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<nicksydney>
just read the blog from Pyra and it is 8 layer board damn !
<nicksydney>
the same like Neo900
<nicksydney>
anything more than 2 layer for me is awesome
<nicksydney>
:)
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<DocScrutinizer05>
hey, N900 is 10 layer, it seems (I didn't disclose the photos I _tried_ to shoot from my cut out bare PCB where I slightly cut into the PCB active area and it seemed under mag glass like a two times 5 layers showed on the edge)
<nicksydney>
wow..10 layers...blown away :)
<nicksydney>
what do they have on each layer....i know that one of the layer must be a ground layer
<nicksydney>
the components are soldered on top and bottom right ? so that's 2 layer taken and 1 layer for gound ..so that's left with 7 layers ..am i correct ?
<DocScrutinizer05>
I might have missed to count the two outermost layers ;-)
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<wpwrak>
with so many layers, that board will be hell to produce ...
<wpwrak>
very limited choice of factories, high cost, endless lead times, ... i have fond memories of when openmoko went crazy on their pcbs as well ... and then the one fab that could actually make them closed ...
<wpwrak>
i suppose you have buried vias and such as well ?
<DocScrutinizer05>
please reread
<DocScrutinizer05>
8 layer used in N900 is pretty much standard
<DocScrutinizer05>
at least for 0.8+ mm FR4
<nicksydney>
DocScrutinizer05: so it's 8 layers not 10 layers ?
<DocScrutinizer05>
please reread
<DocScrutinizer05>
do you think i'd *guess* about the number of layers for neo900?
<DocScrutinizer05>
>><DocScrutinizer05> hey, N900 is 10 layer, it seems...<<
<DocScrutinizer05>
Neo900 is 8-layer
<wpwrak>
ah, good :)
<wpwrak>
it sounded as if you had ended up with 12 ...
<DocScrutinizer05>
the heck, it sounded *to you* like that
<wpwrak>
(guess) well, if the number gets large enough you could use some just to rounding errors ... ;-)
<DocScrutinizer05>
and no, actually I counted the suface layers on that N900 board
<wpwrak>
good :)
<DocScrutinizer05>
good? why?
<DocScrutinizer05>
does it matter in any way?
<wpwrak>
good for them and their sanity
<DocScrutinizer05>
I don't give a flying F about that
<DocScrutinizer05>
or rather, my notion about that latter is already quite dedicated
<wpwrak>
you should be nice to them. if you want, think of them as the little monkeys neo900 evolved from :)
<DocScrutinizer05>
they had some good EE staff and a real crew of douchebags for project managers or higher up
<wpwrak>
what's new ? ;-)
<DocScrutinizer05>
nothing really
<wpwrak>
actually, that's something i liked when openmoko took on the dash project: fic shut down fiwin, fired all the management that had screwed up things to royally, and only retained (a good number of) the engineers
* DocScrutinizer05
wonders if darlingtons with Ft:3GHz are commonly available nowadays
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<wpwrak>
qucs ... no spice for me, thanks ;-)
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<DocScrutinizer05>
that 100M resistor actually should be 47k * amplification_darlington * 20
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<DocScrutinizer05>
I'm afraid that the darlington basis acts like a rectifier which would create a negative bias on the 10pF, so the darlington would again operate "on the edge" after first 2 or 3 sine waves from input
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<DocScrutinizer05>
mmpf, my bouncer went offline
<wpwrak>
does your bouncer kick you out of the lab when you've had too much solder fumes ? :)
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<DocScrutinizer05>
no, it makes my N900 create funny clicking noises
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<DocScrutinizer05>
o.O
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<DocScrutinizer05>
wpwrak: maybe using a mosfet would avoid such rectifier effect creating negative bias on the 10pF DC-blocker capacitor?
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<wpwrak>
you're already way beyond my knowledge there :)
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<DocScrutinizer05>
it's pretty simple: when input is "high2, the 10pF will charge positive on input and negative on basis side, due to current flowing from input into basis-emitter diode(s). Now ehen input goes GND level or even negative, the capacitor will pull down the basis but no current will flow out of basis thru capacitor and series R to input
<DocScrutinizer05>
so the negative bias on darlington basis will sustain
<DocScrutinizer05>
effectively compensating the positive bias created by the 100M
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<DocScrutinizer05>
the inner 7 layers (4 copper, 2 thin and core thick isolation) make for the flex cable that connects the mainboard to the daughterboard
<DocScrutinizer05>
at least I guess how it's built
<DocScrutinizer05>
at least I guess that's how it's built
<xiangfu>
wpwrak: Hi I just find him on IRC and another email address.
<xiangfu>
have you try message him by IRC?
<nicksydney>
DocScrutinizer05: sorry for stupid question but when you say N900 are you referring to Neo or Nokia ?
<DocScrutinizer05>
N900 is Nokia
<nicksydney>
gotcha...that's why i was confused back and forth :)
<DocScrutinizer05>
Nokia never built a Neo device
<nicksydney>
both has got the N infront so just want to make sure
<nicksydney>
and both has the 900 too :)
<DocScrutinizer05>
and both look damn similar
* DocScrutinizer05
wonders WTF for are those pads above "E" key
<DocScrutinizer05>
they are unused in N900
<DocScrutinizer05>
err, actzally above "W" key
<DocScrutinizer05>
(3rd from left, upper row)
<nicksydney>
no idea :
<nicksydney>
:)
<nicksydney>
this Nokia pcb design is available ?
<DocScrutinizer05>
err, available?
<DocScrutinizer05>
please rephrase!
<nicksydney>
the files .. the schematics like neo900
<whitequark>
headline translation: "Tolyatti citizen went to Ivanovo, lost his ID, came to visit a retiree, then died and decomposed. / Meanwhile, the retiree continued drinking."
<whitequark>
6 mil = .15mm; 4 mil = .1mm; 2 mil = .05mm
<whitequark>
mil is 1/1000"
<viric>
ah
<viric>
thank you
<whitequark>
np
<DocScrutinizer05>
I heard you can flatten gold to around 5 atom layers thickness ;-P
<whitequark>
DocScrutinizer05: is that your friendly way of saying "overkill"? ;)
<DocScrutinizer05>
hmm, looking at that sample, it's probably not
<whitequark>
nevermind the defects in it, it's random dust and not really related to process
<whitequark>
dust and/or shitty negative. neither matters for what I'm working on now
<DocScrutinizer05>
aah, then
<whitequark>
but the .1mm line *is* broken in a lot of plces
<whitequark>
and .05mm is simply absent
<whitequark>
I've actually had it on earlier samples, dunno why that stopped working while everything else improved
<DocScrutinizer05>
well, in that range you already need to compensate for undercutting
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<whitequark>
I still have a few ideas to try; soaking board in NaOH for 10min to remove all organic crap from it; using lowest grit sandpaper for better surface finish and contaminant removal
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<whitequark>
(undercutting) yeah... copper thickness is .035mm
<whitequark>
so .05mm actually hardly makes sense there
<DocScrutinizer05>
photoresist thickness
<whitequark>
oh?
<DocScrutinizer05>
light diffuses in photoresist as well
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<whitequark>
diffuses, hmm...
<DocScrutinizer05>
gets reflected from copper
<whitequark>
you know what, let me measure the actual line width I have there. the photo is almost perfectly parallel to camera sensor so it's easy
<DocScrutinizer05>
doesn't come in ideally parallel
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<whitequark>
right.
<DocScrutinizer05>
toner tends to build heaps
<DocScrutinizer05>
so isn't plane
<whitequark>
no, that was taken care of with "toner density"
<whitequark>
the actual trace widths are often off by .05-.1mm depending on their position
<whitequark>
the centermost trace is really damn wide
<whitequark>
I need to make a better light source
<whitequark>
DocScrutinizer05: also, thickness of developed resist is somewhere around .04mm if I'm using my caliper right
<whitequark>
so .05mm trace means it would be almost rectangular in section! no wonder it doesn't work well
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<DocScrutinizer05>
:nod:
<DocScrutinizer05>
with copper you'll get similar problems
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<DocScrutinizer05>
you need to control your etching process a factor 50 better than you're able to do right now, to etch a 0.05mm wide trace into standard FR4 material
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<DocScrutinizer05>
copper fpild for up to 1.55mm are generally 17µm it seems
<DocScrutinizer05>
foils*
<DocScrutinizer05>
but then you start to have 35 or even 70µm
<whitequark>
DocScrutinizer05: it's 35µm I have here
<whitequark>
at least the vendor claims it's 35
<whitequark>
"1 oz" translates to 35µm afaik
<whitequark>
yeah, it does
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<roh>
35 is 'normal' for hobbyists stuff
<roh>
if you produce pcbs professional its much thinner and they make it thicker only after the first round of etching
<roh>
to reduce the amount of needed copper (expensive)
* whitequark
nods
<roh>
but afaik the processes needed arent feasible at home.. so.. we have simple 35µ from the start
<whitequark>
roh: I think they're pretty feasible, I've encountered that while researching whether I can set up electroplating
<whitequark>
it's just a CuSO₄ bath
<whitequark>
and a lot of current
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<roh>
i see... well.. send pix if you done it ;)
<whitequark>
electroplating holes or whole boards?
<roh>
both
<whitequark>
I've been thinking to cover everything except vias with resist and then electroplate only to holes
<whitequark>
simply because this way it's much quicker; I don't need to cover the entire board, just tiny vias
<whitequark>
sure
<whitequark>
I'll document it thoroughly, too
<whitequark>
what I really want is not a quick hack but a reproducible process, if only for sake of understanding how exactly to set up such a process
<roh>
yeah. also what to do with the waste
<roh>
thats what kept me off all this chemical stuff most the time. waste disposal is really tricky to do well
<wpwrak>
with HCl+H2O2 you produce nearly zero waste
<wpwrak>
and if you want to get rid of some, leave it outside so the water evaporates and you're left with solid residues
<whitequark>
roh: waste? which waste?
<whitequark>
CuSO4 bath doesn't have any. it deposits copper ions from electrodes to solution and then from solution to PCB
<whitequark>
the electrolyte can be used indefinitely
<whitequark>
other chemicals I use... NaOH, K2CO3 can be poured down the drain in any part of world
<whitequark>
pure (NH4)2S2O8 is benign (it'll immediately oxidize some organic and will turn into harmless ammonia and sulphate anions)
<whitequark>
used (NH4)2S2O8 with copper cations is worse, but honestly that miniscule amount of copper is not going to do anything, no matter how greenpeace wants you to think otherwise
<whitequark>
also consider that in Norilsk factories probably dump dozens of tons of copper a year
<whitequark>
*shrug*
<whitequark>
if I was really concerned about the whopping 20g or so of copper I'd need to dump when I use all of this solution, I'd add NaOH to it, after which insoluble Cu(OH)2 will precipitate
<whitequark>
that last thing can be thrown to landfill, it's not going to enter water stream.
<whitequark>
roh: I suspect your local bureaucracy would be tougher than actual safe waste disposal
<roh>
yep... well.. its rather a question of honor i guess ;)
<roh>
atleast in the amounts we use for hobby.
<whitequark>
sure. I think you've actually convinced me to dispose of it properly, considering I see how it is not hard at all
<whitequark>
just some highschool chemistry and you're done
<whitequark>
wpwrak: I've recalled another argument against HCl+H2O2
<whitequark>
it's a good way to get you some chlorine gas and that is going to corrode all iron tools you have around
<whitequark>
I've actually screwed up like that once and some of my tools are still rusty from that incident
<whitequark>
the thing is, you don't even need that much Cl2. tiny amounts still do have impressive effect on anything Fe or Cu or even plastics
<wpwrak>
yes, that's why i store it outside and open the bottle near the window. the etching doesn't produce much Cl gas.
<whitequark>
call me weird but I still prefer "no chlorine" over "a little chlorine"
<whitequark>
huh. I found a vendor who sells 12kg of H2O2 for $13
<whitequark>
and they apparently work with individuals
<wpwrak>
nice price. what concentration ? 0% ? :)
<whitequark>
30-40% apparently
<roh>
no chlorine is nice. the broken tools really suck
<roh>
it even makes aluminium really ugly
<whitequark>
wpwrak: I've googled it and it seems to be a common price for H2O2 here
<whitequark>
another vendor sells 34kg drums for ~$30
<whitequark>
roh: it just ruins everything it touches :/
<whitequark>
huh. "Metallic Na 98%" $50/kg
<whitequark>
"H2O2 33%" $3/kg (retail price here)
<whitequark>
"Bromine" $20/l
<whitequark>
I really hope they do check whoever they sell this stuff to
<wpwrak>
30-40% is good. don't forget to wear gloves also when opening/closing the bottle or next summer you'll have to work extra hard to develop a tan :)
<whitequark>
yeah I'm using gloves all the time. mainly to not leave fingerprints currently, as none of the stuff I use is corrosive
<whitequark>
"Nitric acid, concentrated" $3/kg
<whitequark>
"Aluminum, finely ground" $15/kg
<whitequark>
this is a real treasure of a vendor
<whitequark>
hydrazine!
<whitequark>
how is shipping that even legal
<wpwrak>
you should ask them if the have activated FOOF on tap ;-)
<whitequark>
they don't seem to stock nonexistent or absurd stuff. it just seems awkward in wake of recent regulations
<lekernel>
do they have dimethylmercury?
<whitequark>
no
<lekernel>
a few years ago there were plutonium listings on alibaba.com
<lekernel>
they seem to have disappeared
<whitequark>
yes, I'm talking about that kind of stuff.
<whitequark>
this shop doesn't have anything with mercury at all
<whitequark>
"Disprozium" $5300/kg
<whitequark>
"Europium(III) oxalate" $2400/kg. they seem to stock quite a bit of rare-earth stuff
<whitequark>
um, "Heavy fluid" $30/kg
<whitequark>
what?
<whitequark>
heavy fluid ?
<wpwrak>
try to order some of their nastier stuff. see if they let you. maybe they just forgot to update their shop. or require clients to show some credentials.
<whitequark>
wpwrak: nah don't want to. I'll probably get put (and rightfully so) onto some bozo list
<wpwrak>
(heavy fluid) they'll add more details once someone has ordered it and they autopsy results come out
<wpwrak>
well, then get something difficult but harmless. like a small quantity of HCl :)
<whitequark>
(heavy fluid) I missed the standard#; it's actually concentrated Ba(CdI)4 solution
<whitequark>
used for ore flotation or something
<whitequark>
the standard makes reference to similarly generic properties of fluid. for example, "Colority factor (max) -- 60"
<whitequark>
WTF is a "colority factor" and why does it not even have units
<wpwrak>
not everything has a unit ;-)
<lekernel>
whitequark, do you happen to know where to find cadmium-109?
<whitequark>
>HALF-LIFE: 464 days
<whitequark>
you must be an international terrorist or something
<lekernel>
been looking at it for a while, also asked a couple professional physicists
<wpwrak>
breaking news: russian scientists reveal: "quantum theory is measurement error"
<lekernel>
no one could point out an obvious flaw
<lekernel>
also, it seems true that no one has experimented with gamma rays
<lekernel>
the shortest wavelength reported seems to be in the x-ray
<wpwrak>
whitequark: your next myth to debunk should then be dark matter. that would leave dark energy and maybe for dessert relativity. once you're done with that, newton can safely rise from his grave
<whitequark>
I know a guy who claims to have successfully homebrewed one
<whitequark>
hehehe, "Silicium(II) oxide" $15/kg
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<wpwrak>
whitequark: bah, gps is basic geometry. euclid could have designed it.
<whitequark>
wpwrak: surely you know it has corrections for both SR and GR?
<whitequark>
btw. I ordered the chemicals required for activating the holes for electroplating
<whitequark>
let's see how it goes
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<wpwrak>
whitequark: (gps) i didn't say that his design would have worked ... at least not without adding a few layers of epicycles and such ;)
<whitequark>
hehehe
<whitequark>
I wonder if you can model Lorentz contraction with epicycles or somesuch
<whitequark>
probably not
<wpwrak>
oh, i'm sure you ca
<wpwrak>
n. at least to any precision you want ... :)
<wpwrak>
("sure") not in the "i've proven it or saw someone prove it" kind of sense but more in the "if someone descends to that level of madness, it's inconceivable that they won't find a way that makes sense at least in their head"