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| 03:10.03 | arossdotme-planb | when ya look at this, how good or bad do you think it is? i think some people on diyaudio.com forum said it was good :/. it does have the sleep and mute pins exposed via connector which is the attractive feature :) http://www.aliexpress.com/item/TPA3116-digital-class-D-amplifier-50W-50W-with-silent-sleep-design-with-heat-sink/32654679975.html?ws_ab_test=searchweb201556_0,searchweb201602_2_10037_10017_507_10032_401_10040,searchw |
| 03:10.03 | arossdotme-planb | eb201603_3&btsid=c43559b8-b84a-4ded-b95c-a11eb830efa1 |
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| 18:15.54 | wpwrak | heroic rework of he day: unsoldered a worn-out micro USB connector (from anelok) and replaced it. amazingly, the board still works. but my disdain for micro USB only deepens ... |
| 18:22.33 | DocScrutinizer05 | well, prolly for anything micro-* |
| 18:23.15 | DocScrutinizer05 | that's the problem with all micro things: they are really small |
| 18:25.23 | EDT | wpwrak: you can't hear it, but I'm clapping for you |
| 19:32.23 | *** join/#qi-hardware wej (~j@2a03:1b20:3:f011::f1e) |
| 19:40.18 | wpwrak | EDT: thanks ! ;-) the trick was to let "chip-quik" do its magic. tossed a huge drop on the connector (on the shield), heated it at 400something C for a minute or so, until it felt unwelcome and slid off the board. |
| 19:42.10 | wpwrak | DocScrutinizer05: naw, it's the specific suckiness of USB micro. they somehow messed up the angular tolerances, by trying to make them a bit too short. mini was fine and USB C also seems to correct this problem. |
| 19:42.24 | wpwrak | there's probably just 0.5 mm or so missing, but that's enough ... |
| 19:55.32 | whitequark | wpwrak: chipquik si fucking awesome |
| 19:55.51 | whitequark | I've reworked complete boards with chipquik two times or even more, with no lifted traces |
| 20:09.31 | DocScrutinizer05 | which product of chipquik? |
| 20:10.25 | DocScrutinizer05 | there is quite a number of different chipquik products http://www.chipquik.com/store/ |
| 20:13.12 | DocScrutinizer05 | ooh I see, alloy with a melting point <100°C |
| 20:14.51 | DocScrutinizer05 | wood's metal |
| 20:15.25 | DocScrutinizer05 | rather Roses metal I hope |
| 20:17.52 | DocScrutinizer05 | https://de.wikipedia.org/wiki/Roses_Metall |
| 20:25.00 | EDT | So I just flashed my nanonote to the most recent version, and it doesn't have emacs installed or available in the repos |
| 20:25.10 | EDT | anyone have experience with emacs and the nanonote? |
| 20:26.22 | whitequark | no |
| 20:26.30 | whitequark | DocScrutinizer05: its an indium alloy |
| 20:26.40 | DocScrutinizer05 | indium? wow |
| 20:26.43 | whitequark | Pb-free |
| 20:26.58 | whitequark | I think it's BiInSn but exact composition is a trade secret |
| 20:28.37 | whitequark | indium is not that expensive anyway |
| 20:28.44 | whitequark | I have a kilo of InSn |
| 20:33.02 | DocScrutinizer05 | Tin, Silver, Bismut, Antimony, Indium, Copper |
| 20:33.14 | DocScrutinizer05 | http://www.chipquik.com/msds/SMD4.5NL.pdf |
| 20:40.31 | DocScrutinizer05 | hmmmm :-) Solder Paste no clean Sn42/Bi57.6/Ag0.4 Low Temp 138C |
| 20:41.09 | DocScrutinizer05 | though.... will prolly fall off the PCB before chip reaches max operating temperature ;-P |
| 20:52.16 | DocScrutinizer05 | sth completely off topic: I recently learned cochlear implants have 12 to 28 electrodes, also because they can't get more wires into the whole thing without it getting too rigid. How about one-wire serial setup with active component for each electrode? |
| 20:53.42 | DocScrutinizer05 | they also said that more electrodes would be useless since crosstalk gets too large, but I guess that could get fixed by carefully modelling a matrix that creates compensation current on neighbor electrodes |
| 20:54.55 | whitequark | haahha cochlear implants |
| 20:55.03 | DocScrutinizer05 | haha? |
| 20:55.12 | whitequark | fun fact: for all the techie talk about 'uploading' we still have no idea how hearing works |
| 20:55.39 | DocScrutinizer05 | sounds about right |
| 20:56.07 | whitequark | i'm sometimes chatting with a friendly neuroscientist who does a masters in that area |
| 20:57.06 | DocScrutinizer05 | they recently implemented MP3-alike audiophysiological data reduction to the cochlear implant data, improving legibility of the created sensation drastically |
| 20:57.30 | whitequark | *nod* |
| 21:00.28 | DocScrutinizer05 | (crosstalk) even when we limit the count of concurrently active electrodes to maybe 24, I guess it still would make a huge difference when you could choose the position of those active electrodes from a say 500 existing electrodes |
| 21:02.17 | DocScrutinizer05 | a simple one-wire daisychain design (actually maybe 3 or 4 wires then) should facilitate a way higher number of electrodes |
| 21:02.34 | whitequark | lemme ask him |
| 21:02.35 | DocScrutinizer05 | higher than 28 |
| 21:03.14 | DocScrutinizer05 | the needed node chips are prolly as small as 0.2*0.2*0.05mm or somesuch |
| 21:04.23 | DocScrutinizer05 | they basicaly could integrate the electrode already |
| 21:05.12 | DocScrutinizer05 | should file a patent ;-P |
| 21:05.36 | DocScrutinizer05 | but like always, I bet somebody else already did |
| 21:09.35 | DocScrutinizer05 | I already think I know the electrical macro design: GND wire, V+, V- as bus. Data as daisychain from electrode to electrode, where the electrodes actually are chips |
| 21:12.54 | DocScrutinizer05 | maybe even 'in plane switching' with two adjacent electrodes (integrated into one chip) could work to reduce crosstalk |
| 21:15.01 | DocScrutinizer05 | whitequark: (ask him) yes, please do. Let me know what he thinks |
| 21:15.43 | DocScrutinizer05 | maybe we could even start a project |
| 21:29.59 | whitequark | lol nope, have you seen the approval time for medtech? |
| 21:30.24 | whitequark | how does that count against your life expectancy? how does that count against *my* life expectancy? |
| 21:37.39 | DocScrutinizer05 | yeah |
| 21:37.52 | DocScrutinizer05 | however an intriguing topic |
| 21:38.29 | DocScrutinizer05 | reads about Anisotrope Conductive Adhesive, used in flipchip mounting |
| 21:39.38 | DocScrutinizer05 | (approval time) the idea for sure wouldn't be to start a medical supply company. Rather to sell the concept to such company |
| 21:41.36 | whitequark | that doesn't really happen because concepts are worthless |
| 21:41.47 | DocScrutinizer05 | prolly |
| 21:41.52 | whitequark | ask a grad student who really doesn't want to study |
| 21:42.46 | DocScrutinizer05 | I might try to contact the university scientists that do R&D on that stuff |
| 21:43.50 | whitequark | " Error: Multiple definition of the extension constructor name Data_source_error. |
| 21:43.53 | whitequark | er |
| 21:43.56 | whitequark | wrong paste |
| 21:44.08 | DocScrutinizer05 | btw the topic is somewhat similar to the also really pathetic retina implants they test nowadays |
| 21:45.04 | DocScrutinizer05 | which have a resolution of 8*8 or somesuch |
| 21:46.11 | DocScrutinizer05 | for the latter they are evidently still in prototype state, with different issues than resolution |
| 21:46.35 | DocScrutinizer05 | cochlear implants are well established |
| 21:47.58 | whitequark | "afaiu the major restriction on electrode counts is actually crosstalk between electrodes - plus more electrodes at the same stim current means more charge transfer which is bad for both the electrodes and the body. Plus these active devices would have to operate inside the cochlea if I understand the intended design - complicates. Pictures: http://www.medel.com/blog/close-up-with-cochlear-implant-electrode-arrays/" |
| 21:48.49 | DocScrutinizer05 | yes, that sounds all right but not to the point |
| 21:52.15 | DocScrutinizer05 | in that picture imagine those 12 electrodes with their separating spaces in between would each be broken up into - say- 20 segments of 'partial' electrodes of which an arbitrary consecutive sequence of 10 would get activated as one 'macro' electrode, acting exactly on same physical parameters like the recent discrete design, just the virtual position of such virtual electrode could get shifted in 10 steps back and forth |
| 21:53.44 | DocScrutinizer05 | then there's also the idea of "in plane switching" where the electrode potential isn't vs "GND" but vs twin electrode 't |
| 21:54.43 | DocScrutinizer05 | >>active devices would have to operate inside the cochlea<< is an issue which gets solved on a technical level, unrelated to medical concerns |
| 21:57.40 | DocScrutinizer05 | I think flipchip will just work fine when embedded into that transparent silicon |
| 21:57.43 | whitequark | the majority of issues with implants are technical though... |
| 21:57.53 | DocScrutinizer05 | sure, I know |
| 21:58.11 | DocScrutinizer05 | it's an endless nightmare of "damn this electrode material corrodes" etc |
| 21:58.56 | DocScrutinizer05 | but those issues are not really entangled with the core idea of daisychaining and having more and smaller electrodes |
| 22:00.20 | DocScrutinizer05 | IPS could help a lot with crosstalk, and I'd bet nobody considered that so far since it wouldn't help anyway as long as you need to double the number of electrodes for it and you can't get more than 28 of them because of technical reasons |
| 22:02.45 | DocScrutinizer05 | I know the stimulus current must not exceed rather low levels or there will be long term damage to the nerves |
| 22:03.34 | DocScrutinizer05 | but that's a concern that gets handled on a calibration level, not at design level |
| 22:03.56 | DocScrutinizer05 | s/ on / at / |
| 22:03.57 | qi-bot | DocScrutinizer05 meant: "but that's a concern that gets handled at a calibration level, not at design level" |
| 22:04.39 | DocScrutinizer05 | IOW more electrodes doesn't per se mean higher stimulus current |
| 22:06.26 | DocScrutinizer05 | au contraire IPS might mean you get away with way lower stimulus current |
| 22:07.02 | DocScrutinizer05 | and crosstalk outside of the area of the twin electrodes should be drastically reduced |
| 22:14.28 | DocScrutinizer05 | umm this http://i2.wp.com/www.medel.com/blog/wp-content/uploads/2013/10/Hüttenbrink-011.jpg?w=1140 already looks like they do IPS |
| 22:14.32 | DocScrutinizer05 | no? |
| 22:16.46 | DocScrutinizer05 | yes, the video clearly shows pairs of electrodes |
| 22:17.34 | DocScrutinizer05 | ok, didn't know they already use IPS |
| 22:20.35 | DocScrutinizer05 | http://i1.wp.com/www.medel.com/blog/wp-content/uploads/2014/01/Top-of-electrode.jpg?resize=600%2C450 however doesn't suggest they actually use 24 wires for that 12 electrode pairs |
| 22:43.43 | DocScrutinizer05 | whitequark: could you ask your contact what's the deal with thiose 24 electrodes in pairs of 2, vs seemingly only 12 wires at the end where the processor connects? |
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