#qi-hardware IRC log for Sunday, 2013-08-04

hellekinwpwrak: I'm cooking soup in the hacklab, there's pizz00:04
wpwrakat the heretics ?00:05
rohmeeeh.00:08
hellekinheretics? 00:10
rohwho was the evil dude who put a 10pin ic into a package which is only 1.8x1.4mm and 0.5mm thick?00:10
wpwrakheredia00:10
rohRSW (R-PUQFN-N10)00:11
hellekinin Barracas. I'm going to get some beer. Cris is on her way. 00:11
wpwrakah, better located hacklab :)00:11
hellekinwpwrak: aristobulo del valle 185100:11
rohstay clear. dont solder by hand. and if you do: heat up some solid flux and dunk the tinned part before placing00:11
rohcolophonium in my case.00:13
wpwrakhellekin: can't go today. but tell me a bit in advance the next time00:13
wpwrakroh: (size) nice and compact :)00:14
hellekinwpwrak: normally every Saturday, but I didn't expect to stay that late nor to cook :]00:14
hellekinbut the organic garden gave some food so00:14
hellekinok, time to get beeeeeer :]00:14
wpwrakheh :)00:25
wpwrakhmm, github is stuttering00:38
DocScrutinizer05indeed01:20
DocScrutinizer05btw wpwrak, you might find the PCB[-RF/aerial] design (as well as the chip) in http://www.nordicsemi.com/kor/content/download/2726/34069/file/nRF24L01P_Product_Specification_1_0.pdf inspiring01:21
wpwrakkeeping the antenna simple :)01:28
wpwrakthe chip doesn't look so sexy, though. GFSK.01:28
DocScrutinizer05what's wrong with GFSK (or any modulation as long as RX and TX understand it)?01:33
wpwrakyes, finding a suitable peer01:34
wpwrakyou're deep in non-standard land there01:34
DocScrutinizer05those chips are not meant to be compatible to anything else01:34
wpwrakyeah. that's why i find them somewhat unsexy01:35
DocScrutinizer05and as long as the few uA in standbymode-1 are actually for idle RX with wakeup, I'm all fine with that01:35
DocScrutinizer05I'm rather wondering what's RL range such a pair of transceivers can do01:36
wpwrakthe at86rf231 needs 20 nA in sleep01:37
wpwrak1/45 of the 900 nA bonfire that nordic chip produces ;-)01:38
DocScrutinizer05mhm01:38
DocScrutinizer05sounds good, indeed01:38
wpwrakand it can blast the neighbourhood at a full +3 dBm01:39
DocScrutinizer05and sleep means it's listening?01:39
DocScrutinizer05dang, I'm so out of hw business01:40
wpwrakbtw, there's now a lower-cost variant, the 23201:40
wpwrakno, sleep means it's sleeping :)01:40
DocScrutinizer05meh01:41
wpwraklistening only to the I/O line that tells it whether to sleep or wake01:41
DocScrutinizer05I'm only interested in receivers to actually *receive* and still need only uA or nA01:41
DocScrutinizer05no use in an actor that's only listening 0.01% of thime01:42
DocScrutinizer05time*01:42
DocScrutinizer05I need RF that can operate actors from let's say 3V 1000mAh for months01:43
wpwraklistening equals receiving01:43
wpwrakso, 12.1 mA in your nordic chip01:44
DocScrutinizer05that's awful01:44
wpwrak11.8 mA in the at86rf232. also here, atmel wins :)01:45
DocScrutinizer05I wonder what those FS20 / homematic are using01:45
wpwrakthe at86rf231 burnt 12.3 mA, losing by a narrow margin. guess marketing had to have that fixed :)01:45
DocScrutinizer05I mean, my doorlock works a year from 4 AAA01:46
DocScrutinizer05and it opens instantly when I press the button of the key transmitter01:47
wpwrakmake the transmitter send a continuous burst. wake up every ~50 ms, bring up the receiver (at86rf231: 380+110 us), listen for a few 100 us, go back to sleep01:49
wpwrakthere you are, 2% duty cycle, and it's still "instantaneous"01:50
DocScrutinizer05anyway, need to have a walk to next postpox, sending out some PAR414 "backup battery" 0.06F capacitors to guys who wanna fix their phones' RTC01:50
wpwrakyou even have enough time to miss a few transmissions01:50
wpwrak;-)01:51
wpwrakinterest timing for going postal :)01:51
DocScrutinizer05air is better now01:51
DocScrutinizer05you know, here it's summer01:52
DocScrutinizer05in daytime it's been unbearable01:52
DocScrutinizer05well, actually today 'only' 32°C01:53
DocScrutinizer055° less than the last 2 days01:53
DocScrutinizer05can the RX start up in such short time, to full operation and sensitivity?01:54
DocScrutinizer05well, probably it should, considering the number of full sine waves at e.g. 680MHz01:57
wpwrak32 C *snicker*01:57
DocScrutinizer05even 4 times as many on those chips we discussed01:57
DocScrutinizer05I know, you need gloves and a thick jacket to survive such low temperatures01:58
wpwrak110 us from sleep to xtal up, 380 us from that to receiving, yes01:59
DocScrutinizer05mhm01:59
DocScrutinizer050.5ms01:59
DocScrutinizer05well01:59
DocScrutinizer05fair enough02:00
wpwrakthose chips have other issues, but rf slowness is not one of them02:00
DocScrutinizer05then we're actually at 100some uA02:00
DocScrutinizer05plus overhead for the controller02:01
wpwrakyeah02:02
DocScrutinizer05I'm looking for chips that have such duty cycle powersaving integrated02:02
DocScrutinizer05a simple carrier detect was already fine, of course a MAC addr decoding even better02:03
wpwrakthere's a problem with the MAC protocol. it requires CSMA, so you get a hefty extra delay you can't control. this means that you effectively have to stay on the air a bit longer.02:04
wpwrakbut you can play tricks, e.g., see if there's a carrier, even if you missed the beginning of the frame02:04
wpwrakif you see a carrier, then stay up a bit longer02:04
DocScrutinizer05that's what I meant02:04
wpwrakif you really want to go primitive, only check the RSSI and make the sender emit a constant wave (it can do that in test mode) ;-)02:05
wpwrakof course, all your wlan-loving neighbours will hate you ... ;-)02:06
DocScrutinizer05I hate that idiot spider that always checks path /b/c/d when somewhere it finds an URL /a/b/c/d02:08
DocScrutinizer05spams my server logs each night02:08
DocScrutinizer05    404 Not Found02:08
DocScrutinizer05       /950/myimages/xtract/flasher32/usr/share/doc/copyright: 2 Time(s)02:08
DocScrutinizer05       /950/myimages/xtract/flasher32/usr/share/flasher: 1 Time(s)02:08
DocScrutinizer05actually it checks /a/b/d02:10
DocScrutinizer05must be microsoft02:11
qi-bot[commit] Maarten ter Huurne: The "tr1" namespace is no longer needed now that we're on C++11 (packages) http://qi-hw.com/p/gmenu2x/fb8f4e602:15
qi-bot[commit] Maarten ter Huurne: Do not draw NULL icon (packages) http://qi-hw.com/p/gmenu2x/dd55b7202:15
qi-bot[commit] Maarten ter Huurne: Restrict access to Link::recalcCoordinates() (packages) http://qi-hw.com/p/gmenu2x/a7b316602:15
qi-bot[commit] Maarten ter Huurne: Cleaned up Menu::loadIcons() (packages) http://qi-hw.com/p/gmenu2x/40372d102:15
qi-bot[commit] Maarten ter Huurne: Moved most Menu::loadIcons() code into Link/LinkApp classes (packages) http://qi-hw.com/p/gmenu2x/a9b5d8b02:15
qi-bot[commit] Maarten ter Huurne: Made ASFont::utf8Code() a function in inputdialog.cpp instead (packages) http://qi-hw.com/p/gmenu2x/0046fa902:15
qi-bot[commit] Maarten ter Huurne: Renamed ASFont class to just Font (packages) http://qi-hw.com/p/gmenu2x/724aefe02:15
qi-bot[commit] Maarten ter Huurne: Don't construct non-functional Font objects (packages) http://qi-hw.com/p/gmenu2x/f8dc4c702:15
qi-bot[commit] Maarten ter Huurne: Put main loop painting code in separate methods (packages) http://qi-hw.com/p/gmenu2x/cbe773502:15
DocScrutinizer05wpwrak: at86rf231 is one chip, with RF and MCU, no?02:34
DocScrutinizer05btw r0let's antenna is quite "different": chip antenna plus a pcb triangle pad nearby, as far as I can see it02:37
DocScrutinizer05r0ket's*02:37
DocScrutinizer05http://www.johansontechnology.com/images/stories/ip/rf-antennas/Antenna_2450AT42A100_08-29-2008.pdf  I honestly wonder if that triangle copperpad nearby has seen any considerations regarding RF02:43
DocScrutinizer05http://maemo.cloud-7.de/share-service/20130804_003.jpg02:46
DocScrutinizer05ooh, nevermind, it's just a silly lightgreen silkscreen printing02:52
DocScrutinizer05btw those guys are real hackers :-) they dualuse LED3 (red, upper right, charge-LED, PIO1_11) as ambient light sensor. Feels almost like one of my original designs03:08
DocScrutinizer05http://r0ket.badge.events.ccc.de/hardware  http://r0ket.badge.events.ccc.de/_media/r0ket.sch.png03:09
wpwrakthe 231 has no mcu. there others that integrate an avr. but better get something decent03:09
DocScrutinizer05wpwrak: do you know why green LEDs get a red component and thus shine yellowish when operated at or above upper current limit?03:25
wpwraknaw, never noticed such an effect03:47
whitequarkoh, there indeed is one04:50
uncloudedI always wondered why that was05:35
DocScrutinizer05well, if nothing is published anywhere about that, we have one simple option: find out by ourselves about a few parameters05:39
DocScrutinizer05I lately got a nice electronically controlled reflow hot air tool. Might test if it's temperature05:40
DocScrutinizer05cost me an LED ;-)05:40
DocScrutinizer05what I already know: the effect is accumulative, I.E. it builds up and increases while current stays same05:42
DocScrutinizer05and it's (mostly?) reversible - though LEDs tend to get dimmer, resp they efficiency seems to drop. They deteriorate05:44
DocScrutinizer05I'd suspect some effect that's closely related to the semiconductor crystal deteriorating due to heat05:45
whitequarkinteresting05:47
whitequarkI know  that temperature changes bandgap voltage, which in turn directly affects color05:48
whitequarkit's very visible if you e.g. put the led in liquid nitrogen05:48
whitequarkI'd expect that heating it up would redistribute impurities (?) changing bandgap voltage as well?05:48
whitequarkor no, actually, that prolly has nothing to do with impurities05:52
whitequarkjust the temperature.05:52
whitequarkhttp://ecee.colorado.edu/~bart/book/eband5.htm05:55
roh.s15:53
lunavoraxHello everyone23:33
lunavoraxI've just become aware of the OLinuXino project23:33
lunavoraxAny thoughts about that?23:33
--- Mon Aug 5 201300:00

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