DocScrutinizer05 changed the topic of #qi-hardware to: Copyleft hardware - http://qi-hardware.com | hardware hackers join here to discuss Ben NanoNote, atben / atusb 802.15.4 wireless, and other community driven hw projects | public logging at http://en.qi-hardware.com/irclogs and http://irclog.whitequark.org/qi-hardware
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<whitequark> what the fuck.
<whitequark> silicone didn't work, and I have just learned why
<whitequark> because the water chamber is not actually welded shut, it's snap-on, like the motor chamber
<whitequark> *of course* that shit leaks
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<whitequark> whee, 2nd issue of c't hacks
<whitequark> also I've put a lot of the silicone over the latch of the water chamber and then closed it. it worked, it no longer leaks
<wpwrak> more silicone helps more. it's just a question of quantity until nothing could possibly leak anymore.
<whitequark> alternatively, encase it in a solid block of epoxy
<whitequark> no joke; that's how soviet military electronics was actually processed
<whitequark> they even developed a special kind of epoxy which negligibly shrinks during curing, so that it wouldn't tear components off
<wpwrak> must be hell to change those tubes ...
<wpwrak> or do they still use relays ?
<whitequark> meh
<whitequark> soviet integrated circuits. biggest integrated circuits in the world
<whitequark> usually encased in ceramic & with a shitload of gold on the pins
<whitequark> you could literally sell a few ICs and buy a nice car
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<whitequark> Au, Pt, Pd, Ir, sometimes even more rare stuff
<whitequark> "one IC contains 19,4737mg of Au"
<whitequark> that's in *grams*
<sb0> they indicate the gold content in the datasheet?
<sb0> or is this not a datasheet?
<whitequark> it's a datasheet
<whitequark> a part of it
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<sb0> would be fun to visit the fabs :)
<whitequark> well, you'd have to get a time machine first
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<wpwrak> DocScrutinizer05: you asked about raster's whereabouts. i guess this may explain it: www.heise.de/newsticker/meldung/Samsung-Z-Das-erste-Smartphone-mit-Tizen-statt-Android-ist-fertig-2213903.html
<DocScrutinizer05> eugh
<wpwrak> (in german, "tizen" immediately draws your mind towards "tits". there are two words, "titten" and "zitzen", both meaning that)
<DocScrutinizer05> hehe
<DocScrutinizer05> I always grab my ear when I read "Tizen"
<DocScrutinizer05> also not exactly a lucky association
<wpwrak> ouch !
<sb0> whitequark, I suspect some are still around :)
<whitequark> but I can say for a fact that *no* precious metals have survived for more than like
<whitequark> ten minutes after the fall of ussr
<sb0> I know a fab near Warsaw that still uses a lot of USSR-era equipment
<sb0> including large oil diffusion pumps etc.
<sb0> maybe mercury, even :)
<whitequark> mmm, pumps
<whitequark> mercury isn't really precious
<sb0> (it's been on my todo-list for a while, but I'm never in Poland at the right time)
<sb0> and I don't mean for the precious metals, just for the vacuum/electronic porn
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<whitequark> what's a good way to make a constant-current regulator for 1A?
<whitequark> lm317?
<whitequark> hm, no, that'd dissipate at least 3W
<ysionneau> STCS1A ?
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<whitequark> ysionneau: oh great
<whitequark> ysionneau: oh actually not, I can't find anywhere to buy it in RU
<whitequark> not even "not in stock"
<whitequark> though nevermind, I just realized I have digikey covered
<whitequark> and DK has it in stock
<sb0> what do you need this regulator for?
<sb0> just curious
<whitequark> sb0: I have 24V input and I want to power a water (coolant) pump for my CNC mill
<whitequark> at about 1A it works best
<sb0> constant voltage isn't good?
<whitequark> I dunno actually
<whitequark> they're probably more or less equivalent
<whitequark> in this case
<sb0> and what happens at max voltage?
<whitequark> you mean at 24V?
<sb0> the problem with driving a DC motor with constant current is that if you reduce the load (torque), the voltage and speed will go up
<sb0> yes
<whitequark> oh
<whitequark> oh you're right.
<sb0> if you run out of water, won't it make the motor spin too fast?
<whitequark> I need constant voltage here
<whitequark> it will, and it'll burn
<wpwrak> that should be easy to fix. even an arduino could do that ;-)
<sb0> the problem with pure constant voltage is the current spike at startup, when the motor isn't already spinning
<sb0> but in some cases, the circuit's resistance is enough to keep that current within a reasonable value
<sb0> of course, if you block the motor then, the current will stay high
<wpwrak> so have a controller. monitor voltage. on start, allow for inrush current. then limit voltage (probably needs a low-pass filter). if it gets too high, uncommanded, emergency shutdown.
<wpwrak> and yes, maybe also if the voltage gets too low :)
<sb0> motors are inductive too, which helps limit the inrush current
<sb0> so in a lot of cases, constant-voltage is the best simple solution :)
<sb0> you can also add a slow-acting fuse ...
<wpwrak> i guess you want to control both - current and voltage. regulate one, monitor the other. then you can detect any problems and just cut off. at least that's the theory :)
<whitequark> so contrived
<wpwrak> in russia, it's normal for motors to burn
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<DocScrutinizer05> use a constant voltage with current limiting, and possibly even softstart. All available in very common cheap and simple regulator chips
<DocScrutinizer05> usually with 3 pins
<DocScrutinizer05> maybe for this usecase you prefer a 5pin version, that allows separate control for current limit and softstart
<DocScrutinizer05> the 3 pin versions do no softstart and current limit is usually "hardcoded" and foldback characteristics which you don't really want
<DocScrutinizer05> but actually you might get away with very convenient PWM on 50%, which doesn't even need any heatsink
<DocScrutinizer05> since the motor is inductive, you only need a oscillator driving a power mosfet, and a clamp diode
<DocScrutinizer05> of course you also could use a NE555 and a FET ;-) (sounds familiar, eh?)
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