#qi-hardware IRC log for Tuesday, 2014-11-11

whitequarkhaha, so, remember my faulty CNC thing?02:13
whitequarksomeone else also bought it without all the autotransformer fuss, and it blew in almost exactly same way02:13
whitequarkhttp://orionrobots.github.io/CnCNotes/2014/04/13/diagnosing-the-cause.html02:13
whitequarkfet instead of 555 died02:13
whitequarkso it's not me, it's the chinese02:13
DocScrutinizer05sure, what else :)02:20
wpwrakwhitequark: you could start a CNC preemptive repair service :) team up with an importer and reseller, then fix the critters before selling them05:01
whitequarkmmm05:10
whitequarki'm not sure it's worth the hassle05:10
wpwrakyou mean that most of the critters don't fail ? or that people wouldn't pay for a - probably still comparably cheap - device that doesn't go up in flames ?05:22
whitequarki mean it's a lot of work05:23
whitequarklogistics, agreements with suppliers, marketing...05:24
wpwrakmaybe look if there's any large reseller in .eu, then contact them to see if they think that's a problem they'd like to have solved05:28
whitequarkI think there aren't any resellers, they just ship directly from China05:30
whitequarkwhy let someone else take a cut if you can sell it directly on ebay?05:30
whitequarkhm, there are some resellers, it seems05:31
whitequarkholy fuck05:32
whitequarka russian reseller sells it for over 5x the price i bought it at05:32
wpwrakdoes that smell like opportunity ? :)05:36
whitequarkhmm05:38
whitequarkwell, it does05:39
whitequarktoolmaking is a pretty high-margin field in general05:39
wpwraktake cheap but dodgy china stuff, add indestructible russian engineering, own the world :)05:59
whitequarko! http://www.ebay.com/itm/27130498772806:04
whitequarkthey're enormous though, with OD=0.906:05
whitequarkhttp://www.ebay.com/itm/271138757893 these are with OD=0.606:06
whitequarkpretty interesting actually06:06
wpwrakcheaper here: http://www.rembrandtlights.com/shop/re-105006:21
whitequarkit's exactly same company06:22
whitequarkthey even link from ebay footer06:22
wpwrakyup. that's what's funny about it, isn't it ? :)06:22
whitequarkI guess06:22
wpwrakwell, that's the first 6% discount. for the remaining 89% you have to find their chinese fab ;-)06:23
whitequarkhttp://www.aliexpress.com/item/100pcs-PCB-Brass-Rivets-Electronic-Prototype-0-9-mm-x-3-0-mm-Free-shipping/2052610864.html06:24
whitequark100pcs for $4.506:24
wpwrakalas, only a single length. so it's not so nice for 0.8 mm boards06:24
wpwraknow we're talking :)06:24
whitequarkwow, 1000 for $1006:25
whitequarkthese things really aren't expensive to produce, are they06:25
whitequarkit's basically packaging cost06:25
wpwrakand margin :)06:26
whitequarkyou'd need a microscope to see that margin06:26
wpwraknot if you sell at 10 cents per unit :)06:27
whitequarkhehe06:28
wpwrakhmm, aliexpress doesn't seem to have stuff < 0.9 mm, which probably is the shaft diameter06:34
whitequarkyeah, it's ID06:36
wpwrakhmm, or just use nails: http://www.mill-max.com/assets/pdfs/204.pdf06:38
wpwrakof course, mill-max are triple-plus $$$06:39
whitequarkhuuuh06:40
whitequarkdo you solder these, or smash?06:40
wpwraki'd solder them. but feel free to smash ;-)06:41
mooseboobsAnyone know where I could find an example pcb layout for a smartphone (preferably with a MTK chipset) ? 15:49
DocScrutinizer05smashing rivets into PCB is a nasty thing and tends to not yield good results16:20
DocScrutinizer05may sound weird but the FR4/whatever is too brittle and neither elastic nor strong enough16:21
DocScrutinizer05and you generally damage copper plating in 75% of cases16:22
DocScrutinizer05you'll end up with rivets that are loose and don't have contact despite looking perfect16:23
DocScrutinizer05depending on your tools to smash the rivets, you even may deform the PCB so it is a 1.2mm at and around the rivet when it originally been 0.8mm16:24
DocScrutinizer05some methods to smash rivets make the rivet create enormous forces radially to rivet's cylinder16:26
wpwrakso, better to use nails, and no hammer16:59
apeleteHi larsc19:14
apeleteare you there ?19:14
whitequarkDocScrutinizer05: I see22:24
whitequarkrivets did look fishy to me, there should have been a reason almost no one ever uses those22:24
--- Wed Nov 12 201400:00

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