#qi-hardware IRC log for Saturday, 2015-09-12

whitequarkhey DocScrutinizer05, does neo900 support UMTS/LTE bands in use in Hong Kong?06:54
whitequarkthat is, UMTS 850, UMTS 900, UMTS 2100 and LTE 1800, LTE 2300, LTE 260006:55
whitequarkohh crap, the US/EU is an either-or and the modem is soldered down06:55
whitequarkguess i am not getting one after all :/06:56
wpwrakwhitequark: partially ... http://neo900.org/faq#networks06:57
whitequarkyeah it's like... i foresee being in US, EU and HK a lot going forward and my current phone only had LTE in EU and EDGE in US and nothing in HK06:58
whitequarkit was a deeply unpleasant experience06:58
whitequarkto be fair, there are like twenty LTE bands and they're all over and it's an extreme clusterfuck06:59
wpwrakyes, UTMS is bad, LTE worse. i love my GSM ;-)07:01
whitequarkyou do realize in many places it's not deployed anymore, right?07:02
whitequarkHK has data over neither UMTS nor GSM07:02
whitequarkUS doesn't have data over GSM07:02
wpwrakbut telephony ?07:02
whitequarktelephony, yes, I could not possibly care less about calls. I don't call people07:02
wpwrakah :)07:02
whitequarkfor several reasons, including: many of my peers don't disclose their cellular number bc of very practical privacy concerns07:03
wpwrakfor data, i use WLAN. data over telephony is usually economical suicide.07:03
whitequarkif the data you transmit is mostly text...07:03
wpwrakah yes, reveal thy number and there will be a drone homing in on you soon ...07:03
whitequarkor a bunch of angry gamers. but yes.07:04
eintopfhttp://wavedrom.com/ - when you need to daw clock diagrams07:18
wpwrakeintopf: cute :)08:59
DocScrutinizer05WOW, never seen before: https://www.google.com/url?q=http://home.jeita.or.jp/page_file/20110517171451_cub9MvYFEh.pdf&sa=U&ved=0CBQQFjAAahUKEwjn1rOM5vHHAhWCShQKHbZ-BY4&usg=AFQjCNHB1q1Dueo14Cy3pBAGoQUb34Vuzg15:25
DocScrutinizer05LiIon generic safety requirements (also for dis/charging) form Japan $entity15:26
DocScrutinizer05seems sorta authoritative15:27
DocScrutinizer05krhrhrhr >> To prevent hot electrolyte steam emitted from a gas-releasing vent to be staying in the battery enclosure and to catch fire, it is imperative that an electrolyte steam outlet is prepared. Such outlet should be positioned to allow the steam emitted to be directed away from the user.<<15:33
DocScrutinizer05ROTFL @ >> If the circuit board is provided with a storage device storing the operating status of the battery, arrange the board so that the storage device is located away from the cell. This is to ensure that the stored data is protected from the influence by the heat generated in the event of a battery fault.<<15:35
DocScrutinizer05as if anybody would be interested in the stored status info of an exploded battery ;-P15:36
whitequarkactually, that would be useful when you do root cause analysis19:53
DocScrutinizer05hmm, mildly20:03
DocScrutinizer05you can tell charging status by strength of explosion ;-P20:04
DocScrutinizer05anyway I don't see how this is a mandatory design requirement for all batteries20:05
DocScrutinizer05on the same level of importance like first quote up there20:05
DocScrutinizer05about electrolyte steam emitted20:06
DocScrutinizer05they have a few more such quite reasonable requirements like thermal isolation between cells of battery, etc. I can't see how this nonsense to protect the status storage chip from overheating in case of fatal battery failure helps preventing the battery to fail20:07
DocScrutinizer05or contributes to the security of that battery at large20:07
whitequarkI am quite sure it is there to help doing RCA20:08
whitequarkdo batteries fail early in life? what was the min/max temperature? etc20:08
whitequarkand these are just parameters any random charge controller will record, not even one specifically designed to be useful for RCA20:08
DocScrutinizer05how's a battery supposed to even fail? all the other requirements are made to ensure it doesn't, in a way that would destroy anything20:09
DocScrutinizer05it's a pretty silly requirement anyway20:10
whitequarkleft out in the sun? puncture?20:10
DocScrutinizer05I won't send in such battery remnants for forensics to the battery manufacturer20:10
DocScrutinizer05and battery manuf isn't interested in doing any forensics on them anyway20:11
whitequarkthat's assuming you already know the cause20:11
whitequarktemp stats will allow to distinguish between those two20:12
DocScrutinizer05ohmy, how's that an item for a generic battery saftety requirements whitepaper?20:13
whitequarkI think anything that can fail and seriously injure someone /must/ be amenable to RCA of failure20:13
DocScrutinizer05aha! so they should have made that chip mandatory20:14
whitequarkthat would make sense, yes20:14
DocScrutinizer05in everything, not just batteries20:14
whitequarkwell, a PCB failing won't lead to that20:14
whitequarkyour shitty phone just stops to work. no big deal20:15
DocScrutinizer05aha, even when that PCB is for example controlling your car engine or steering?20:15
whitequarkno, sure not, cars fall into the same category as batteries20:16
DocScrutinizer05yet nobody ever asked for such recording chips in the engine controller20:16
whitequarkshould've said "well, most PCBs failing won't lead to that"20:16
DocScrutinizer05neither in the car battery which nowadays also often is LiIon20:17
whitequarkhuh? doesn't a LiIon car battery fall under the exact whitepaper you're citing?20:17
whitequarkbut yes, I would definitely expect a car /battery/ have such a facility, regardless of chemistry, and a car in general20:17
DocScrutinizer05yes, however it usually doesn't have any such status recording chip I'd know of20:18
whitequarka car already has a shitton of sensors, and definitely you should log everything into a 'blackbox'20:18
DocScrutinizer05it's supposed to work and nobody even cares about charging state20:18
whitequarkI know for a fact some cars have pretty advanced blackboxes20:18
whitequarkthat include things like hydraulic pressure, steering position, engine stats and yes battery charge20:18
DocScrutinizer05tzz, never seen a car battery with more than 2 poles20:19
whitequarkoh, you mean a lead-acid battery in a non-electric car20:19
DocScrutinizer05so yes, your car blackbox might record the voltage of battery20:19
whitequarkthose don't really fail hazardously, do they? except in a collision or something, where all bets are loose20:19
DocScrutinizer05exactly, they are supposed to work and nobody cares if it's lead acid or LiIon20:20
whitequarkwell no there is a large difference20:20
whitequarkLiIon supports a runaway reaction that leads to explosion, lead acid doesn't20:20
whitequarkLiFePO4 also doesn't and you know what? there is no limitation on amount of LiFePO4 batteries you can take or ship in an aircraft20:21
whitequarkexactly because of that20:21
DocScrutinizer05yes, and still no external monitoring and most likely no internal monitoring and recording either. They simply are supposed to work and never ever fail20:21
whitequarkthat's consistent with everything I said above I think?20:22
DocScrutinizer05well, when you mix stuff then yes. I talked about LiIon, not LiFePo20:22
whitequarkthen let me summarize: LiFePO4, lead acid don't fail hazardously, no monitoring. LiIon does, has to have monitoring20:23
whitequarkseems right to me?20:23
DocScrutinizer05my point stands: it's silly to require a disaster-hardened recorder chip without making that recorder chip a mandatory feature to start with20:24
whitequarkoh, yes20:24
whitequarkit doesn't?20:24
DocScrutinizer05>>**If the circuit board is provided** with a storage device storing the operating status of the battery, arrange the board so that the storage device is located away from the cell.<<20:25
whitequarkwell that's just... bullshit20:26
DocScrutinizer05and that in a generic wqhitepaper about battery security requirements20:26
DocScrutinizer05exactly, just bullshit20:27
DocScrutinizer05some dude had a momentary hiccup20:28
DocScrutinizer05or rather cerbral brownout20:29
DocScrutinizer05it's a 'nice to have' at best, at the discretion of the particular battery manuf20:31
DocScrutinizer05"dear designer, when you already add a recorder to your battery, consider added benefit fron placing it in a position where it will survive disasters. You'll love the forensic options it offers"20:32
DocScrutinizer05that's stuff for an EE 101 book, not for a generic semi-official whitepaper about security requerements20:33
DocScrutinizer05or maybe they meant "battery failure" == simple overtemperature, where the battery could recover from. And you wouldn't want such "failure" to damage the status recorder and that causing secondary induced disaster20:35
whitequarkI'd imagine anything that kills the IC or even the flex cable will destroy the battery very well20:36
whitequarkit's well over 100 and even 15020:36
DocScrutinizer05however that's already covered by their other policies, like "no single point of failure"20:36
whitequarkwait, what20:37
whitequarkhow the fuck does that work20:37
whitequarkI'm not sure I have ever seen a battery satisfying that design20:37
whitequarkmaybe those larger car ones, I dunno, definitely not in small electronics20:37
DocScrutinizer05no single fault fail?20:38
whitequarkoh, or do they mean like20:38
DocScrutinizer05all devices are supposed to have at least 2 independant security means20:38
whitequark"you need both a temperature sensor AND an overcurrent sensor failure"?20:38
DocScrutinizer05no, they mean "when FET in electronic security fails, there still needs to be a blowfuse to kick in"20:39
whitequarkah alright20:39
DocScrutinizer05no single point of failure scenarios20:40
DocScrutinizer05that can't get handled by another subsystem20:40
DocScrutinizer05in the usual smartphone you have at least 3 independant security mechanisms20:41
DocScrutinizer05the standard high level charger, plus a electrinics and a PTC or whatever in the battery itself20:42
DocScrutinizer05often the phone also has an additional fuse in batery rail20:42
DocScrutinizer05cheap chinese chargers rely entirely on the electronics in battery to avoid overcharging20:43
whitequarkyeah I've seen those20:43
DocScrutinizer05which is a damn poor design20:43
whitequarkone of them was USB5V connected via a diode20:44
DocScrutinizer05great! ;-P20:44
DocScrutinizer05I've seen one charger that literally consisted of a plastic case, two springs for battery, two steel poles for mains jack, two capacitors and a Graetz bridge20:45
DocScrutinizer05*nothing else*20:46
whitequarkthe capacitors form a divider?20:46
DocScrutinizer05series impedance for both mains poles20:46
DocScrutinizer05basically you had Live voltage on both battery contacts, mitigated by a series 1uF or something20:47
whitequarkyeah that's so fucked up20:48
DocScrutinizer05I really thought that must be a bad joke or something20:48
whitequarkthat's depressing20:49
DocScrutinizer05for such "charger" any battery internal electronics will fail epically since they can't cope with dunno 110V or even 230V20:50
DocScrutinizer05I guess that crap must have been 19 pence on some chinese "whatever you search for, here you'll find it" shop or market20:51
DocScrutinizer05and the guy who designed and marketed that crap maybe killed a few dozen people with it, but for sure made a million and had no problems whatsoever20:52
DocScrutinizer05I bet same shop sold a plug with cable with two blank wire ends as a water heater20:54
whitequarkyou can put an unsafe razor blade between those. some people legit make heaters like that20:55
DocScrutinizer05"to speed up cooking, add some salt to water"20:55
whitequarknow it's sharp, hot AND under voltage20:55
DocScrutinizer05called "Moped" in german jail20:56
DocScrutinizer05tobacco is caled "Koffer"20:56
DocScrutinizer05seems they have a special language in jail20:57
whitequarkyeah, jail jargon20:57
whitequarkor more like prison20:57
whitequarkdoes 'normal' german have a lot of loanwords from prison jargon?20:57
DocScrutinizer05hmm, I probably can't know, but I also don't know of many20:58
whitequarkrussian sure does. not surprising given the amount of people who were in camps. 1/3 of population at some point, I think20:58
DocScrutinizer05maybe formerly "Heierman" for a 5 DM coin20:58
whitequarkand a good deal of those loanwords are now just everyday words20:58
DocScrutinizer05in certain social groups it's naturally a lot more20:59
whitequarkI mean like middle class21:00
DocScrutinizer05those groups that form outside of prison but all the members are highly likely to end in prison eventually21:00
DocScrutinizer05I just wonder where the heck they get razorblades in prison21:01
DocScrutinizer05sounds like the last thing I'd make available in prison21:01
whitequarksmuggle inside by using body color band-aid to tape it to your body?21:02
whitequarkwell, that's the apocryphal story21:02
whitequarkthings get smuggled into prisons all the time21:03
DocScrutinizer05never been in real prison, only several weeks in "Untersuchungshaft" when they arrested hundreds of people who happened to be wrong place wrong time21:04
DocScrutinizer05I was evidently the one person who arrived there late and so wasn't involved in the reason of mass detention. And I was the last to go free since what I said had happened was "impossible to have happened" according to police :-S21:06
DocScrutinizer05so everybody who said "yes, I joined that demo but I didn't throw stones" went free. While I said "I wasn't on the demo and enetered the building when it was already surrounded by police" had no plausible alibi21:09
DocScrutinizer05shit happens ;-)21:09
whitequarklesson: don't tell truth to authority, tell them what they want to hear :p21:10
DocScrutinizer05(lesson) yes, usually that works. In this particular context however I knew of only one thing they wanted to hear: "Yes, I'm a terrorist"21:16
DocScrutinizer05I think they paid me 5DM per day of that 4 weeks illegal detention, after a year and some21:17
whitequark4 weeks! wtf21:18
DocScrutinizer05toldya, I was the last to go free21:18
DocScrutinizer05except those few they actually knew were throwing stones21:19
DocScrutinizer05http://www.spiegel.de/spiegel/print/d-14318869.html 21:22
DocScrutinizer05anyway since then I have my very own take on politics and state21:49
DocScrutinizer05and a somewhat fraught relation to police21:49
DocScrutinizer05not like this came out of thin air, situation and (political) mood been similar before and after the "detention of 141", and I didn't exactly love police before that already21:52
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