#qi-hardware IRC log for Tuesday, 2013-12-24

nickoewpwrak_: though the generated footprint seems a bit odd in the kicad format00:16
nickoewpwrak_: there is no bottom pad00:17
wpwrak_for experimenting with it, you could try to run the kicad module editor and change the holes to through-hole pads00:33
wpwrak_that may solve this sort of issues00:34
wpwrak_if the result is good, i can later make fped make such adjustments00:34
whitequarkrelevant to our recent discussion:http://www.jakoblell.com/blog/2013/12/22/practical-malleability-attack-against-cbc-encrypted-luks-partitions/00:54
whitequark... wait, LUKS doesn't use authenticated encryption? O_O00:54
whitequarkah, it does by default, but only since recently.00:58
wpwrak_hehe. too bad the bird didn't take off. it's fun to watch them fly after a good drink :)02:07
whitequarkwpwrak_: how would you know?02:19
wpwrak_once upon a time, when i was still a student, when a party came to an end at sunrise, we went to sit outside. one guy had a bottle of whisky. someone had some bread. the two were quickly combined and offered to the birds who showed considerable interest. afterwards, their flight pattern was a bit "wavy".02:28
wpwrak_i thnk it was mainly sparrows, so a few pieces of alcohol-soaked bread already have an effect02:29
wpwrak_anyway, time to begin preparing my den for tomorrow's party02:30
whitequark"wavy", heh02:40
kyakstudents that 1) drink whisky 2) share whisky with birds. What were you, millionaires? :)05:46
nicksydneywpwrak_: the new copper board + the blue paper pays off completely !07:09
nicksydneyhere is the result07:09
nicksydneyok time to get out of the house and enjoy day before christmas with the family....07:15
nicksydneywpwrak_: looks like will need to buy few stuff for etching :)..will chat with you later about that ;)07:15
DocScrutinizer05wpwrak_: there are a few variants of LED formfactor: http://www.digikey.com/product-detail/en/HSMW-CL25/516-2278-6-ND/242817708:29
DocScrutinizer05or how about the smallest RGB LED? http://rohmfs.rohm.com/en/products/databook/datasheet/opto/led/chip_multi/smlp36.pdf09:25
DocScrutinizer05ok, a shocking EUR1.2009:27
DocScrutinizer05though seems 1.0*1.0*0.25mm is 'smaller'  http://media.digikey.com/pdf/Data Sheets/Lumex PDFs/SML-LX0404SIUPGUSB.pdf09:29
wpwrak_nicksydney: whoo ! santa claus brought you a nice board !10:42
wpwrak_DocScrutinizer05: (form factor) sure. but also keep in mind sourcing. e.g., the one you showed is "Quantity Available: 0". especially if you need a every specific form factor, things get hairy very quickly10:47
wpwrak_DocScrutinizer05: but yes, if you can find something more convenient and with a few sources that exist in real life, why not10:47
DocScrutinizer05anyway, there's really awesome stuff, check out THIS! :-O   http://www.digikey.com/product-detail/en/OVSRWAC2R6/365-1550-1-ND/220354910:48
wpwrak_btw, about LEDs: one little detail is that some have just two pads while others have one pad extend a bit into the middle. so if you try to run a trace across the LED, you may find some surprises10:48
DocScrutinizer050.08mm .oO(?!!?#@@#*§$@)10:49
wpwrak_the technical term for this is "typo" :)10:50
DocScrutinizer05nah, check it!10:50
wpwrak_digi-key has lot of little errors. and others do, too. e.g., farnell thinks they have PCBs with a thickness of something like 30 um ;-)10:50
DocScrutinizer05is Cd teh brightness when you look at the bright spot, or the photon flux?10:51
whitequarkthey put those blue LEDs in appliances which light up your room rather bright at night10:51
DocScrutinizer05for the former the 0.08mm easily make for en intense but tiny bright spot at the source10:51
whitequarkso I won't be surprised10:51
whitequarkalso whoever came up with that brilliant idea should have his eyelids cut and superbright blue LEDs glued directly to corneas10:51
wpwrak_mcd goes up as the angle goes down. so you always need to check the two10:52
DocScrutinizer05the Cd values are consistent in datasheet min max avrg and digikey10:52
wpwrak_but you realize that it's not 0.08 mm ?10:52
DocScrutinizer05it isn't?10:52
wpwrak_of course not. 0.8 mm. see the data sheet.10:52
wpwrak_and also no stock, "call for price", and so on. this is just trouble.10:53
DocScrutinizer05yes, seen the (CALL)10:54
DocScrutinizer05not considering to get it10:54
wpwrak_nicksydney: the large surfaces are amazing. very neat. you have a few broken traces, though. that may be uneven ironing. so maybe you can improve that. these' get a very fine permanent marker and draw the missing bits. the permanent marker will act as a (weak) etch resist, too10:55
wpwrak_nicksydney: you also have some blurring in the lower right quadrant. that's caused by too much ironing. but it's not too bad. you can just scrape off the toner between traces with a sharp knife10:57
wpwrak_also, if you overlook such small problems, you can fix them later by cutting through copper, by bridging small cracks with solder, and by adding wires to bridge larger gaps10:58
wpwrak_but the further you get in the process, the harder it is to fix things10:58
whitequarkwpwrak_: I'd wait for it to etch... seen etchant eating/seeping through toner much more than once11:18
wpwrak_ah, russian toner ;-)11:19
whitequarkhttp://quinndunki.com/blondihacks/?p=1486 mentions she uses two layers of toner for that11:19
whitequarkwhich I guess makes sense, but even more hassle11:19
wpwrak_or is it the radioactive acid ? :)11:19
whitequarknot just russian... see above11:19
wpwrak_naw, that's over-engineering11:19
whitequarkI'd say the process has far too many variables to be reliably reproduced :p11:20
whitequarkbtw I bought that press-n-peel stuff, but it'll take a while for it to arrive here11:21
whitequarkholidays and stuff11:21
wpwrak_yeah. just make sure your basic process is reasonable. fix the glitches. i don't usually get 100% perfect boards but it's generally not a big deal to fix the few small issues (mainly fissures in the toner that lead to broken traces)11:22
wpwrak_what's important is to check the traces before soldering component. nothing like having some bit chip or connectors sitting on a broken trace ...11:23
wpwrak_or, better, a shorted trace11:23
wpwrak_and for etching, one important part is to get an acid that actually works. something that takes an hour before it even notices the copper is almost guaranteed to creep into the weirdest places11:25
wpwrak_of course don't use 30% HCl + 30% H2O2 either :) (super-fast. etches a board clean in something like ten or twenty seconds. the acid starts to boil in the process. has a certain tendency of overlooking toner. so you get something that still resembles the original layout but won't be of any use.)11:30
whitequarkmy FeCl3 solutions took about 20-30 minutes, my (NH4)2S2O8 solutions took about 10 minutes to etch11:32
whitequarkstill creeps around toner11:33
whitequarkto significantly varying extent11:33
wpwrak_FeCl3 is just dirty11:34
wpwrak_dunno the other11:34
wpwrak_do you need to heat the ammonium ?11:35
whitequarknaw, it's supposed to work well at room t°11:35
wpwrak_good. that's another nasty bit of FeCl311:35
whitequarkoh right, I didn't heat it, since I didn't really have appropriate equipment for it11:36
whitequarkthat explains why ammonium results were better and why FeCl3 results were bad...11:36
wpwrak_i wonder what kind of pervert ever thought of using FeCl3 in the first place. it basically has all the characteristics that may it as painful as possible to use.11:36
whitequarkwell, it's the most well-known and used etchant in russia11:37
wpwrak_yes, but why ? it just sucks11:37
whitequarkmaybe that's the reason :]11:37
whitequarkyou should feel the most pain possible no matter what you do11:37
wpwrak_doesn't work at room temperature, it stains, it barely transparent when new and fills up with black sludge in use, making it opaque, it's slow, disposal is a mess, and so on11:38
whitequarkdisposal? just pour it down the toilet11:38
wpwrak_yeah :) if you didn't have to suffer it doesn't count :)11:38
wpwrak_ok, russia ;-)11:39
whitequarkoh, would it dissolve your pipes?11:39
wpwrak_depends on whether it can get trapped somewhere. but i was more thinking of toxidity.11:40
wpwrak_and of course, since it stains everything, your toilet may get a little harder to clean if you do tht regularly11:40
whitequark(toxicity & co) I don't think whatever amount of hobbyists purging their FeCl3 down the drain are going to produce any observable effects11:42
whitequarkexcept maybe very locally, if they have that kind of sewage disposal11:42
whitequarkFe cations aren't exactly rare in nature either way, there's whole rivers full of that11:43
wpwrak_yeah, chances are it pales in comparison to whatever the factories in your area pump out11:43
whitequarkthat too11:43
whitequarkI could understand if it was Cd or Hg or something worse, though I doubt that would be really that bad either11:44
whitequarkFe? *shrug*11:44
wpwrak_fish really seem to hate it11:45
whitequarkmhm, yes. but the amounts are still tiny. it's visible when done on scale11:46
whitequarkI find it rather ironic that Chromebooks from the oh-so-evil Google in near future will probably be one of the safest and most open pieces of hardware12:40
whitequark> http://www.phoronix.com/scan.php?page=news_item&px=MTU1MTk12:40
whitequarkI don't think there is any other relatively modern (5yrs) Intel platform with coreboot support other than chromebooks12:42
DocScrutinizer05the issue with at least ammonia persulfate: it's rated. Possible to dual-use it ;-) Too much oxygen in there13:38
whitequarkDocScrutinizer05: not here13:39
DocScrutinizer05I can't seem to buy it anywhere around here, without showing my ID card and a commercial Addr13:39
whitequarkI just went to a market (not like a flea market. it's an organized, licensed group of small shops) and bought a small can13:39
DocScrutinizer05whitequark: in Russia you got easy access to way better explosives ;-P13:40
DocScrutinizer05so why rate/restrict ammonia persulfate13:40
whitequarkwell, as discussed earlier, you can't really buy HCl or KMnO4 (at all!) or other seemingly innocious substances13:40
DocScrutinizer05no kalium permanganate? why that?13:41
whitequarkoxidizer, and in this case I think it can be used for making drugs13:41
DocScrutinizer05it's not like you need KMnO4 for explosives. You can substitute by Kalium Chlorate for example?13:41
whitequarkit used to be a really popular disinfectant, now it's prohibited *completely*13:41
DocScrutinizer05OOOH drugs13:42
DocScrutinizer05may be13:42
whitequarkwell, "can't really buy" apparently means "go 15km behind city border to the factory with a bottle of vodka"13:42
whitequarkyou need a bit of inside knowledge though but it's not exactly hard13:42
whitequarkas an additional perk, you probably couldn't buy *less* than several kg of that stuff13:43
DocScrutinizer05It's no 4 weeks ago I read a mentioning how to synthesize KMnO413:43
DocScrutinizer05possibly even by using Ammonia persulfate13:43
Action: DocScrutinizer05 idly wonders how to synthesize H2O213:44
whitequarkwhat for?13:45
whitequarkalso, wikipedia lists no less than four pathways13:46
whitequarkand I bet you could find a shitload of paper with incredibly detailed descriptions13:46
DocScrutinizer05just curious13:47
DocScrutinizer05it seems it's not THAT simple to get high percentage H2O213:47
whitequarkthat would really depend on quantities and costs you need13:49
DocScrutinizer05this must be nasty stuff13:52
whitequarkoh, neat, never heard about this before13:53
DocScrutinizer05well, instable like quarks13:54
DocScrutinizer05in water it breaks up in milliseconds13:54
whitequarkDocScrutinizer05: I highly recommend this: http://pipeline.corante.com/archives/2010/02/23/things_i_wont_work_with_dioxygen_difluoride.php13:54
whitequark"And he's just getting warmed up, if that's the right phrase to use for something that detonates things at -180C (that's -300 Fahrenheit, if you only have a kitchen thermometer). The great majority of Streng's reactions have surely never been run again. The paper goes on to react FOOF with everything else you wouldn't react it with: ammonia ("vigorous", this at 100K), water ice (explosion, natch), chlorine ("violent explosion", so he added i14:01
whitequarkt more slowly the second time), red  phosphorus (not good), bromine fluoride, chlorine trifluoride (say what?), perchloryl fluoride (!), tetrafluorohydrazine  (how on Earth. . .), and on, and on. If the paper weren't laid out in complete grammatical sentences and published in JACS,  you'd swear it was the work of a violent lunatic."14:02
wpwrak_the most remarkable thing is that he lived to write about his experiments14:03
DocScrutinizer05gives me a laugh :-D14:03
DocScrutinizer05wpwrak_: indeed14:04
DocScrutinizer05tetrafluorohydrazine WTF?!14:04
whitequarkchlorine trifluoride: "It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively."14:04
whitequarkand he mixed it with FOOF.14:05
DocScrutinizer05>>Tetrafluorohydrazine is used as a high-energy liquid oxidizer in some never flown rocket fuel formulas.<<14:06
wpwrak_never flown ... not even as shrapnel ?14:07
Action: whitequark is reading MSDS for ClF314:07
whitequark"However, the dry ice bath embrittled the steel container wall, which split while it was being maneuvered onto a dolly, instantaneously releasing 907 kg (2,000 lb) of cold ClF3 liquid onto the building floor.14:07
DocScrutinizer05this guy should stop injecting this mix of testosterone and angel dust and speed14:08
whitequarkthat must have been fun14:08
DocScrutinizer05wow, the criticality events of chemical labs14:09
whitequark"One eyewitness described the incident by stating, The concrete was on fire!14:10
DocScrutinizer05reading such story I'm ahppy about our container station moved away from vicinity of my house14:10
wpwrak_if already find it sufficiently encouraging if something explosively reacts with water ice.14:11
DocScrutinizer05nice even14:11
wpwrak_i mean the fire police already has a hard enough time with metal fires, and there's it's merey the heat splitting the water (causing hydrogen explosions)14:11
whitequarkwpwrak_: talking about metal fires, there's this further thing about ClF314:12
DocScrutinizer05they should check if it could get used for laser just like H2+F214:12
whitequarknormally it passivates a metal, but if you scratch it... yeah, the layer doesn't form quickly enough14:12
whitequarkso you have to deal with a metal fire in addition to whatever else is it burning through14:12
whitequarkbasically, everything will be on fire14:13
DocScrutinizer05real fun14:13
whitequarkLC50:  299 ppm for 1 hour rat (death due to respiratory14:13
wpwrak_DocScrutinizer05: this is a fun read: http://www.lfks-th.de/de/lfks/ice/offen/BuK%20Eisenbahntunnel/pdf/brand_ice.pdf14:14
whitequarkwpwrak_: that's in german and uncopyable. a summary?14:15
wpwrak_DocScrutinizer05: note especially: 1) the first call to the firefighters. 2) how the amount of equipment deployed upon that call corresponds to what was reported. 3) how all that relates to the what they had there in the end.14:15
wpwrak_whitequark: an ICE (german high-speed train) locomotive started to smoke. so they called the fire police to inspect it. they said it's just smoke, no fire.14:16
wpwrak_whitequark: fire police dispatched some five cars and 14 men. they found there was a little fire. so they tried to extinguish it ...14:17
wpwrak_whitequark: some five hours later, and with pretty much every firefighter of the wider area at the scene (including specialized industrial units, i think), they finally had the fire under control. it still flared up for two hours or so.14:19
wpwrak_basically anything they threw at it just dissolved, had no effect, or even fueled the fire14:19
whitequarkwhat exactly was on fire there?14:20
wpwrak_ah yes, in the end a total of 55 men were deployed. don't know how many more cars. at least one special unit.14:21
wpwrak_it was a short-circuit that started it. not sure what burnt first. there must be some things that don't take much. then there are large transformers with oil. and then the metals.14:22
wpwrak_e.g., aluminium will burn if the fire is just hot enough14:23
nicksydneymerry christmas to all14:30
nicksydneywell it's christmas morning here by the way .. 1.30am :)14:30
nicksydneywpwrak_: last time you were telling me about etching using acid and something can't remember what it was14:30
nicksydneywpwrak_: can you refresh my memory14:31
nicksydneywpwrak_: oh by the way before i start etching will buy some sharpies...but seems like i will need a thin sharpie for the broken traces14:31
wpwrak_nicksydney: merry x-mess ! ;-)14:36
wpwrak_nicksydney: muriatic acid and peroxide. cheap, easy to obtain (except when you're in russia), nice to handle (just make sure you have good ventilation, window or work outside. the chloride gas, while not harmful in that concentration can still do damage to metals if you give it enough time)14:38
wpwrak_(sharpies) yup. get the finest you can find. you can draw lines thinner than the tip width by not fully touching the board but it's a bit difficult. so a fine tip helps.14:40
nicksydneylet me google muriatic and peroxide14:41
nicksydneythis .. http://www.bunnings.com.au/-bondall-500ml-hydrochloric-acid-_p0960231 ?14:42
wpwrak_also, if you "fatten" a trace and you made it too fat, you can let the ink dry and then scrape some off with a knife.14:42
wpwrak_nicksydney: we had a loooooong discussion of the etching process. it starts here: http://irclog.whitequark.org/qi-hardware/2013-12-04#576170014:43
nicksydneylet me search in the irc log14:44
wpwrak_that 500 ml bottle looks good. 26-30%, that's a reasonable concentration14:45
nicksydneyyes...here was the discussion http://irclog.whitequark.org/qi-hardware/2013-12-07 :)14:46
wpwrak_not sure what the titanium dioxide the mixed in does. 14:46
nicksydneyok for the peroxide last time i showed you this  http://www.chemistwarehouse.com.au/product.asp?id=5439  :)14:46
nicksydneyanother $10 need to be spent tomorrow :)14:47
wpwrak_3%  .. yeah, that'll do. if you can get something a little stronger, even better14:47
nicksydneyok last in our discussion i was still not sure about "mixing is about two parts 3-5% peroxide and one part HCl"14:48
wpwrak_a mix with 3% peroxide is relatively slow and can't be reused much14:48
wpwrak_that's the mix you use to begin. afterwards, you can reuse the acid for a very very long time (months if not years)14:49
nicksydneyso say for example i use the measurement using the lid of this bottle http://www.chemistwarehouse.com.au/product.asp?id=5439 .. so if i want to measure that way and if i use 2 lid measurement of peroxide..how many lid measurement of the acid i must mix in ?14:50
wpwrak_the chemistry changes and you get a cupric acid. you need to "boost" that acid with oxygen (peroxide) and chloride (muriatic acid). so when the acid gets weak, you add some of these and it'll be strong again.14:50
wpwrak_not, the issue is that, the more you add, the more water gets into the mix. at some point the water will dilute things just too much. with higher concentration peroxide you add less water and thus don't dilute it so quickly.14:51
wpwrak_one HCl14:51
wpwrak_but you don't have to be super precise. just make rough guesses. when you top off the acid later on it's all guesswork anyway. it works over a wide range of mixes so unless you're walter white, just accept that things aren;t always perfect :)14:52
wpwrak_anyway, off to do some more shopping14:52
nicksydneycool...will experiment with it tomorrow 14:53
DocScrutinizer05nicksydney: just make DAMN SURE not to bring close to etching bath *any* solvents like acetone or other hydrocarbon stuff or liquids or objects that might contain such solvents15:23
nicksydneyDocScrutinizer05: ok sure...will be doing it in the garden away from all things15:24
DocScrutinizer05particularly nasty since acetone is a prominent solvent to remove toner etc from the PCB15:25
DocScrutinizer05you don't want acetone peroxide (apex) to build up in your etching bath15:26
wpwrak_could that even happen in the bath ?15:39
wpwrak_the peroxide is very diluted anyway15:39
wpwrak_should try that once, then. something to scare the dogs in the neighbourhood with ;-)15:40
DocScrutinizer05apex - the devil's granma15:40
DocScrutinizer05one of the rules set into granite of chemical labs: never bring acetone and H2O2 next to each other15:43
DocScrutinizer05no matter which concentration or how good the glas tube separating those two components15:44
DocScrutinizer05it's the same class of rule like "never oil oxygen bottle threads"15:45
DocScrutinizer05or "never pour water into acid"15:45
lekernelhow dangerous would be those small amounts, though?15:56
DocScrutinizer05well, when the hydrocloric acid explodes right into your face, you won't ask if it been 0.1 or 10g of apex that caused it15:59
DocScrutinizer05though I just read copper(ii) salts can stop the creation of acetone peroxides15:59
DocScrutinizer05lekernel: the amount will depend on how much acetone you add to the etching bath16:04
DocScrutinizer05and 10g of acetone peroxide are for sure no joke to handle16:05
DocScrutinizer05it's about as potent as nitro16:05
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