#qi-hardware IRC log for Saturday, 2014-04-19

DocScrutinizer05WTF?!  unionfs-fuse 0.21   June 200800:00
DocScrutinizer05ok the binary is 0.26, but still...00:15
wpwrakif you're really desperate, you can downgrade to a 0.99pl11/12/14  kernel and add the IFS patch :-)01:03
DocScrutinizer05I'm not exactly in  need of a unionfs, I wanna learn what is the current state of art *when* somebody needs sth like that01:48
DocScrutinizer05I tried IFS, been a nightmare01:48
DocScrutinizer05wtf is pl11/12/14 ?01:49
DocScrutinizer05(tried) yes, back in 0.99 kernel days01:50
DocScrutinizer05looks good, but only looks...06:06
DocScrutinizer05if you wouldn't try to make it auto-rollup, and not insist in it being vertical, it would actually be usable as a *movable* alternative to toolbox06:08
DocScrutinizer05this way it's more like a geeky shelf, not meant to get moved anywhere else than where it is06:08
wpwrakoh, this is gorgeous - homoeopathic pee: https://www.schneier.com/blog/archives/2014/04/overreacting_to_1.html06:50
wpwrakDocScrutinizer05: you'll like this one: http://www.youtube.com/watch?v=keaE7QTKTYE22:04
DocScrutinizer05the cute 14V LEDs22:29
DocScrutinizer053 bucks? still worth it, but only for experts ;-P22:30
wpwraki guess if you dunk is first in silicone, it'll be a lot safer :)22:32
DocScrutinizer05definitely not, it will catch fire in no time22:32
wpwrakwell, there are some high-temperature formulations ...22:34
DocScrutinizer05but you could e.g. mount it on a non-grounded power line (transformer), or a power line with a proper RCD, or simply out of reach of anybody, in 6m height22:35
DocScrutinizer05or parallel the whole 14V LEDs (with tiny series Rs) and operate the whole thing at 12V22:36
wpwrakheh :)22:36
Action: DocScrutinizer05 thought those HV-LEDs were 22V or somesuch22:37
DocScrutinizer05ooooh, wait22:38
DocScrutinizer05graetz rectifier, buffer C22:38
DocScrutinizer0525 :-)22:40
DocScrutinizer05btw it's way less dangerous than that guy claims it was - you are on life wire only with a duty cycle of 50%22:42
DocScrutinizer05then you get at least 20ms to open your grip and get away from that thing that bites you22:43
DocScrutinizer05then otoh it's intermittant DC, and despite what Edison always tried to make the world believe, DC is way worse than AC22:44
DocScrutinizer05AC won't create effective electrolysis, and won't operate but paralyze nerves22:46
DocScrutinizer05DC can break your bones and make your skin look like bubble foil22:47
DocScrutinizer05one end filled with H2, the other with O222:48
DocScrutinizer05AC basically just burns your skin and tissues22:49
Action: DocScrutinizer05 needs to get a few frog legs ;-P22:50
wpwrakthe great classic :)23:01
wpwraka plan B if you can't source a good motor for the vibration alarm23:02
DocScrutinizer05galaxy S5: IP67 :-o23:04
sb0this thing reminds me of a cheap transformer-less "1.7kW 220V -> 110V" adapter that fit in the palm of one hand23:04
sb0it warned against connecting to sensitive equipment like computers, and said it was only good for hairdryers and such23:04
sb0I wonder how it's supposed to work (or not)23:05
sb0yeah :)23:05
sb0so if you put at transformer at the output, you get DC through it?23:05
DocScrutinizer05probably you can choose which direction the fan in the hairdryer spins, by rotating the mains plug 180°23:06
DocScrutinizer05and yeah, motors and transformers LOVE dc23:07
DocScrutinizer05it might work for plain braindead heaters23:07
DocScrutinizer05without motor23:07
DocScrutinizer05but hey, maybe it been "smart" and "muted" every second full sine wave23:08
DocScrutinizer05or it simply been a dimmer23:09
sb0in that case, the full voltage of a complete sine wave will saturate the transformer of any 110V device connected to it and also cause a disaster23:10
DocScrutinizer05then it actually *could* work with transformers and AC motors too, at least with some of them23:10
DocScrutinizer05yep, usually it will23:10
DocScrutinizer05saturated trafo is a nasty thing23:10
sb0I've actually tried to push the voltage of mains transformers23:10
sb0they don't like that23:10
DocScrutinizer05it's usually a sure kill23:11
sb0they begin seriously saturating at like 20% more of the rated voltage23:11
sb0switching power supplies will also fail badly23:12
DocScrutinizer05dunno what's happening to toroid trafos then23:12
sb0well, maybe not if it's a dimmer23:13
DocScrutinizer05actually no, you *can* operate trafos with phase kickin dimmers, not though with phase cutoff dimmers (the new stuff) which are needed for any electronics like LED lamps23:14
DocScrutinizer05and for SPSU it's the question which PFC you got in them, but most of those can do 220V anyway, so any such nonsensical "comnverter" not needed23:16
DocScrutinizer05LED lamps have a SPSU with no PFC at all, and they work finbe with cutoff dimmers23:16
DocScrutinizer05most of them do, at least23:16
DocScrutinizer05some start flickering23:17
DocScrutinizer05and some few LED lamps actually have a PFC and can cope with classical kick-in dimming23:17
sb0what's wrong exactly with transformers and kick-in dimmers?23:19
sb0I never read a good explanation for that23:19
sb0kick-in is when you apply the voltage suddenly within a sinusoid arch, right?23:20
sb0while cut-off is when you apply the start of the arch, then switch off23:20
sb0I'd actually tend to think that classical (kick-in with triac) dimmers would work, but cut-off won't23:22
DocScrutinizer05transformers and kick-in dimmer usually works23:23
DocScrutinizer05cut-off doesn't since it was the same like your age old car engine ignition23:24
DocScrutinizer05the exact inverse algo applies to PSU with rectifier and buffer C, they don't like it much when you apply 300V out of nothing to a discharged buffer C 100 times a second23:25
DocScrutinizer05while they usually tolerate sudden reduction of input voltage to 023:26
DocScrutinizer05thus cut-off for those23:26
DocScrutinizer05kick -in for inductive loads23:26
DocScrutinizer05and a decent PFC shouldn't mind either of both23:27
rohyep. basically you just designe for 'worse power' and dim the output voltage proportional to the input23:31
rohneeds a few cent more for better/more parts. thats the 10% a dim-able led lamp costs in the end23:31
DocScrutinizer05well, a PFC basically emulates a resitive load, by doing buck/boost with no significan input buffer capacitor23:32
DocScrutinizer05the only capacitive component is the RF-filter capacitor to filter away trhe x MHz switching from the PFC23:33
DocScrutinizer05on input23:33
DocScrutinizer05on output side it has a usual huge buffer capacitor for the main SPSU23:33
DocScrutinizer05so a SPSU with PFC are basicall two SPSU in series23:34
DocScrutinizer05with hte first one controlled by input voltage resp current, rather than output voltage23:35
DocScrutinizer05si Vin/Iin is constant23:35
DocScrutinizer05whicj happens to be the definition of a resistive load23:36
DocScrutinizer05I have a FL energysaver lamp that works with kick-in dimmers. dunno what exactly they do23:39
rohsame thing. just ac on the secondary23:39
rohor high-voltage dc and some startpulse23:40
DocScrutinizer05yeah, prolly they simply use the "PFC" style SPSU only, to limit the current that flows through the FL, no matter what#s the voltage across FL23:41
DocScrutinizer05basically a series inductance as in classical FL circuits, just much smaller inductor and a FET or whatever to PWM the current23:42
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