspra1lthey cannot do and see everything13:52
wolfspra1ljust remember, it's not sourcing ... smt13:53
wolfspra1lit's sourcing ... iqc ... smt13:53
wpwrake.g., if you get a 10% tolerance cap that's 50% off. you'll never catch that one.13:53
wolfspra1land if you outsource sourcing, you have to be a bit careful about that13:53
wolfspra1ltuxbrain should ask them to walk him through the iqc steps13:53
wolfspra1lit's just a few components anyway13:53
wolfspra1lthis is valuable information that should be communicated13:54
wolfspra1lif it is not, it may be the source of surprises later13:54
wolfspra1lthat's my only point, I rest my case :-)13:55
wpwrakmaybe you could post what things to look for in those iqc steps ? my expectation would be: 1) visual inspection of the general condition of the shipment. 2) checking the label(s). 3) with luck, for unmarked components (caps, etc.), pick one and measure it (to make sure they didn't send you the 1 NF reel where you wanted the 1 UF reel)13:56
wpwrakfor larger samples, you'd already need bigger volume. for testing more sophisticated components, you need a dedicated process, which nobody has.13:57
wpwrak(nobody) that is, none of use nor the smt fab. if we'd make a few million boards, it would be worth developing one.13:58
wpwrakother things to look for would be moisture sensitivity, baking requirements, reflow profiles.13:59
wpwrakbut that's already past IQC13:59
wpwrakregarding mechanical issues, i expect that the usb connector will be more fun, but that's on the process side. and yes, that one wants watching. they may also mis-rotate some components. happens all the time. all but one can be checked visually. you can also see the led's orientation, but it's not so easy. but an ohmmeter will do the trick :)14:03
wolfspra1lyes correct, roughly those things14:10
wolfspra1lcalling it a day, reading backlog tomorrow... n814:10
qi-bot[commit] Werner Almesberger: tools/atrf-path/gui.c: temporarily added code for sweep time measurements http://qi-hw.com/p/ben-wpan/6efe37417:24
qi-bot[commit] Werner Almesberger: tools/lib/cwtest.c (cw_test_end): try "quick reset" on AT86RF231 http://qi-hw.com/p/ben-wpan/4244af217:24
qi-bot[commit] Werner Almesberger: tools/atrf-path/gui.c (gui): added pulsating disc as progress/status indicator http://qi-hw.com/p/ben-wpan/cee029617:24
qi-bot[commit] Werner Almesberger: atrf-path: the GUI is now activated with -g; also changed arguments in GUI mode http://qi-hw.com/p/ben-wpan/436c9fa17:24
qi-bot[commit] Werner Almesberger: atrf-path/atrf-path.c: initialize the receiver only once, not for each sweep http://qi-hw.com/p/ben-wpan/5f153ca17:24
qi-bot[commit] Werner Almesberger: libatrf: cw test mode can now be resumed, with lower overhead (231 only) http://qi-hw.com/p/ben-wpan/16a48d617:24
qi-bot[commit] Werner Almesberger: atrf-path.c: moved tx init out of sample loop (breaks 230 support) http://qi-hw.com/p/ben-wpan/e3463ef17:24
qi-bot[commit] Werner Almesberger: atrf-path: sweep offsets separately, so that the we can reuse the cw setup http://qi-hw.com/p/ben-wpan/2c1cb7117:24
qi-bot[commit] Werner Almesberger: atrf-path.c (usage): list common args only once, not in each synopsis http://qi-hw.com/p/ben-wpan/d263ffc17:24
qi-bot[commit] Werner Almesberger: atrf-path.c (do_half_sweep, do_sweep): don't duplicate the loop - use a function http://qi-hw.com/p/ben-wpan/598582c17:24
qi-bot[commit] Werner Almesberger: atrf-path: new option -T to sweep only one offset http://qi-hw.com/p/ben-wpan/e2a9c9d17:24
qi-bot[commit] Werner Almesberger: atrf-path.c: do cw test setup only once if sweeping a single offset http://qi-hw.com/p/ben-wpan/a7d9dfd17:24
kristianpaulI'm back !17:44
wpwrakkristianpaul: back from ... ? :)18:11
kristianpaulwpwrak: medellin :-)18:12
wpwrakaha ! was it interesting ?18:14
kristianpaulmet lot of people18:14
kristianpaulbrazil, argentina, france, mexico, espaƱa..18:15
kristianpaulnot too much hardware related projects, but "el movimiento sin satelite" is enought for me :-)18:17
wpwrakwhat would that be ?18:17
kristianpaulwell, there are two choices, re-use a sat or launch one18:19
wpwrakerr, in what context ?18:21
kristianpaulhave a satellite for own use?18:23
wpwrakah, i see. like some people have a cat. makes sense :)18:26
rejon_hahahah -> http://news.cnet.com/8301-17938_105-20006211-1.html?tag=mncol;txt19:55
rejon_from this -> http://news.cnet.com/8301-11386_3-20053249-76.html?fb_ref=fblike&fb_source=home_oneline19:56
wpwrakrejon_: i think we'll see it get a little fatter with time ;-)20:03
rejon_man, some group trying to get me to sign an NDA about mesh networking20:06
rejon_even though NDAs are meaningless20:06
rejon_wpwrak here's one for you: wow so cool http://online.wsj.com/article/SB10001424052748703841904576256512991215284.html20:07
rejon_<rejon_> "The Chinese company Huawei Technologies Ltd., one of the original contractors for Libyana's cellular network backbone, refused to sell equipment for the rebel project, causing Mr. Abushagur and his engineer buddies to scramble to find a hybrid technical solution to match other companies' hardware with the existing Libyan network. Huawei declined to comment on its customers or work in Libya. The Libyan expats in the project a20:07
rejon_sked that20:07
rejon_<rejon_>  their corporate affiliations be kept confidential so that their political activities don't interfere with their work responsibilities. "20:07
rjeffries_wpwrak have you looked at FunCubeDongle, softwrae defined radio? http://www.funcubedongle.com/20:14
Action: kristianpaul had one FunCubeDongle in his hands and pluged in his latop at labsurlab20:16
kristianpaulrjeffries_: its hardware schematics is under DNA, but work out of the box with free software ;)20:17
kristianpaulplus some atenas and RF stuff you can get excelent results, but i had heard it work fine just pluging the atena directly to it20:19
rjeffries_kristianpaul sure is a cool concept. wonder how well it works. it is not very expensive I think20:19
rjeffries_it==FunCubeDongle that is20:19
kristianpaul(ow well it works) take your time, but this is a good source http://www.oz9aec.net/index.php/funcube-dongle20:20
wpwrakrejon_: (libya) the devil's in the details ;-)20:45
rejon_the world's drug dealer20:46
wpwrakrjeffries: heard of it, yes. alas, not the most useful frequency range. also, very narrow-band. about 1000 times narrower than the usrp2. furthermore, rx-only.20:50
mthFYI: I added pokeparadox to the gmenu2x contributors23:42
mthso don't be alarmed if commits are coming in from a new name23:42
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