2014-06-12 00:01 wej_ has joined #qi-hardware 2014-06-12 00:03 wej has quit [Ping timeout: 252 seconds] 2014-06-12 00:08 wej_ has quit [Ping timeout: 245 seconds] 2014-06-12 00:10 wej has joined #qi-hardware 2014-06-12 00:34 wolfspraul has joined #qi-hardware 2014-06-12 00:39 wolfspraul has quit [Ping timeout: 272 seconds] 2014-06-12 00:44 ooooh, transistor failure modes, now it gets interesting 2014-06-12 01:01 just when you thought they were invulnerable ? ;-) 2014-06-12 01:02 wpwrak: not quite, I was fully expecting something weird 2014-06-12 01:02 but I really want to understand how exactly did it fail 2014-06-12 01:02 it's no fun otherwise 2014-06-12 01:21 ah, so you blew it up. you did add the diodes ? :) 2014-06-12 01:22 of course not, told you so! 2014-06-12 01:23 I'm adding them now though, since I understand how and why it failed 2014-06-12 01:24 ;-)) i did warn you when you mentioned the schematics, though :) 2014-06-12 01:24 I remember 2014-06-12 01:24 I thought about it even when designing it, but it was probably too late and the rational voice was ignored 2014-06-12 01:25 anyway, it's even good that it failed, since I now understand it better 2014-06-12 01:25 another thing: 1) my homebrewn boards stand up to rework pretty well (no delaminated traces) 2) investing in solder mask was wise 2014-06-12 01:25 at least your experience puts the lingering question to rest whether this protection is really needed or whether we all just add it because "that's what one has to do", but it would actually be fine without it :) 2014-06-12 01:25 exactly 2014-06-12 01:27 (rework) well, they better do :) even on my little anelok board i replaced the OLED with its wide FPC twice already, without a problem. (FPCs are fragile critters and don't like a lot of mechanical abuse, so while they were just flapping freely, their life was intense and short) 2014-06-12 01:33 huh, yeah, both transistors are broken down entirely 2014-06-12 01:33 conductive between any pair of pins 2014-06-12 01:39 whitequark the transistor slayer ;-) 2014-06-12 01:41 ummmm 2014-06-12 01:41 I took a brand-new bc547 and C-E are shorted 2014-06-12 01:41 wat? 2014-06-12 01:41 I'm fairly sure this is not how transistors are supposed to work 2014-06-12 01:45 oh, nevermind, it was my error 2014-06-12 01:45 and such a stupid one I'm not even going to say which 2014-06-12 01:46 (wat?) you don't know the tv series "buffy the vampire slayer" ? 2014-06-12 01:46 ah, new transistor. i see 2014-06-12 01:46 "wat?" was about the shorted C-E pins 2014-06-12 01:46 * whitequark looks away 2014-06-12 01:47 I put it into the breadboard, completely forgetting that *solderless* breadboards have rows of shorted pins 2014-06-12 01:47 been years since I touched one 2014-06-12 01:47 :) 2014-06-12 02:03 nope, after adding diode it still does not work, with almost exact same symptoms 2014-06-12 02:03 and the transistor seems fine, or at least the Vf of both junctions is the same as for new 2014-06-12 02:03 and it's not broken down 2014-06-12 02:05 so basically... initially, Vbe=1.3, Vce=8.7. after feeding a pulse to base, Vbe=0.6, Vce=8.0 2014-06-12 02:05 and the relay is on 2014-06-12 02:16 your transistors are NPN or PNP ? 2014-06-12 02:19 in any care, your Vbe looks quite wrong :) 2014-06-12 02:19 #s/care/case/ 2014-06-12 02:24 npn 2014-06-12 02:29 * whitequark scratches his head 2014-06-12 02:29 what are you trying to send down Vbe ? 2014-06-12 02:30 um? 2014-06-12 02:30 i mean what levels are expected on the base ? on = xxx V, off = xxx V ? 2014-06-12 02:31 oh 2014-06-12 02:31 (before the resistor) 2014-06-12 02:31 0/5V 2014-06-12 02:31 so the initial 1.3 V should be 0 V 2014-06-12 02:31 yes 2014-06-12 02:31 and when you turn it "on", the base voltage drops. remarkable ;-) 2014-06-12 02:31 I mean, I measure 1.3V with base floating 2014-06-12 02:32 a floating base means nothing :) 2014-06-12 02:33 so I've tried to look up a commercially sold kit with a similar circuit, they have a resistor divider at base 2014-06-12 02:33 which makes 0.7V out of 5V, and also pulls it down normally 2014-06-12 02:33 a BJT is a current-defined device. as long as you have 0 current, your base could be anything (well, it will still settle to some value due to secondary effects) 2014-06-12 02:33 pull-down is a good idea 2014-06-12 02:34 wpwrak: (current-defined) sure 2014-06-12 02:34 what I mean is, I don't understand why it functions as a *latch* 2014-06-12 02:34 that just seems absurd 2014-06-12 02:34 it's not a FET, when the base is floating, it must do the same thing regardless of what I did to it before 2014-06-12 02:34 assuming it's not fried 2014-06-12 02:35 well, leave the base open (float) for now. then the relay is off, right ? 2014-06-12 02:35 yes 2014-06-12 02:35 now connect 5 V to the base (through resistor). then it should turn on. does it ? 2014-06-12 02:35 yes 2014-06-12 02:35 when you remove the 5 V and float again, does it turn off ? 2014-06-12 02:35 nope. 2014-06-12 02:36 fascinating :) 2014-06-12 02:36 *exactly* 2014-06-12 02:36 in russia, transistors have memory 2014-06-12 02:36 if you force the base to 0 V, what happens ? 2014-06-12 02:37 nothing 2014-06-12 02:37 relay stays on 2014-06-12 02:37 are you sure it's not a bistable relay ? 2014-06-12 02:38 one thing to check: are your transistor pins really where you think they are ? 2014-06-12 02:38 http://www.songchuan.eu/en/attachments/030_834.pdf 2014-06-12 02:38 http://us.100y.com.tw/pdf_file/TR99.pdf 2014-06-12 02:38 neither of these mention that it's "bistable" 2014-06-12 02:39 I am sure, I've checked it with a DMM and it has two junctions between the expected pins 2014-06-12 02:39 and it matches the DS 2014-06-12 02:39 also, I've tried desoldering the transistor and triggering the relay manually 2014-06-12 02:39 so it is NOT bistable 2014-06-12 02:41 ok 2014-06-12 02:41 forcing base to GND and still having the relay on is ... interesting 2014-06-12 02:42 did you connect to before or after the base resistor when forcing base ? 2014-06-12 02:42 connect to what? 2014-06-12 02:42 GND to base 2014-06-12 02:43 oh, tried either 2014-06-12 02:43 same result 2014-06-12 02:44 sequence: 1) all open. 2) apply power to system (relay off). 3) drive base through R to 5 V -> relay on. 4) float base (relay still on). 5) drive base to GND (relay still on). correct ? 2014-06-12 02:44 yea 2014-06-12 02:45 can you monitor the overall system current throughout all these steps ? 2014-06-12 02:45 with mA precision, yes 2014-06-12 02:45 for step 3, you can just use your system voltage (~ 9 V ?) so you don't need an external 5 V source 2014-06-12 02:46 24V 2014-06-12 02:46 "system" the transistor plus relay board. let's eliminate any driving circuit 2014-06-12 02:46 ah, quite high voltage 2014-06-12 02:47 ummm 2014-06-12 02:47 the current is... below what my adjustable PSU can measure 2014-06-12 02:47 use a multimeter :) 2014-06-12 02:47 but the relay needs 18 or so mA to stay on 2014-06-12 02:47 wtf 2014-06-12 02:49 more like 2 mA, i think (drop-out voltage) 2014-06-12 02:49 very interesting 2014-06-12 02:49 if I keep the base connected via a 2k resistor (in sum) to 24V, I see 2.5mA of current 2014-06-12 02:50 but the relay stays on either way 2014-06-12 02:50 what's the other way ? 2014-06-12 02:51 ewhether the base is connected or floating 2014-06-12 02:51 at 2.5 mA the transistor should let something in the order of 100 mA through. more than enough. 2014-06-12 02:51 ok, the PSU is lying 2014-06-12 02:51 it's 7mA just after turning it on 2014-06-12 02:51 maybe it's not floating when it's "floating" ;-) 2014-06-12 02:52 ... then 25mA while the base is high 2014-06-12 02:52 then back to 7mA 2014-06-12 02:53 what's your transistor's current gain ? 2014-06-12 02:53 7 mA should be plenty to keep the relay on 2014-06-12 02:53 it's bc547c, so 420..800 2014-06-12 02:53 but just not quite enough to _turn_ it on 2014-06-12 02:54 sure 2014-06-12 02:55 so you'd need about 10 uA on the base to turn the relay on. at 24 V that's about 2 MOhm. time to check for sneak current paths. 2014-06-12 02:55 how careful were you with cleaning the board from flux residues ? 2014-06-12 02:57 I didn't 2014-06-12 02:57 my DMM shows about 19MΩ to +24 2014-06-12 02:57 well, more like 40 uA, when we include the mystery 7 mA you start with. but that's still low enough for flux "connections" 2014-06-12 02:58 that still doesn't answer the question of why doesn't the relay turn off with base forced to 0 2014-06-12 02:58 one thing after the other ... 2014-06-12 02:59 disconnect power, connect base to GND, reapply power. what is the system current ? 2014-06-12 03:00 oh, and your diode goes across the relay ? or across relay and transistor, or something like this ? 2014-06-12 03:00 only across the relay coil 2014-06-12 03:02 good 2014-06-12 03:03 cleaned the board with dimethoxymethane, same result 2014-06-12 03:03 is system current is still high when starting with base to ground, then the next step would be to remove the transistor and see what happens 2014-06-12 03:04 since it behaves as if there was a path in parallel to the transistor 2014-06-12 03:04 the resistance went under what my DMM can detect 2014-06-12 03:04 well, I have second relay without the transistor 2014-06-12 03:05 on the same board, which behaved exactly same 2014-06-12 03:05 can check it 2014-06-12 03:06 you flux is friendly, being in the 10+ MOhm range. you ought to try one of the nastier ones some day, which go below 1 MOhm. they do great things to reset lines. 2014-06-12 03:06 ouch. good thing my PSU is current-limited 2014-06-12 03:07 * whitequark accidentally shorted it with DMM lead 2014-06-12 03:07 nice flash 2014-06-12 03:08 yes, that's why we use lab power supplies and always set the maximum current to something not too far above what we expect to need ;-) 2014-06-12 03:08 *facedesk* 2014-06-12 03:08 fuck. 2014-06-12 03:09 what was it ? :) 2014-06-12 03:09 you see, the board is nicely symmetric... 2014-06-12 03:09 +/- reversed ? 2014-06-12 03:10 oh no 2014-06-12 03:10 X1/X4 swapped 2014-06-12 03:10 it behaved like a latch because lol, I assembled a latch, essentially 2014-06-12 03:10 hmm, i don't have the schematics in sight 2014-06-12 03:11 http://i.imgur.com/c9LXLcS.png 2014-06-12 03:12 oh. hm. nothing changed. 2014-06-12 03:14 not sure how swapping X1/X4 would turn it into a latch ... well, if K1 is open, maybe fun things could happen with ground 2014-06-12 03:14 thought about that, yes 2014-06-12 03:14 oh. open 2014-06-12 03:14 well, nevermind, doesn't matter 2014-06-12 03:14 it's STILL a latch 2014-06-12 03:15 reliable russian technology. no matter how much vodka you had and where you connected things, it always works the same way 2014-06-12 03:17 but why is it a latch?!! 2014-06-12 03:18 did you do the base-to-ground-when-applying-power test ? 2014-06-12 03:19 xiangfu has joined #qi-hardware 2014-06-12 03:19 oh, and you have two K1 in your circuit 2014-06-12 03:19 and three K2 2014-06-12 03:20 wait 2014-06-12 03:20 ah, that's all the relay 2014-06-12 03:20 weird symbol without the connection 2014-06-12 03:21 which one are you testing ? K1 or K2 ? 2014-06-12 03:21 K1 2014-06-12 03:25 so I shorted base to emitter 2014-06-12 03:25 it still eats 7mA 2014-06-12 03:29 xiangfu has quit [Ping timeout: 264 seconds] 2014-06-12 03:30 xiangfu has joined #qi-hardware 2014-06-12 03:30 desoldered the transistor. 0mA 2014-06-12 03:32 soldered the transistor and literally left the base floating in air. 12mA 2014-06-12 03:43 insanity. there's thousands of variants of this circuit on the web 2014-06-12 03:53 i strongly suspect your transistor is somehow connected the wrong way 2014-06-12 03:53 behaviour would still seem odd, though 2014-06-12 03:54 which transistor is it again you said ? 2014-06-12 03:54 bc547c. marked as "C547C" 2014-06-12 03:54 btw, you can actually connect the npn transistor in reverse (i.e. swap C/E) and it would still kinda work, although with lower hFE 2014-06-12 03:55 let me try to reproduce this on the breadboard... 2014-06-12 03:55 (reverse) yes 2014-06-12 04:22 ... 2014-06-12 04:22 well 2014-06-12 04:23 if I indeed connect it in reverse, then it has an idle current of 12mA 2014-06-12 04:23 which matches what I observe on that board.. 2014-06-12 04:24 now, how did this even happen? the transistor has legs bent that they have a "triangle" footprint. the board, same. 2014-06-12 04:25 what the FUCK 2014-06-12 04:26 Eagle has the footprint in revers 2014-06-12 04:36 sure enough, now it works 2014-06-12 04:40 never trust a footprint you didn't design yourself ;-) 2014-06-12 04:41 and especially not the ones I designed myself 2014-06-12 04:41 since I have attention span of a squirrel on meth 2014-06-12 04:42 i trust the ones i designed because i know that they may be wrong and i have to test them. so they're all properly tested :) 2014-06-12 04:42 besides, with fped it's pretty easy to review the critters 2014-06-12 04:43 it's not exactly complex with eagle, it just never occured to me that BC547 can come in two mirrored footprints, both asymmetrical in a way that would prevent you from misplacing them 2014-06-12 04:43 this is just so fucked up 2014-06-12 04:43 oh also 2014-06-12 04:43 flyback diode not required :P 2014-06-12 04:43 e.g., numbering and precise geometry: http://downloads.qi-hardware.com/people/werner/tmp/kicad-libs-modules.pdf 2014-06-12 04:43 at least the transistor survived more than 50 cycles 2014-06-12 04:43 (that's also roughly what you see on the screen with fped.) 2014-06-12 04:44 i had my transistor experience with gEDA. in kicad i actually found that the stock libs matched each other and reality fairly well 2014-06-12 04:45 but you sometimes got odd shapes 2014-06-12 04:45 not necessarily incorrect but still odd. e.g., standard package X, but from a part with weird thermal requirements, so the footprint for all X is like that 2014-06-12 05:19 BerryHalsak has joined #qi-hardware 2014-06-12 05:41 jekhor has joined #qi-hardware 2014-06-12 06:35 wolfspraul has joined #qi-hardware 2014-06-12 07:09 sb0 has joined #qi-hardware 2014-06-12 07:34 BerryHalsak has quit [Remote host closed the connection] 2014-06-12 07:37 crap. I completely forgot 2014-06-12 07:38 the control board has the *signal* pin hardwired to +5V, and it pulls the *ground* pin down 2014-06-12 07:38 which is kind of really weird but oh well 2014-06-12 07:38 so I basically have a logic OR between "spindle CCW" and "coolant pump on" 2014-06-12 07:39 ... 2014-06-12 07:40 pcercuei has joined #qi-hardware 2014-06-12 07:41 seems like a rev.B is in order 2014-06-12 07:43 bartbes has quit [Quit: No Ping reply in 180 seconds.] 2014-06-12 07:43 bartbes has joined #qi-hardware 2014-06-12 07:53 jekhor has quit [Ping timeout: 264 seconds] 2014-06-12 09:09 rz2k has joined #qi-hardware 2014-06-12 09:36 xiangfu has quit [Ping timeout: 244 seconds] 2014-06-12 09:38 xiangfu has joined #qi-hardware 2014-06-12 10:06 xiangfu has quit [Remote host closed the connection] 2014-06-12 10:47 lamrz has joined #qi-hardware 2014-06-12 10:56 rz2k has quit [Read error: Connection reset by peer] 2014-06-12 11:30 tumdedum has quit [Ping timeout: 240 seconds] 2014-06-12 11:31 tumdedum has joined #qi-hardware 2014-06-12 11:35 rz2k has joined #qi-hardware 2014-06-12 11:54 lamrz has quit [Ping timeout: 252 seconds] 2014-06-12 12:01 lamrz has joined #qi-hardware 2014-06-12 12:30 lamrz has quit [Quit: Leaving] 2014-06-12 12:50 xiangfu has joined #qi-hardware 2014-06-12 13:00 kilae has joined #qi-hardware 2014-06-12 13:12 xiangfu has quit [Remote host closed the connection] 2014-06-12 13:25 jekhor has joined #qi-hardware 2014-06-12 13:56 jekhor has quit [Ping timeout: 244 seconds] 2014-06-12 13:59 pcercuei has quit [Ping timeout: 240 seconds] 2014-06-12 14:06 pcercuei has joined #qi-hardware 2014-06-12 14:36 whitequark: btw, when you draw footprints with eagle, can you output your work in a way that allows for easy review ? e.g., with measurements, like on pages 4 etc. of http://downloads.qi-hardware.com/people/werner/tmp/kicad-libs-modules.pdf ? 2014-06-12 14:37 not as far as I know 2014-06-12 14:38 buuut it would be trivial to write an ULP that outputs that. maybe someone even did it 2014-06-12 14:47 jekhor has joined #qi-hardware 2014-06-12 14:48 wpwrak: why the question? neo900? 2014-06-12 14:53 well.. you really now if all footprints are ok if you soldered the first prototype and it does work without reworks ;) 2014-06-12 14:53 in the end.. one would even need to check reality to documentation since the latter may be wrong from time to time 2014-06-12 15:17 whitequark: yup. collecting arguments against the lame bird, just in case there's an opportunity :) 2014-06-12 15:18 roh: and yes, that's the ultimate test :) actually, not even then you're sure since you may have footprints that happen to work but aren't really good and will give you yield headaches. or the fab silently fixed some problem for you but the next fab won't be so nice ... 2014-06-12 15:18 roh: but with all the measurements you can at least make sure you draw what's in the data sheet. big step forward :) 2014-06-12 15:22 jekhor has quit [Ping timeout: 240 seconds] 2014-06-12 15:29 also, you can see all the measurements at once. not having to hunt them down interactively with some measurement tool 2014-06-12 15:42 lamrz has joined #qi-hardware 2014-06-12 15:45 lamrz_ has joined #qi-hardware 2014-06-12 15:46 lamrz_ has quit [Read error: Connection reset by peer] 2014-06-12 15:46 lamrz has quit [Read error: Connection reset by peer] 2014-06-12 15:46 lamrz_ has joined #qi-hardware 2014-06-12 16:04 lamrz_ has quit [Read error: Connection reset by peer] 2014-06-12 16:09 lamrz has joined #qi-hardware 2014-06-12 16:13 lamrz_ has joined #qi-hardware 2014-06-12 16:16 lamrz has quit [Ping timeout: 244 seconds] 2014-06-12 16:17 pcercuei has quit [Ping timeout: 240 seconds] 2014-06-12 16:22 lamrz__ has joined #qi-hardware 2014-06-12 16:25 lamrz_ has quit [Ping timeout: 252 seconds] 2014-06-12 17:07 ttataa .... big thunderstorm coming. if that sort of weather moves north, they'll need snorkels at the world cup 2014-06-12 17:33 :/ 2014-06-12 17:36 lamrz__ has quit [Ping timeout: 264 seconds] 2014-06-12 17:37 lamrz__ has joined #qi-hardware 2014-06-12 17:52 eintopf has quit [Ping timeout: 240 seconds] 2014-06-12 17:52 eintopf has joined #qi-hardware 2014-06-12 17:56 larsc: about the RF chip I am working on, my company just published some stuff: http://www.m2mnow.biz/2014/06/12/21403-sequans-introduces-colibri-lte-platform-internet-things/ 2014-06-12 17:56 the rf is 3241 2014-06-12 17:56 there are some approx spec 2014-06-12 18:01 ah yes, the latest buzz, the internet of things 2014-06-12 18:04 yes that's just buzzword you don't care about :p 2014-06-12 18:04 that's a chip, you just do whatever you want with it :p 2014-06-12 18:04 I suspect those words are only there for search engines 2014-06-12 18:05 everybody goes crazy about the internet of things recently 2014-06-12 18:06 I guess some market research institute said that this is going to be the next big thing 2014-06-12 18:06 sb0 has quit [Ping timeout: 264 seconds] 2014-06-12 18:06 it could be honestly, if you have a good idea for a cool thing to connect to internet 2014-06-12 18:06 so far I've seen none 2014-06-12 18:07 so far most "small devices" use bluetooth or BLE and don't access internet directly 2014-06-12 18:07 and have small battery life 2014-06-12 18:07 in an occult ritual around 1952, five satanists brought the Thing into the pentagram. the Thing snarls and hisses. the arch-satanist, with a loud voice, proclaims, "Things, I name thee NSA !". thus, what traitor Emmanuel Gol... errr, Snowden, revealed, is merely The Thing claiming was what always has been his by rights. 2014-06-12 18:08 * ysionneau gives a shot of tranquilizer to wpwrak 2014-06-12 18:08 there there :p 2014-06-12 18:08 ;-))) 2014-06-12 18:09 i think the customary procedure would be to sing "warm kitty" :) 2014-06-12 18:18 sb0 has joined #qi-hardware 2014-06-12 18:24 ;) 2014-06-12 18:38 lamrz__ has quit [Quit: Leaving] 2014-06-12 19:02 FDCX has quit [*.net *.split] 2014-06-12 19:05 FDCX has joined #qi-hardware 2014-06-12 19:09 sigh, another chip with embedded APE 2014-06-12 19:09 it sounded so good 2014-06-12 19:09 except for the OTA-management stuff, which I rather wanted to have disabled 2014-06-12 19:11 ok, it got VoLTE, but how's about 3g/2G voice? Which bands will be supported? 2014-06-12 19:13 talking about the Sequans bb+rf chip? 2014-06-12 19:13 yup :-) 2014-06-12 19:13 no 3g/2g at all 2014-06-12 19:13 only 4g 2014-06-12 19:13 oops 2014-06-12 19:13 and only LTE actually 2014-06-12 19:13 that's the downside :) 2014-06-12 19:14 well, there's a reason why it's labeled "for IoT" 2014-06-12 19:14 it's small, cheap, low power chip (don't ask me numbers, I don't have them, but it's our roadmap) 2014-06-12 19:15 actually 3G/UMTS wouldn't even be compatible with the low-power claim 2014-06-12 19:15 and iirc 3G royalties are insane 2014-06-12 19:17 Which bands will be supported? < I don't know the entire list out of my head, I heavily tested band 13 so far 2014-06-12 19:17 I know there has been some tests on band 4 2014-06-12 19:17 don't know about others 2014-06-12 19:17 mainly it will be band A and C/D 2014-06-12 19:18 http://niviuk.free.fr/lte_band.php 2014-06-12 19:18 LTE bands, what a mess 2014-06-12 19:48 sb0 has quit [Quit: Leaving] 2014-06-12 20:18 wej has quit [*.net *.split] 2014-06-12 20:18 wej has joined #qi-hardware 2014-06-12 20:24 jekhor has joined #qi-hardware 2014-06-12 21:24 astr has joined #qi-hardware 2014-06-12 21:27 Recommendations for a tiny/mini/small speaker + amp that is as loud as the one in the nano note or louder? bonus points for even better sound quality :) 2014-06-12 21:29 this is for a diy handheld computer with a 4.3inch lcd to give you a idea of the size of what the speaker is going into 2014-06-12 21:30 rz2k has quit [] 2014-06-12 21:35 jekhor has quit [Ping timeout: 264 seconds] 2014-06-12 21:46 wej has quit [Read error: Connection reset by peer] 2014-06-12 21:50 wej has joined #qi-hardware 2014-06-12 21:58 that's a tricky question 2014-06-12 21:59 generally you won't get away without some sort of resonance chamber or transmission line 2014-06-12 21:59 unless you use speaker of at least ~5cm diameter 2014-06-12 22:00 and even that one will sound mickey mouse when operated without any proper chanber/damping etc 2014-06-12 22:02 general problem: the basic speaker has a front and a backside ;-) sounds trivial bit that's actually the problem you need to fix, since for acoustic waves of wavelength ~radius of speaker and longer, you get a short between front and back 2014-06-12 22:04 so no matter how much energy you blast into your timy speaker and how far the tiny membrane goes forth and back - at 50Hz or 100Hz it just will mix the air and not produce any sound wave 2014-06-12 22:04 the air goes straight around the speaker from front to back 2014-06-12 22:05 you could power a 1cm speaker with 100W and it would only heat up the air 2014-06-12 22:05 at 50Hz 2014-06-12 22:05 you probably wouldn't hear anything in a meter distance 2014-06-12 22:06 so you need a chamber at one of both sides, to contain the air in it and not allow it to just move around the membrane from front to back and vice versa 2014-06-12 22:07 either you use a closed chamber, or an open one which basically is a transmission line then 2014-06-12 22:08 and that chamber must get tuned to the speaker's properties, like inertia and damping of the membrane 2014-06-12 22:09 otherwise you build a organ pipe 2014-06-12 22:09 that only works for one frequecy, but then works extremely good on that single one 2014-06-12 22:12 astr: sometimes you can find so called "closed speakers", they already have a chamber integrated, and on a good seller you can find datasheets that explain how to mount the speaker so it will sound good 2014-06-12 22:15 but often they only mention frequency range, Wattage, resoncance frequency and Q of the speaker transducer, and leave it up to you to calculate a matching chamber for that 2014-06-12 22:15 DocScrutinizer05: thanks, very helpfull 2014-06-12 22:15 sarcasm? 2014-06-12 22:15 sorry! it's as nasty as that 2014-06-12 22:15 bouns points awarded 2014-06-12 22:16 no sorry chinaise way of writing has worn on me. I meant it in a good way 2014-06-12 22:16 :-) 2014-06-12 22:16 too much reading of aliexpress english 2014-06-12 22:18 make sure your chamber is not as perforated and soft material as the white silly thing in GTA01/02 ;-) 2014-06-12 22:21 can you get effenant little speakers that use 1W or less? but still as loud? 2014-06-12 22:22 s/effenant/efficient/g 2014-06-12 22:22 astr meant: "can you get efficient little speakers that use 1W or less? but still as loud?" 2014-06-12 22:22 umm, yup, I think 1W is feasible 2014-06-12 22:22 oh goody good, where? I guess not aliexpress hehe 2014-06-12 22:23 I don't know where to buy small speakers 2014-06-12 22:23 I either used spare parts for an existing design or talked directly to the manufacturer 2014-06-12 22:24 for stuff like GTA03 speakers 2014-06-12 22:24 I haven't found any useful results for closed speakers 2014-06-12 22:24 I'm using ixquick.com 2014-06-12 22:24 ok 2014-06-12 22:24 yeah, they are not exactly common in sub-inch size 2014-06-12 22:25 I mean, such chamber *always* is bulky, that's by physical principles 2014-06-12 22:26 kilae has quit [Quit: ChatZilla 0.9.90.1 [Firefox 29.0.1/20140506152807]] 2014-06-12 22:26 I think I can work with a 5cm one, though I don't know how big the chamber needs to be. I expect my diy handheld to be bulky 2014-06-12 22:27 ooh, 5cm is already a great size 2014-06-12 22:27 bukly any way ... so what harm is a fre more cm for a speaker :P 2014-06-12 22:27 s/fre/few/g 2014-06-12 22:27 astr meant: "bukly any way ... so what harm is a few more cm for a speaker :P" 2014-06-12 22:28 though I would prefer to keep the overall size small so I can still call it a handheld and hold it with one hand 2014-06-12 22:29 it's only for fun alarms, notifications, text2speech 2014-06-12 22:29 the speaker that is 2014-06-12 22:33 then again,I plan to have a pezio sounder = nice and loud for alarms to wake me up hehe mwhahah :D. not sure how to control one on the olimex LIME board 2014-06-12 22:36 typical closed chamber driver/transducer: https://en.wikipedia.org/wiki/Compression_Driver 2014-06-12 22:38 the horn is an acoustical transformer that creates a lot of air moving fast against low force, from a smal amount of air at driver moving slow at very high pressure/force 2014-06-12 22:39 since only a small amount of air needs to get moved by speaker, you can use a small (but rigid strong) membrane 2014-06-12 22:40 in a small case like phone, you don't use horns but chambers or transnissin lines 8usually a combination of both) 2014-06-12 22:40 transmission* 2014-06-12 22:41 http://members.shaw.ca/t-linespeakers/diy-11-apr-99/ http://t-linespeakers.org/projects/chris/index.html 2014-06-12 22:42 http://p10hifi.net/TLS/projects/chris/images/innerView_tn.jpg is pretty good picture - of course yours will have to be smaller, but the principle stays same 2014-06-12 22:44 tiny tiny amp http://www.aliexpress.com/item/Free-Shipping-5pcs-lot-DC-5V-2-Channels-3W-Digital-Power-D-Audio-Amplifier-Board-Amplifier/1758901278.html 2014-06-12 22:47 http://www.quarter-wave.com/ 2014-06-12 22:48 class-D amps there's quite some choice of chips to pick one 2014-06-12 22:49 nice thing about class-D: extremely efficient 2014-06-12 22:49 thus you need no huge heatsinks for lots of Watts to the speaker 2014-06-12 22:51 yep 2014-06-12 22:52 I'm falling asleep, maybe in 12hours I'll resume this chat :) 2014-06-12 22:52 thank you ever so much 2014-06-12 22:54 http://www.quarter-wave.com/TLs/TL_Anatomy.pdf 2014-06-12 22:54 DocScrutinizer05: I'll the my irc running. so feel free to dump and extra info,thoughts questions,links and I'll read them in the morning :) 2014-06-12 22:55 s/and/any/g 2014-06-12 22:55 astr meant: "DocScrutinizer05: I'll the my irc running. so feel free to dump any extra info,thoughts questions,links any I'll read them in the morning :)" 2014-06-12 22:55 nah, i'm also leaving now, cheers! :-9 2014-06-12 22:55 :-) 2014-06-12 22:55 nitnti 2014-06-12 22:56 in http://www.quarter-wave.com you really have it all 2014-06-12 22:56 nice site 2014-06-12 22:57 http://www.quarter-wave.com/Horns/Advanced_Back_Horn.pdf p.3 nice "horn" with coupling chamber design. Transmission line also uses coupling chamber 2014-06-12 23:08 wolfspra1l has joined #qi-hardware 2014-06-12 23:11 wolfspraul has quit [Ping timeout: 240 seconds] 2014-06-12 23:20 http://www.quarter-wave.com/Gallery/Poor_Plumbers_Pluto.jpg :-D 2014-06-12 23:21 nice TL design 2014-06-12 23:57 wpwrak: https://www.indiegogo.com/projects/3dpad-touchless-gesture-controller-arduino-shield-by-ootsidebox