| wolfspraul | wpwrak: thanks again for taking the time to go through the pcb process yesterday! | 00:54 |
|---|---|---|
| wolfspraul | made me happy, I am thinking about buying things now and experimenting :-) | 00:54 |
| wpwrak | was a pleasure :) and you'll have fun, too ;-) | 00:55 |
| wolfspraul | I start easy with some of the smaller utentils, and then I go to an electronics market with xiangfu for some of the more elaborate things, especially also to talk with guys and see what they think and/or use | 00:55 |
| wolfspraul | I will drag xiangfu into this right away as well | 00:55 |
| wpwrak | elaborate things = scope, ultrasonic cleaner, ... ? | 00:55 |
| wpwrak | and let's not forget the CNC :) | 00:55 |
| wolfspraul | yah, basically. also chatting with the guys there | 00:55 |
| wolfspraul | laser printers cost as little as 80 USD now, amazing | 00:57 |
| wpwrak | wow | 00:57 |
| wolfspraul | yeah | 00:57 |
| wolfspraul | I was wondering whether one could directly print onto the pcb? | 00:57 |
| wpwrak | there have been attempts. with ink, though. | 00:58 |
| wolfspraul | how about other printers? | 00:58 |
| wolfspraul | ah ok, but you think the toner transfer is a good standard still, well known to work... | 00:58 |
| wpwrak | there are basically three approaches: | 00:58 |
| wolfspraul | but maybe a laser printer is so flat that it can pull a 0.8mm (or thinner) pcb right through it? :-) | 00:58 |
| wolfspraul | well I can imagine that there are potentially infinite ways how to get this printed | 00:59 |
| wpwrak | 1) lithography, with UV light and photo-coated PCBs. popular but a bit messy. never tried that. that's probably still what industry uses. | 00:59 |
| wpwrak | 2) toner transfer. less capable but reasonably straightforward. | 01:00 |
| wpwrak | 3) milling of the non-copper areas | 01:00 |
| wolfspraul | so you apply the etch resist (positive or negative), then uv light to remove parts, then etch? | 01:00 |
| wolfspraul | yeah I'll just go with the toner transfer first | 01:00 |
| wolfspraul | feels right and uses only cheap tools and simple chemicals and steps | 01:01 |
| wolfspraul | except for your stepper-motor laminator, which I hope to bypass | 01:01 |
| wpwrak | 3) should be cool, because you avoid the chemistry and it's just one step. drawbacks: the finer your traces, the easier your mills break. and you need very precise depth control. i experimented a bit with this but eventually gave up. never succeeded in making a board that actually looked right. | 01:02 |
| wolfspraul | nah I don't feel good about 3 | 01:02 |
| wolfspraul | lithography or lasering, chemicals - that sounds better | 01:03 |
| wpwrak | (photo process) you make a transparent mask, then expose with UV, then develop (chemically), then remove the developed/undeveloped part (not sure if you need special chemicals for that), then etch, then remove all the photoresist (chemically) | 01:04 |
| wpwrak | a heck of a pipeline | 01:04 |
| wolfspraul | maybe you can print the mask with a regular printer just like for those overhead projectors | 01:04 |
| wolfspraul | would need someone who still has a simple lab for analog photo development | 01:05 |
| wpwrak | and it also complicates the handling of the PCB material, since there's the photosensitive coating to worry about | 01:05 |
| wpwrak | you don't need the entire lab. just a few bits of it. | 01:05 |
| wpwrak | but still seems messy to me :) | 01:06 |
| kristianpaul | 80usd !! | 03:13 |
| kristianpaul | wow | 03:13 |
| kristianpaul | toner transfer, indeed is nice, but is not one step solution, so more probably to make mistakes | 03:15 |
| kristianpaul | at least thats my experience | 03:15 |
| kristianpaul | tought laser printing tech had improve a lot, now i should try again :) | 03:15 |
| kristianpaul | 3) is messy, even more mechanical posibillities to get a failure... | 03:17 |
| wolfspraul | you tried toner transfer before? | 03:27 |
| wolfspraul | but it seems you have no idea for a better process? | 03:28 |
| kristianpaul | yes i did when in the University | 03:29 |
| kristianpaul | to be honest i tried no more than 5 times, then decide outsource :) | 03:30 |
| kristianpaul | no idea for better indeed | 03:30 |
| kristianpaul | when i tried laser printed was new.. all was most ink so... | 03:30 |
| kristianpaul | resolution wasnt the best | 03:31 |
| kristianpaul | also i dint knew about the mix of chemicals werner pointed, thats is a cleaner solution | 03:31 |
| wolfspraul | wpwrak: so maybe on my initial purchase, 100ml h2o2 and 100ml hcl is enough? | 05:34 |
| wolfspraul | or more? | 05:35 |
| wpwrak | 100 ml of each should be sufficient for several boards. but you may not be able to buy in such small quantities. especially not the HCl. | 05:50 |
| wpwrak | there, they typical minimum quantity would be more like 0.5-1 l | 05:50 |
| wpwrak | 1 l in easy.com.ar :) peroxide i can get in bottles of 0.1 l - 0.5 l at a pharmacy | 06:07 |
| wpwrak | and don't be shocked by the prices. all that stuff is cheap. | 06:11 |
| wolfspraul | hah yes, went as expected. I got hcl and h202, but at unknown concentrations :-) | 07:35 |
| wolfspraul | when pressed, they would try to come up with the number they thought you would like to hear | 07:35 |
| wolfspraul | labeling of the bottles is chaotic, multiple labels, hand-written, refilled etc. etc. fun. | 07:36 |
| wolfspraul | I was upgraded from "wild blob of duct tape" to a proper rubber knob closure of the bottles only after complaining :-) | 07:37 |
| wolfspraul | so who knows, I will find out the concentration "in the field", china style | 07:37 |
| wolfspraul | the hcl is of some greenish color, and the seller told me I shouldn't spill it over my hands. that's a good sign, must be the right stuff... | 07:38 |
| wolfspraul | maybe there is a standardized and easy test which would let me guess the concentration of the hcl and h2o2? I think I will just try etching instead, see whether anything happens. | 07:40 |
| pabs3 | green hcl? /me guesses it is contaminated, maybe with copper | 09:41 |
| whitequark | wolfspra1l: that's some really bad customer service | 09:55 |
| whitequark | when I bought chemicals on a market here in Moscow, behind the counter there were two nice girls _and_ they knew more about pcbs than I do now | 09:56 |
| whitequark | not to say that bottles etc. were of uncomparable quality. strange. I thought it should be good in China as it's an industrial center and whatnot, no? | 09:56 |
| whitequark | pabs3: or complex ions of Fe, they're green in some cases too | 09:58 |
| whitequark | copper is mostly blue as I've seen it... | 09:59 |
| mth | outdoor bronze turns green, isn't that oxidized copper? | 10:03 |
| mth | wikipedia says it's a carbonate instead: http://en.wikipedia.org/wiki/Patina#Acquired_patina | 10:04 |
| mth | and other non-oxide molecules | 10:05 |
| whitequark | yeah, Copper(I) oxide is red: https://en.wikipedia.org/wiki/Copper(I)_oxide | 10:07 |
| whitequark | and Copper(II) oxide is, erm | 10:08 |
| whitequark | https://en.wikipedia.org/wiki/Copper(II)_oxide | 10:08 |
| whitequark | it's kinda bluish | 10:08 |
| whitequark | as you can see, sulphate is blue: https://en.wikipedia.org/wiki/Copper_sulphate | 10:08 |
| whitequark | so will be any other dissolved compound when copper ions are only coordinated by water molecules | 10:09 |
| LunaVorax | Hello everyone! | 10:30 |
| kristianpaul | hi | 11:05 |
| qi-bot | [commit] Adam Wang: js28f256j3f105.lib: pin 43, pin name changed to VCCQ (master) http://qi-hw.com/p/kicad-libs/bbab963 | 11:51 |
| qi-bot | [commit] Adam Wang: Merge branch 'master' of projects.qi-hardware.com:kicad-libs (master) http://qi-hw.com/p/kicad-libs/4be16e3 | 11:51 |
| wpwrak | wolfspraul: green is a bit unusual. should be more like colorless or perhaps a little yellowish. but maybe it's an additive. that sometimes happens. is it still transparent enough to see through a cm of it ? | 12:07 |
| wolfspraul | yes definitely | 12:08 |
| wolfspraul | concentration no idea | 12:08 |
| wolfspraul | and for the h2o2 I'm not even sure whether it is h2o2 :-) | 12:08 |
| wolfspraul | the pharmacy had a more trustworthy h2o2, but concentration was listed at 2.5%-3.5% only | 12:09 |
| wpwrak | you can try this: cut a bit off a PCB. make you mixture. WEAR GLOVES AND GOGGLES. set up the stuff outside, somewhere where spills don't harm. even if it would decide to boil. | 12:09 |
| wolfspraul | is there an easy way to reduce h2o2 to increase the concentration? | 12:09 |
| wpwrak | weark clothes you don't mind discarding. if you have some plastic poncho, raincoat, or such, wear that too. | 12:09 |
| wpwrak | then toss the copper inside and see what happens. | 12:10 |
| wpwrak | (reduce concentration) yes, add water :) | 12:10 |
| wolfspraul | need to increase the concentration | 12:11 |
| wpwrak | oh, increase | 12:11 |
| wpwrak | naw, not really | 12:11 |
| wolfspraul | the h2o2 at the pharmacy is only 2.5%-3.5% | 12:11 |
| wpwrak | that's probably good enough. lemme check what the one i have is ... | 12:11 |
| wolfspraul | yes I will just try, the main protection being that I will try with small amounts | 12:13 |
| wolfspraul | come on everybody here uses this stuff all over, I won't make myself too laughable :-) | 12:14 |
| wpwrak | hmm. bottle says "10 volumenes". 10 % ? let's find out what the google scienctists has to say about it ... | 12:14 |
| wpwrak | with the peroxide concentration known to be low, you're already on much safer ground. when you wrote that it's all weird, i thought, the peroxide was unknown too | 12:15 |
| wolfspraul | it is, I got the one in the market, not the pharmacy | 12:15 |
| wolfspraul | could be anything :-) | 12:15 |
| wolfspraul | I will get the one from the pharmacy too, good idea | 12:15 |
| wpwrak | (if you mix, say, 35% HCl with 30% H2Os, you get a VERY reaction-happy acid. etches a board clean in just a few seconds. alas, it also starts boiling quickly ...) | 12:16 |
| wpwrak | s/H2Os/H2O2 | 12:16 |
| Action: wpwrak is still in pre-caffeine state | 12:16 | |
| wolfspraul | sure but most likely the stuff I buy here errs on the side of water | 12:16 |
| wolfspraul | not on the other side | 12:16 |
| wolfspraul | I will try a little :-) | 12:16 |
| wolfspraul | there's no way I can get high-reliability chemicals anyway here | 12:17 |
| wpwrak | good :) so the chinese are not all _that_ keen on massively negative population growth ;-) | 12:17 |
| wpwrak | since we don't know for sure what the acid is, you should follow the usual precautions: give peroxide into the basin first, then add the acid. that way, the risk of splashes with high concentration is lower | 12:18 |
| wolfspraul | good | 12:19 |
| wpwrak | you should still wear gloves and glasses/goggles, though | 12:19 |
| wpwrak | (peroxide) "10 volumenes" = 3%. so yours is perfect. | 12:20 |
| wolfspraul | ah ok | 12:20 |
| wpwrak | so only the HCl is unknown. during etching, a bit of Cl gas should escape. it has a very characteristic smell. so that shuold allow you to tell tht there's indeed Cl in there | 12:22 |
| wpwrak | so, first experiment: make a bit of acid and toss a piece of copper-clad PCB inside. 1 cm^2 will do nicely | 12:22 |
| wpwrak | then watch what happens. move it around a bit with a stick made of plastic, wood, or glass | 12:23 |
| wolfspraul | sure, I remember from my visit :-) | 12:23 |
| wpwrak | if it's double-sided, you can also turn it over, move it for a while "bottom up", then flip, etc. | 12:23 |
| wpwrak | you should see that both sides etch at different speeds. that's probably because of differences in the flow of the acid in the basin. i find that usually the bottom side etches faster. | 12:24 |
| wpwrak | the chemical reaction should produce 1) little gas bubbles on the copper. 2) bluish/greenish traces that come off the board. the blue are your copper ions. the green is them with chloride. | 12:27 |
| wpwrak | pity that your HCl already has that color. but you may still see some changes. eventually, the whole solution turns green-blueish, even if you start with "clean" HCl. | 12:28 |
| wpwrak | complete removal of all the copper should take between 10-20 minutes. | 12:29 |
| wpwrak | ah, maybe give your pcb a scrub with steel wool first. not sure how much the acid likes the copper oxide. might slow it down. | 12:30 |
| wpwrak | (steel wool and then clean with alcohol. wouldn't want to add iron to the reaction.) | 12:33 |
| wolfspraul | good good | 12:35 |
| qi-bot | [commit] Maarten ter Huurne: MIPS: JZ4740: SLCD: Fixed sysfs tvout value parsing. (jz-3.3) http://qi-hw.com/p/qi-kernel/f20d896 | 13:28 |
| qi-bot | [commit] Maarten ter Huurne: MIPS: JZ4740: SLCD: Ignore sysfs rewrite of current TV-out mode (jz-3.3) http://qi-hw.com/p/qi-kernel/0a96d72 | 13:28 |
| canoso | have anyone used gnublin embedded GNU/Linux? | 21:31 |
| GNUtoo-desktop | canoso, what's that? | 21:34 |
| canoso | it is a embedded linux board with an ARM microcontroller. | 21:35 |
| canoso | It is open hardware | 21:35 |
| canoso | http://www.gnublin.org | 21:35 |
| GNUtoo-desktop | is it 100% free software? | 21:45 |
| GNUtoo-desktop | seem so at first sight | 21:46 |
| GNUtoo-desktop | btw how much does it cost? | 21:46 |
| canoso | about 50 euros | 21:46 |
| GNUtoo-desktop | ok | 21:47 |
| lindi- | wrong language :( | 21:47 |
| GNUtoo-desktop | ? | 21:47 |
| lindi- | (german) | 21:47 |
| GNUtoo-desktop | ah ok | 21:47 |
| canoso | it has USB On the Go. Can I connect any usb device to it? | 21:48 |
| lindi- | canoso: I wouldn't call that a microcontroller | 21:48 |
| lindi- | since linux doesn't run on microcontrollers :) | 21:49 |
| GNUtoo-desktop | depends | 21:49 |
| GNUtoo-desktop | linux runs on blackfin for instance | 21:49 |
| GNUtoo-desktop | or stuff without mmu | 21:49 |
| GNUtoo-desktop | but in that case it's a SOC | 21:49 |
| lindi- | and it has 8 MB of RAM | 21:50 |
| GNUtoo-desktop | yes | 21:50 |
| GNUtoo-desktop | I think the minimum specs is 4M | 21:50 |
| canoso | lindi-: http://www.nxp.com/products/microcontrollers/arm9/lpc3100/#overview | 21:50 |
| canoso | lindi-: it is a microcontroller | 21:50 |
| canoso | lindi-: it has many peripherals integrated in the same chip | 21:50 |
| canoso | lindi-: and RAM in the chip | 21:50 |
| lindi- | openmoko has ram in the chip too | 21:51 |
| lindi- | (half of it) | 21:51 |
| lindi- | canoso: I guess we just have different terminology :) | 21:51 |
| GNUtoo-desktop | microcontroller and SOC are not that different | 21:51 |
| lindi- | for me microcontroller is something without MMU certainly and without cache too | 21:51 |
| GNUtoo-desktop | linux run on some stuff without MMU | 21:52 |
| lindi- | yeah but that's quite an exception | 21:52 |
| kristianpaul | milkymist soc dont have mmu btw :-) | 21:52 |
| GNUtoo-desktop | lindi-, an exception that is in mainline? | 21:52 |
| lindi- | GNUtoo-desktop: yeah :) | 21:54 |
| wolfspraul | canoso: [gnublin] nice link, thanks a lot! | 23:41 |
| wolfspraul | first time I see this, and please always feel free to post links to new or potentially new open hardware anything here | 23:41 |
| wolfspraul | we love to learn | 23:41 |
| wolfspraul | :-) | 23:41 |
| wolfspraul | I haven't checked about license, tools, etc. but anyway, nice simple project. | 23:42 |
| GNUtoo-desktop | yes indeed seem nice | 23:46 |
| wpwrak | lindi-: linux runs fine on microcontrollers. here's an example: http://www.bit-tech.net/news/hardware/2012/03/30/linux-atmel-microcontrollers/1 | 23:46 |
| canoso | wolfspraul: ty | 23:48 |
| --- Thu May 17 2012 | 00:00 | |
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