#qi-hardware IRC log for Friday, 2011-04-15

whitequarkwpwrak: here's the schematic http://rghost.net/5194403.view and board http://rghost.net/5194410.view00:00
wpwrakwhitequark: you measured that you don't have shorts ?00:01
whitequarktraces are 10mil. the soldering looks perfect: I may even place a light behind the board and see how traces and chip pads align to each other00:01
whitequarkchecked all the three identical boards a lot of times00:02
whitequarkfor shorts, openings, everything00:02
wpwrakwhitequark: those D+/D- traces don't look nice00:03
wpwrakwhitequark: you should keep them as short as humanly possible00:03
whitequarkwpwrak: then I won't be able to do it on one side, which equals to not being able to do it at all00:04
wpwrakwhitequark: also, are you sure the metal of your USB connector never touches the traces ?00:04
whitequarkI've checked00:04
whitequarkit has a bottom made of plastic00:04
wpwrakwhitequark: (one side) worst case, you would need a wire00:06
whitequarkI've leaved it plugged in for several minutes00:06
whitequarkit's hot00:06
wpwrakwhitequark: but you can probably do it as follows: rotate the chip so that D+/D- are very short. [...]00:06
whitequarkwell, the _working_ one I bought in store is exactly as hot as mine00:06
wpwrak(hot) that tells you something ;-)00:06
whitequarkI guess that's a feature somehow00:07
whitequarkall cp2102-s I've seen were hot as hell00:07
wpwrakwhitequark: (hot as hell) including boards made by others ?00:07
whitequarkwpwrak: yes, including perfectly working boards I bought00:08
whitequarkand on some Digilent board, too00:08
wpwraki can't remember the c8051f32x getting unduly hot, and the cp2xxx just seem to be variants of the same design00:08
wpwrakhmm. strange.00:08
whitequarkstill, it's hot.00:08
whitequarkand I agree that's very strange00:08
wpwrakwhitequark: anyway, back to D+/D-: rotate the chip. connect signal ground to shield ground. then you have ground on both sides, connected via the USB connector.00:09
wpwrakwhitequark: for extra paranoia points, connect the two ground sides also on the other end, under the header00:11
whitequarkI can't rotate the chip. the lines in cp2102 and the usb connector are reversed00:11
whitequarkthat wouldn't work in one layer00:11
whitequarkanyway, thanks for suggestion00:14
wpwrakah, right, they are. okay, option 1: use a reversed connector.00:15
wpwrakoption 2: use a 0603 0R resistor00:16
whitequarkhmm, the resistor00:16
whitequarkyes, it may be an option00:16
whitequarkI'll do the new pcb tomorrow I think00:17
wpwrakoption 3: use a full-sized USB plug (or make a PCB plug)00:17
kristianpaulwhitequark: hacking an atben? :)00:17
whitequarkwpwrak: through-hole mini-usb plug will work, too, as it'll go to other side of pcb00:18
wpwrakwhitequark: yes, if you can find one that actually does work ;-) have you used one of these yet ? how think are your PCBs ?00:18
whitequarkwpwrak: by PCB plug do you mean something like very cheap, small and crappy usb flash drives?00:18
whitequarkwpwrak: yes, I know where to buy some. my PCB is 1mm thick (0.8mm sheets often look bend in the shop, so I prefer to not buy them)00:19
whitequarkkristianpaul: no. just trying to do a cp2102 usb-uart for third, or maybe fifth, month00:19
whitequarkkristianpaul: that's going to become a project of my life00:20
wpwrakwhitequark: (pcb plug) yes, like this: http://downloads.qi-hardware.com/people/werner/tmp/usbpcbconn.jpg00:20
Action: wpwrak feels good. did idbg within something like one month, including writing the usb stack ;-) http://www.almesberger.net/misc/idbg/00:21
whitequarkwpwrak: (pcb plug) that'd help a bit some time ago when I was killing one usb connector after another with heat gun00:21
wpwrakwhitequark: (1 mm) okay, that should be thin enough00:22
kristianpaulwhitequark: oh, an fdti alternative, good :-)00:22
whitequarkwpwrak: (projects) I've actially did 3 or 4 projects in that timeline :) and sold two of them (other two were for me)00:22
whitequarkwpwrak: it's just the fucking cp2102.00:22
Action: kristianpaul never needed an idbg :p00:22
whitequarkkristianpaul: yeah. it looks good in the DS, it is cheap, it is installed on a lot of pre-manufactured boards00:23
whitequarkkristianpaul: but when you're trying to do one...00:23
wpwrakwhitequark: (heat gun) i see the words, yet i lack the comprehension00:23
whitequarkwpwrak: ahem. I think I've seen a phrase constructed like that somewhere00:24
whitequarkwpwrak: there is a tool for soldering smd components which generates hot air00:24
whitequarkwpwrak: I've just called it 'heat gun'00:24
wpwrakwhitequark: usb is very finicky. oh, and did you make sure all your fancy flux is washed off the board ? as in 3+ cleaning cycles with hot water and alcohol, using a brush ?00:25
whitequarkwpwrak: of course it wasn't. I may wash it 3 or 5 times, but if I heat it a bit... the flux instantly goes from all the hidden holes00:25
wpwrakwhitequark: (heat gun) okay, "hot air pen" or such then. "heat gun" is the construction-grade kind of device.00:26
whitequarkwpwrak: and how is it called correctly?00:26
whitequark(flux) I've heard of a chemical called FLUX-OFF from Cramolin. it's said to remove traces of flux easily and completely. maybe I'll buy one tomorrow00:28
wpwraki think it's just called "hot ait station". something like this, no ? http://www.howardelectronics.com/xytronic/852D.html00:29
wpwrakas opposed to this http://www.howardelectronics.com/navigate/hotairguns.html00:29
wpwrakor this http://www.howardelectronics.com/xytronic/hotairpencil.html00:30
whitequarkwpwrak: mine is the station one. particluarily, the big thing at the end of pipe is exactly the same00:31
wpwrakflux remover can help, yes. also picking a "friendly" flux should help. e.g., water-soluble. i wouldn't quite trust "no-clean". sometimes it does need cleaning anyway, and then it's harder to get rid of than water-soluble00:31
whitequarkwpwrak: hmm, I do have water-soluble. it's called TAGS, and it is based on glycerine00:32
wpwrakokay. good station. yet unnecessary for such a simple circuit. just a temperature-controlled soldering iron would do nicely ;-)00:32
whitequarkwpwrak: the station is different, through. mine has an temp-controlled iron too :)00:33
wpwrak(flux) as long as it's for electronics ... (no idea what they put inside)00:33
wpwraklike this ? http://www.howardelectronics.com/xytronic/Images/988DLWFume.jpg00:33
wpwrak(that's the one i have)00:33
whitequarkwpwrak: (flux) wouldn't traces of water stay all under the smd components and interfere with its operation?00:34
whitequarkwpwrak: (station) mine is: http://www.china-zhongdi.com/zd-912.htm00:34
wpwrakthat's why you clean with alcohol afterwards. plus, water eventually evaporates. what's more of a problem are salts. they're okay while dry but when the circuit gets moist for some reason (e.g., condensation), they'll start conducting.00:35
wpwrak(station) looks nice00:35
whitequarkwpwrak: (flux) well, everything other I've tried works with Pb/Sn+RMA perfectly00:36
whitequarkmostly atmel controllers with a few peripherals, but there were various circuits00:36
wpwrakRMA is a bit hard to remove. but yes, it has good wetting properties. better than water-soluble or no-clean00:37
wpwrakwere the atmels qfn, too ?00:37
whitequarkwpwrak: no, only tqfps. I didn't have a reason to pick qfn atmels00:37
wpwrakaha ! qfn is trickier :)00:38
wpwrakdid you try to solder the center pad ?00:38
whitequarksure, it should be soldered per DS00:38
wpwrakwell, if that chip gets so hot, you may actually need it ...00:39
whitequarkthey require a ground connection there00:39
wpwrakthe center pad is tricky. trying to solder it can easily make things worse.00:39
wpwrak(ground connection) that's what they all say ;-)00:39
whitequarkwpwrak: so, everybody lies?00:40
wpwrak(trying) the emphasis is on "trying". can cause shorts with adjacent pads, and you can get solder paste residues there as well.00:41
wpwrakoh, i'm sure the chips work better if you solder the central pad and do it properly ... ;-)00:41
whitequarkwpwrak: I have a bright LED lamp, and the pcb is thin enough00:42
whitequarkwpwrak: I can either look through it or look at reflected light00:42
whitequarkin both cases I can see the soldered and unsoldered bounds of the central pad (the pcb polygon is a bit narrower than the pad itself)00:42
whitequarkthere's no shorts00:43
wpwrakdunno such things are easy to spot00:43
wpwrakanyway, here's how i do qfns: set the soldering iron to a temperature where the solder liquifies conveniently. this is usually relatively hot. but better to go in hot and out again quickly than having to roast the contacts for a long time00:45
whitequarkwpwrak: that's 300 for me00:45
wpwraknext, pre-tin all the pads. (apply flux everywhere, deposit a droplet of solder, then sweep with the soldering iron over the board)00:46
wpwrakthen, wash off all the mess. (water+alcohol+brush)00:47
wpwraknext, flux the qfn's pads, place the chip, hold it down with tweezers, and apply solder all around. chances are that only a few pins will be soldered and there may be many solder bridges. that's okay. in the first round, the objective is to just make enough connections to keep the chip in place.00:48
wpwrakthen, add flux again and add solder where needed and/or redistribute the solder. it's also good to do one side at a time, i.e., apply solder, do one pass, apply solder the next side, do that side, etc.00:49
wpwrakmay need 2-3 passes until everything looks right. remove excess solder with a braid.00:49
whitequarkhmm, I'll try this00:50
whitequarkwhat flux do you recommend?00:50
wpwrakby then, all the "good" contacts should be detectable by visual inspection. particularly if using leaded solder and not having big ground planes.00:50
wpwrakthen you can go around and look for shorts. it also helps to have "needle" type probes.00:51
wpwrak(flux) i use water-soluble most of the time. i find it a good compromise between resin (RA/RMA) and no-clean.00:52
whitequarkwpwrak: what one? I may even order it from [name of the place you live in]00:52
whitequarkjust because I'll then get A Flux That Definitely Works00:53
rohmeh. moving is tireing00:55
wpwrak("needle" probes) like these: http://www.fluke.com/Fluke/usen/Accessories/Test-Leads-Probes-and-Clips/TL910.htm?PID=5676100:56
whitequarkwpwrak: ah yes, I have something like that. they're a bit thicker when it's far from tip, but still work00:57
wpwrakwhitequark: i mail-order from the us ;-) (digi-key) my flux is the kester 2331-ZX00:58
whitequarkwpwrak: looks you now have... a LOT of that flux01:00
wpwrakah cool, digi-key don't have that flux anymore.01:00
wpwrak(a LOT) why ? bought just two pens. and the first one is still half-full ;-)01:00
whitequarkwpwrak: the link I've found: http://www.kester.com/SideMenu/Products/WaveSolderingMaterials/Fluxes/tabid/250/Default.aspx01:01
whitequarkah yes, that's not an order number, but a product number01:01
wpwrakthose fluke probes are spring-loaded. and they come with a set of tips: needle and "crown" (three tips). the latter is good to grab the edges of 0402 components and such. these probes are really great.01:02
whitequarkwpwrak: 0402 is still too hard for me. I don't even know where I can buy 10's of those01:02
wpwrakah, i use flux pens, not bottles ;-)01:03
whitequarkhmm, flux pens... any ideas where can I order a pair of these?01:04
wpwrakdigi-key ?01:04
whitequarkin russia?01:04
whitequarkhm, they actually have a working site digikey.ru01:05
whitequarkmay be an option01:05
wpwrakhttp://www.digikey.ru ;-)01:05
wpwrakyeah. i think that's just a front-end, though. they still ship form the US.01:05
whitequarkso, The Russian Postal Service strikes again01:06
whitequarkah well, I've probably found an error in my design.01:06
whitequarkI've connected an NC pin to ground... that may have been worked, but it was marked in a footnote as "not connect or connect to Vdd"01:07
wpwrakhere's the pen: http://www.kester.com/SideMenu/Products/HandSolderingMaterials/FluxPens/tabid/263/Default.aspx01:07
whitequarklooks like that _is_ a short which would go unnoticed through all the checks01:08
wpwrakhmm, digi-key don't seem to have any flux pens with water-soluble flux anymore. pity. maybe the no-clean ones got better.01:09
wpwrakNC to GND could be bad news, yes01:10
wpwrakwhich pin was it ?01:10
wpwrak18 is P2.1 ... that one should be high-Z (unless they did something weird)01:11
wpwrak(i think the c2102 is a c8051f327 on the inside)01:12
whitequarkoh, it's 5am again01:12
whitequarkI'll go sleep now :/01:12
wpwraknow *this* is what i call a lab ;-)) http://www.heise.de/tp/bild/34/34544/34544_1.html04:10
rejonBen WPAN06:02
rejonshould be called SLoPAN06:03
rejonor rather SLoPan06:03
rejonlike that06:07
rejonthat is some good shit06:07
rejon6LoWPAN already looks cool06:07
rejonbut ppl will never pronounce that right06:08
kyakrejon: do you want to make it sound "slow" intentionally? :)06:59
viricInstead of thinking about a wireless nanonote....07:49
viricHow far can a wired nanonote be from a internet-connected computer? :)07:50
kyaki guess there are 10 m USB extenstion cables07:53
kyakthe question is if they would work07:53
viricAh I meant *working*, yes. :)08:39
wpwrakrejon: i actually wonder where "Slowpan" comes from and if 6LoWPAN could maybe come from "Slowpan".10:04
zedstarslowpan...cool...although it does sound a bit like a grill that george foreman might market10:43
wpwrakzedstar: ;-))11:36
mat619hey there. i need some help with a HP nc6120 notebook. it doesn't power on anymore at all, regardless of AC power, battery in or not and being docked or not. any ideas where to start looking for errors?13:01
mat619hey there. i need some help with a HP nc6120 notebook. it doesn't power on anymore at all, regardless of AC power, battery in or not and being docked or not. any ideas where to start looking for errors?14:15
kristianpaulwrong channel, this is copylyeft hardware, try on #hardware please14:16
mat619ooops. okay! sorry and have a nice day!14:28
rjeffrieswpwrak looking ahead, what will need to change to acieve greater range with ATBen and ATUsb?15:49
rjeffriesin a future iteration, would allowing an external antenna allow it to work at greater distances?15:50
rjeffrieswpwrak in NO WAY am I complaining your work is Most Excellent!15:50
rejongetting better! http://en.qi-hardware.com/wiki/Ben_WPAN16:09
rejonwho has ops in here?16:20
wpwrakrjeffries: a better antenna could help, yes. although i didn't see much of a difference between the pcb antenna and the usual ~10 cm wifi antennas16:27
wpwrakrjeffries: (an external antenna also needs a connector and probably a cable, so you have a bit of losses there as well.)16:27
wpwrakrjeffries: the chip has more features, though: 1) it supports antenna diversity: two antennas and it picks the one that has the best reception. 2) it can drive an external amplifier. each such improvement needs one extra chip and some other RF components.16:29
wpwrakrejon: whee, nice ! maybe also mention that the first goal is just plain internet connectivity ?16:31
wpwrakrejon: UBB is more a byproduct. ancestry goes a bit like this: first were the odd ones on the top of http://downloads.qi-hardware.com/people/werner/wpan/tmp/boards-so-far.jpg16:41
wpwrakrejon: the idea was to have a single design, with one side doing USB-to-SPI while the other did RF. then, one could either use it with USB, or cut it in the middle, and implant the RF-only part in a ben.16:43
rejonthat is great16:44
rejonthis is so cool16:44
rejonthe sensor approach is great16:44
wpwrakrejon: then Ornotermes had the idea to use the 8:10 card slot for I/O (unrelated to wpan). I then made the blinkenlights board and UBB is an offspring of that16:44
wpwrakrejon: (sensor) which sensor ?16:44
rejoni mean, that is what i'm most interested in16:45
rejondata gathering16:45
wpwrakrejon: (cont'ed) another offspring of blinkenlights is the design change on wpan: instead of one unified design, make two: one for USB, the other for the Ben.16:45
wpwrakrejon: one of the first ben-only designs were the one labeled "A" and "B" (100903). note that they didn't have a crystal. back then, i thought i could just let the ben provide the clock for the RF subsystem.16:47
wpwrakrejon: the other fork of wpan was the atusb board, first with an USB-capable MCU from SiLabs. labeled "2", "3" (20101229)16:48
wpwrakrejon: each of the designs had one major design change: i had to add a crystal to atben, because the ben's own clock was too noisy. you can see a first try in the middle of the image, labeled "20110115"16:49
wpwrakrejon: i did a few more design variations of atben, mainly to make it smaller: http://downloads.qi-hardware.com/people/werner/wpan/tmp/atben-110219-compare.jpg16:51
wpwrakrejon: the one in the middle was a slightly reduced version of 20110115. the one in the lower right corner is the final result (or very close to it)16:52
wpwrakrejon: on the atusb side, i replaced the silabs mcu with one from atmel: http://downloads.qi-hardware.com/people/werner/wpan/tmp/atusb-20110131.jpg16:52
wpwrakrejon: (because atmels are more popular in the DIY scene and also because there's better compiler support - nice gcc instead of buggy sdcc)16:53
wpwrakrejon: so that's the story of the wpan and the blinkenlights/ubb families :)16:54
kristianpaulhe, one year later http://www.sigmaelectronica.net/mrf24j40mair-p-1498.html16:54
rejonwpwrak can you drop some knowledge on that wiki page?16:56
rejoni like calling this SLoWPAN16:56
rejonthat is a good to market16:56
rejonjust like Slowfi16:56
rejonbut slowfi is more about culture16:56
rejonterm i came up with some time ago16:56
rejonwe have all the domains on it16:57
wpwrak(slowfi) oh, indeed :-)16:57
rjeffrieswpwrak what have we heard form Tuxbrain about the process of manufacturing initial run of AT-Ben and AT-Usb?17:00
rjeffriesthe suggested qty 1 prices of thes etwo wpan boards (Ben and US) add up to more than a Ben if my math is correct17:02
wpwrakrjeffries: not unless the ben has gotten a lot cheaper recently ;-) but i don't know his final prices. not sure if he does ;-)17:09
wpwrakrjeffries: (manufacturing) the pcb fab has sent back the panelized gerbers a few days ago. we sent them back some comments. not sure what has happened since.17:10
rejonwpwrak http://en.qi-hardware.com/wiki/Ben_WPAN updated18:03
rejonif you can put some latest outcomes, pictures and more and we can get rjeffries to add some thoughts, great!18:03
rejoni tried to make simple18:03
rejonwould love to add more innovation pages like this18:04
wpwrakpheew ... "a next generation wireless personal area network" seems a bit bold ;-)18:13
wpwrakrejon: it's more like "poor man's wifi for now, then see what else it's good for" :)18:14
rjeffrieswpwrak assume all the atBen and atUsb units you shipped have arribed at their destinations?18:14
rjeffrieswpwrak who besides wpwrak has been able to make a wireless connection using your devices?18:15
wpwrakrejon: "patent-free playground" may also be overstated. there are almost certainly a lot of patents around, too. it's just that the basic technology (chips, etc.) is more accessible than, say, with wifi. in the sense that you can easily buy chips, there are public data sheets, etc.18:16
wpwrakrjeffries: not sure if richard or tuxbrain tried. afaik, roh doesn't have a usable ben.18:17
rjeffrieswpwrak 6LoWpan protocol is (I think) completley free and open, correct?18:17
Action: kristianpaul smile for a wpan-sdr ;-)18:17
rejonwpwrak rjeffries please directly edit the page! :)18:18
wpwrakrjeffries: to the extent that anything recent can be completely free and open, given the current patent system18:18
rjeffrieswpwrak did you send a set of atben atUSB to xiangfu (sp??)18:19
kristianpaulrejon: i dont bet werner will touch wikis ;-)18:19
wpwrakrjeffries: nope, only to adam (forwarded to tuxbrain), roh, and richard18:21
wpwrakkristianpaul: only occasionally and reluctantly :)18:22
rjeffriesoh ok. Adam is looking at manufacturing aspects I assume?18:22
wpwrakrjeffries: that was the original idea. but now it's tuxbrain who will do the manufacturing.18:22
kristianpaulrejon: no, he is busy with mm1 RC3 i think18:22
rjeffrieswpwrak I talked with an engineer friend yesterday and he's interetsed in seeing the atUSB and related docs, thinks he might repeat might have an application18:23
rjeffrieswre there a few good links? I would then attempt to add themin Wiki to the stuff rejon recently crafted\18:24
rejonyeah, cool18:24
wpwrakrjeffries: maybe start with the schematics ? http://projects.qi-hardware.com/schhist/atben/ and http://projects.qi-hardware.com/schhist/atusb/18:24
rjeffriesbut maybe Adam will give advice to tuxbarin, who knows18:24
rjeffriesthanks wpwral18:25
wpwrakrjeffries: then the fab files (gerbers) are here: http://downloads.qi-hardware.com/people/werner/wpan/fab/18:25
wpwrakrjeffries: overview images of the layout: http://downloads.qi-hardware.com/people/werner/wpan/tmp/atben-110324-overview.png http://downloads.qi-hardware.com/people/werner/wpan/tmp/atusb-110330-overview.png18:26
wpwrakrjeffries: last but not least, all the design files, firmware, tools, etc.: http://projects.qi-hardware.com/index.php/p/ben-wpan/source/tree/master/18:27
wpwrakrjeffries: (advice) yes, adam is making suggestions18:27
rjeffriesoh welll my OpenID credentials are not working for the wiki18:28
rjeffrieswpwrak I CCd you on my email to John Baggs. he is one of the small group of gifted engineers typified by wpwrak.;)18:42
wpwrakrjeffries: thanks !18:58
wpwrakwikinnoyance: URLs that end in .ogv but are HTML ...19:23
whitequarkwpwrak: hi again20:13
whitequarkI have a weird question for you as electronics/wireless professional ;)20:13
whitequarkI have a bluetooth headset, and sometimes I have a weird feeling that the samplerate for the sound is off for maybe 100Hz, e.g. it plays at 44000 instead of 4410020:14
whitequarksomehow this only appears after it is interrupted by activity of other devices on the same bluetooth adapter, i.e. a mouse20:15
whitequarkif that's true, how that can ever be (I assume that the sound samplerate is derived from the main crystal inside), and if it isn't, why it constantly appears and only with this particular headset?20:15
wpwrakwhitequark: does the sample rate seem to stay off after the interruption ? or does it only briefly seem to change ?21:20
whitequarkwpwrak: before the interruption it is OK21:26
whitequarkand after it it stays for at least a minute21:27
whitequarkand, given the fact there is no noticeable change, it either slowly returns to original value, or that's just I'm getting used to it21:27
whitequarkthe effect is absolutely reproducible, at least on one song I can interrupt it in a certain place and instantly hear the weirdness21:29
whitequarkwell, that still may be the human acoustic tract characteristics21:29
wpwrakwhitequark: hmm, could be some error correction and/or buffering bug.probably not much you can do about it.22:03
whitequarkwpwrak: there is around a second of buffer in this device. ECC... hm, how that can affect it this way?22:05
whitequarkthe interruption is as follows: first, it plays for ~second, then it interrupts for 0.8 sec, then it plays again for 0.3 sec maybe, and then it is silent again22:06
wpwraki don't know the error correction BT uses, but it could be just some badly implemented interpolation22:06
whitequarkthe problem is that I'm not sure what does happen there exactly, and I'm curious about it22:07
wpwrakoh, the audio stream gets fully interrupted ? that's bad22:07
whitequarkwpwrak: bluetooth audio is fully digital, and ECC is done on lower layers. also it uses some compression for audio22:07
whitequarkI don't believe it can just be interpolated22:07
wpwrakwell, some form of interpolation. not necessarily a straight line ;-) but you have all sorts of layered codings and such, where (small) data loss means loss of quality, not all-or-nothing operation22:09
wpwrakbut if you really want to know where they screwed up, you'd have to find out what protocols and codings exactly are used there.22:10
whitequarkI know that it uses A2DP22:14
whitequarkhmm, as the first step I'll try to play sine, then record it and analyze22:14
whitequark*sine wave22:14
wpwrakyup, that's a very good idea. get the human factor out of the system ;-)22:15
qi-bot[commit] Cristian Paul PeƱaranda Rojas: Fake file for testing purposes http://qi-hw.com/p/ben-gps-sdr/df9f53922:37
qi-bot[commit] Cristian Paul PeƱaranda Rojas: some ugly fixes http://qi-hw.com/p/ben-gps-sdr/f35f4fc22:37
--- Sat Apr 16 201100:00

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