#qi-hardware IRC log for Tuesday, 2012-11-06

xiangfuhow can I count the vias in KiCAD?08:13
wpwrakxiangfu: in pcbnew, File > Fabrication Outputs > Drill (.drl) File. The dialog that comes up has the number of vias. (Then just cancel.)11:48
wpwrakhmm, does IRC have a "send when user returns" feature ? would seem useful when communicating with those who are not "always on", particularly when timeshifted11:50
viricnickserv has a mailbox11:51
viricwhen the nick identifies, gets notified of messages there11:51
virichm maybe it's not nickserv, but another freenode bot11:52
larscwpwrak: that's called email ;)11:53
wpwrakbah, that's so pre-social media11:53
viricwpwrak: it's memoserv.    /msg memoserv help11:54
larscwpwrak: twitter should work fine as well11:54
wpwrakviric: thanks ! let's see if it works :)11:55
viricmemoserv is both the past and the future!11:56
wpwraklarsc: hmm, or maybe open a linkedin account, invite the recipient, and let linkedin flood him with nag mails11:56
wpwrakviric: so you say xiangfu will have read the message i just sent now before he left some time ago ?11:56
viricI can't decode your message11:58
wpwrakthat was a reference to the past. ... yup :)11:59
wpwraksend message now, memoserv delivers it before it was sent.11:59
wpwrakviric: kewl, works :)12:00
viricamazing technology12:04
wpwrakthese fancy new "electronic brains" are quite something, eh ? maybe one day, they'll even play chess12:10
qi-bot[commit] Werner Almesberger: poke/: move over from svn.openmoko.org/developers/werner/poke/ (master) http://qi-hw.com/p/wernermisc/355614b12:11
paul_boddieOh dear: http://www.bbc.co.uk/news/technology-20219292 ("Imagination challenges ARM with Mips takeover")13:23
wpwrakthat may be good. other soc makers may be unwilling to license powervr if imagination are competing in the soc market.13:31
paul_boddieKnowing Imagination and their highly proprietary PowerVR stuff, this probably means that they want MIPS vendors to saddle their products with it.13:32
wpwrakxiangfu: you may have news from MemoServ ;-)13:32
paul_boddieObviously Intel, AMD and ARM have dumped Imagination, so they're effectively a patent troll in waiting.13:32
wpwrakif you see a patent, the trolls usually aren't far ...13:33
paul_boddieActually, AMD probably never used them, but now that AMD will also produce ARM-based products, it's almost reassuring that ARM seem to have dumped PowerVR. Then again, ARM aren't completely trustworthy.13:35
wpwrakfrom what i've heard, mali is somewhat open. not sure if that's thanks to ARM or thanks to good reverse engineers, though.13:37
xiangfuwpwrak, [File > Fabrication Outputs > Drill (.drl) File.] thanks. I got 577 vias.13:40
xiangfuwpwrak, how do I know if them are blind vias or buried vias?13:41
xiangfuwpwrak, do you remember, once you talking about 'azonenberg' fpga PCB board. that something is not easy for command pcb fab?13:43
xiangfusomething on azonenberg's board.13:43
xiangfuI have 2 azonenberg board kicad files here. one is 'minimal-spartan6-tq144 2 layers board', another one is xc6slx9 ftg256 4 layers board.13:44
paul_boddieWhat was the word on OpenRISC, by the way? I may go to a talk about that soon, and it'd be interesting to hear what people think of it in advance.13:49
wpwrakxiangfu: in general, you should try to avoid fancy vias. the best are through vias. then blind. buried are worst.13:54
wpwrakxiangfu: kicad doesn't seem to distinguish blind and buried in its statistics13:55
xiangfuwpwrak, ok. got it. I saw those fancy vias cost more money in PCB fab. :-)13:56
wpwrakxiangfu: azonenberg designs his boards to the capabilities of his pcb house. so you have to be a bit careful with his designs. they may be more demanding than necessary for a given design.13:57
wpwrakfancy vias also restrict your choice of fabs. and they're harder to debug if anything goes wrong.13:57
wpwraks/for a given design/for a given circuit/13:58
xiangfuwpwrak, what is the special design?13:59
wpwrakwhat i mean is that he does some things in ways that complicate producing a board. that may include difficult via types or very narrow mechanical tolerances.14:02
Action: paul_boddie is looking at http://opencores.org/or1k/Ordb2a-ep4ce2214:02
xiangfuwpwrak, also there is a 'Impedance Control' like 10% or 5%. is that very important for 4 layer board?14:03
wpwraki do the other extreme :) my boards are generally meant for DIY, so all vias are very simple, there's a lot of mechanical tolerance, etc.14:03
wpwrakdepends on whether you have signals that need to be impedance matched :)14:03
wpwrakthings like RF or other high-speed signals14:04
xiangfuwpwrak, (impedance matched) ok. what is the Impedance control on m1 board? do you know that?14:05
wpwraknot sure if any impedance constraints were specified for M1. most of the signals there are slow. you'd have to ask adam.14:06
xiangfuok. then I think I also don't need that at all. :-)14:06
wpwrakwith your little FPGA board ? no, i hope not ;-)14:07
xiangfuwpwrak, last question. how do I know the 'Min Annular Ring' on KiCAD?14:07
xiangfuevery vias cost money. :(14:07
xiangfuabout the Thickness (Finished Board), most common 2 or 4 layer board is 1.6mm. right?14:09
xiangfusome RF board may need 0.8 or 1mm PCB board.14:09
wpwrak(annular ring) that's a question from your pcb fab ? it would be either the outer diameter of vias or the difference between inner and outer diameter. not sure which.14:09
wpwrak1.6 mm is very common, yes. for small boards, you can also pick thinner pcbs. but 1.6 mm is a good default choice.14:10
xiangfuwpwrak, this is the board full detail asked by PCB fab: http://pastebin.com/BNPK0vXu14:10
wpwrakthey could get some of the parameters simply by processing your files ...14:13
wpwraki guess they're lazy :)14:13
xiangfuyes. good thing is I learned something on those questions. :-)14:14
xiangfualso for calculate the order price before I send the Gerber files14:16
Action: paul_boddie notes fairly recent slides, video, audio about OpenRISC at http://opencores.org/or1k/OpenRISC_Project_Meeting14:17
wpwrakyour vias seem a bit odd. the drill is quite large (0.3 mm / 12 mil) but the ring is narrow (only 0.1 mm)14:18
wpwraki would make the hole a bit smaller (e.g., 0.25 mm / 10 mil). maybe also grow the ring a bit, in case you want to make DIY board from these parameters.14:19
xiangfuhmm... 14:28
xiangfuin kicad. the Via shows: Diam: 0.551mm, Drill 0.330mm. 14:28
xiangfuis that means ring is 0.22mm14:29
wpwrak0.22m / 2 for the ring width 14:31
xiangfuoh. yes. 0.22 / 2 14:31
xiangfuthanks wpwrak. I think I understand all those PCB Specification now. :)14:38
wpwrakkewl :) good luck with the board !14:40
qi-bot[commit] Werner Almesberger: ioscript/: script-based toggling of IO pins (for device testing) (master) http://qi-hw.com/p/ben-blinkenlights/025726e15:06
wpwrakcool. i made a line with led so bright that i still have afterimages about a minute after looking at them ;-)16:33
larscnot cool...16:46
wpwrakand was only at about a third of the maximum brightness :)16:57
whitequarkwpwrak: it should be quite hot actually20:04
wpwrakthe board gets a little warm indeed20:06
whitequarkas per afterimages20:07
whitequarkonce I tried to make a photo of myself with my smartphone20:07
whitequarkand due to lightning conditions in the room, I had to do it with flash20:07
whitequarkit was quite literally painful20:07
whitequarkand I wasn't able to open my eyes for at least 30 seconds after clicking the button20:08
whitequarkI think that flash can be used as a weapon20:08
whitequarkyou can lit up a medium-sized room with it well enough to comfortably read 12-15pt text20:09
viricare LED flash common?20:12
whitequarkviric: almost any modern smartphone has one20:13
whitequarkthrough not every one of these is as powerful of mine20:13
whitequarkI think that samsung went a bit overboard20:13
viricdo they use high voltage?20:13
whitequarkfsvo high20:13
whitequarkI think that the led is actually a compound one, with 4 or maybe 6-8 dies20:13
whitequarkfrom what I know about bright LEDs20:14
whitequarkthey're connected sequentally, hence you'd need voltages in range of 10-20V to power it20:14
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