#qi-hardware IRC log for Wednesday, 2013-10-23

apeleteGood morning08:20
apeletemth: I saw an interesting way of representing a number in the programming manual last night, been thinking about it on my way to work today08:23
apeletethe number was written 0x0000150008:23
apeletein hex08:23
apeleteand then the same value was written as H'1508:24
apeletemth: what is that H'15 notation and how do you read it ? I don't remember ever seeing that before08:26
DocScrutinizer05wpwrak: nice article10:14
wpwrakeintopf: that array of transceivers looks strangely powerful ;-)10:24
eintopfwpwrak: yea, I have a little usb powering problems sometimes10:30
eintopfwhen my brother turns his lights on in the neighboor room10:30
eintopffunny :)10:30
wpwrakthat seems odd. the critters don't draw much power10:30
eintopfwpwrak: maybe my usb cable is too long and i put too much devices on it10:34
eintopfput I think it's the cable10:34
eintopfall my usb devices makes a reset10:34
eintopfI change a little bit my usb setup now10:37
eintopfusing integrated usb hub in my monitor, maybe I get more power10:37
DocScrutinizer05eintopf: CFL lamp?10:46
DocScrutinizer05or LED?10:46
DocScrutinizer05or even FL10:46
DocScrutinizer05I think when your usb devices reset when some lights are turned on, then that's quite usually an issue of EMI razher that power brownout (unless the lights are 1000W halogen incandescent)10:47
eintopfhalogen lamp10:47
DocScrutinizer05hmmm10:48
DocScrutinizer05those actually have quize a bit of inrush current to heat up10:48
eintopfwhen I had a analog connection, I saw this too10:48
DocScrutinizer05could you "record" the 50 (60?) Hz powerline from e.g. a magnetic mic or coil placed near to a transformer, and feed this to the mic input of your PC?10:50
DocScrutinizer05assuming you have no true storage scope10:50
DocScrutinizer05I'd be highly interested in the five seconds around the lamp-on event10:51
DocScrutinizer05you also could use the line-in and a 12V AC adapter plus a 50/1 resistor voltage divider10:51
eintopfoh, ehm10:53
eintopfwhen I have time10:53
eintopfyou want that I do some record on my microphone input?10:53
DocScrutinizer05audacity makes for an excellent low frequency storage scope10:53
eintopfto sampling the light on thing?10:53
DocScrutinizer05yep10:54
eintopfand where should I put the wire?10:54
DocScrutinizer05I'd be interested in what kind of brownout (or other) event on mains line causes USB devices to reset10:54
eintopfDocScrutinizer05: ah ok10:55
DocScrutinizer05like I said, most accurate and simple and foolproof design is a 12V AC power supply (some DSL routers or modems etc have such), and user a voltage divider from a 5k and a 100Ohm resistor, then feed the both ends of the 100R to the line-in contacts of the PC10:56
DocScrutinizer05make sure the 12V is not galvanically coupled to protective earth10:57
DocScrutinizer05from your photo I gather you should know what i'm talking about ;-)10:57
eintopfa little bit10:59
eintopfI know voltage divider10:59
DocScrutinizer05that's about all it needs :-)11:00
eintopfand I have some 12 AC power supply here, of course11:00
eintopffrom old routers which I put my mobile phone rs232 on11:00
DocScrutinizer05yep11:00
DocScrutinizer05AC is inportant11:01
DocScrutinizer05im*11:01
DocScrutinizer05you'll want to test that power supply with a multimeter anyway, to make sure it has no connection from secondary side to protective earth of mains11:02
DocScrutinizer05so you same time can check if it's actually AC, or maybe DC11:02
eintopfah, I have a multimeter here11:02
DocScrutinizer05given you have some resistors at hand (or maybe a 47k potentiometer). the most troublesome component of the whole thing is the cable with 3.5mm plug to plug into line-in of PC11:04
DocScrutinizer05the rest are lab probe wires ;-)11:04
eintopfI have resistors, potentiometer I have everything11:07
eintopfbut I don't know which resistor group I have11:08
eintopfbut I can connect them11:08
eintopfin row11:08
DocScrutinizer05use your meter to check size11:08
DocScrutinizer05size? value? meh, resistance11:08
eintopfbut I try this at weekend11:09
DocScrutinizer05if you only have identical ones, connect 10 of them in series, make sure it's a total resistance of 500<R<500k. and solder/clib the both wires of the line in to one of those 10 resistors11:10
DocScrutinizer05line in should be fine with anything from 50mV to 2V11:11
DocScrutinizer05it shouldn't smoke up even with 12V, but you rather try to avoid testing that ;-)11:12
DocScrutinizer05or use this approach: http://www.vlf.it/polard/rcf.html11:16
eintopfI need a digital storage oscilloscope11:18
DocScrutinizer05hehe11:22
DocScrutinizer05a PC is absolutely great for such low frequencies11:22
DocScrutinizer05particularly when you don't have any special needs regarding triggering11:23
eintopfyeah for <= 22 khz, or?11:23
DocScrutinizer05I think soundcards can probably usually go as high as 100kHz11:23
eintopfah11:23
DocScrutinizer05depends11:23
eintopfI though because these 44khz which human can hear or something else11:24
eintopfbut I had a idea some time ago11:24
eintopfto use a atmega32 or something else11:24
DocScrutinizer0544ks/s is  usual sampling frequency based on physioacustics11:24
eintopfand capture something from adc11:24
eintopfand save it on my pc and use gnuplot for plotting11:24
DocScrutinizer05the ADC can go way higher though11:25
DocScrutinizer05most cards offer 96k sampling freq11:25
DocScrutinizer05some go even higher11:25
eintopf07:01.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 07)11:26
eintopflove this card11:26
eintopfon onboard I hear too much usb traffic :)11:26
DocScrutinizer05yeah, S/N often is poor for the embedded audio codecs11:27
DocScrutinizer05though usually mostly a problem for mic input, less for line-in11:27
eintopfin my last company which I worked11:28
eintopfI made some manual audio tests11:28
eintopfthen I heard something, I say ok it wasn't terrible11:28
eintopfbut then I turn on the iperf tool11:28
eintopfthe complete ethernet bus was heard11:29
eintopfand terrible loud11:29
DocScrutinizer05haha11:29
DocScrutinizer05audio-in is one of the features only poorly tested on PC11:29
eintopfyea11:30
DocScrutinizer05I guess manufacturers could get away with soldering dummies on the PCB11:30
eintopfmhh, I am only a little software guy11:30
eintopfbut a little embedded software guy11:31
DocScrutinizer05rarely anybody ever using it (except of course for old [non-USB] headsets, and VoIP/skype)11:31
DocScrutinizer05sorry, busy suff: http://talk.maemo.org/showthread.php?p=1381926#post1381926  bbl11:32
DocScrutinizer05stuff even11:32
DocScrutinizer05o/11:33
wpwraknice typo ;-)12:01
eintopfwpwrak: http://en.wikipedia.org/wiki/Noise_generator for anelok, but I think you know that already13:26
paul_boddieqi-hardware.com is back! Thanks, wolfspraul, xiangfu, or whoever you are! :-)15:59
qwebirc88555Hi..18:47
qwebirc88555I'm from Brazil, and I'm very interested in the Ben Nanonote18:50
qwebirc88555But I can't find a place to buy it...18:51
mthafaik there were quite a few produced, so there might be some left18:54
mthI don't know who would have them though18:56
mthwolfspraul: do you have a warehouse full of Bens somewhere? ;)18:56
cdehttp://blog.elphel.com/2013/10/fpga-is-for-freedom/ "But this shift to Free Software does not yet apply to the main part of the software tools  tools for the FPGA or programmable logic (PL) in terms of Zynq development."18:57
cdean interesting article18:57
qwebirc88555If I heard about this project before...18:57
qwebirc88555Nothing serious, just a hobby, but I'm trying to learn about programming... This is the ultimate geek project..18:59
cdeno, Skynet is the ultimate geek project18:59
cdehowever the Ben is very cool18:59
cdedid you see my query btw?18:59
qwebirc88555No, i didn't, this crappy computer has problems...19:02
qwebirc88555Pandora is too expensive... Ben Nano would be perfect...19:06
wpwrakqwebirc88555: pulster.eu may still have some. a bit awkward to buy from there, though19:28
dos1awkward? why?19:47
wpwrakno credit card. also, some of the site is in german only.19:50
qwebirc88555Only Paypal19:55

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