wpwrak | zrafa: btw, did you get somewhere with the simulator now ? | 11:47 |
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wpwrak | hmm, nouveau driver acting up, it seems. or maybe it's the hardware that went klingon | 12:44 |
wpwrak | let's see if i can close the xchat connect dialog ... | 12:45 |
wpwrak | phew. this time it worked | 12:45 |
wpwrak | well, for a few seconds at least | 12:48 |
wpwrak | hmm, strange error patterns | 13:02 |
wpwrak | e.g., start mocp in xterm on the nividia -> system freezes | 13:03 |
wpwrak | weirder: switched primary to ati, and that one had a hang, too | 13:04 |
eintopf | mocp :o | 16:25 |
whitequark | wpwrak: testing the limits of my camera. https://i.imgur.com/kF6JRVq.png | 17:23 |
wpwrak | whitequark: is this a new one ? or the SLR you bought already a good while (> 1 year ?) ago | 18:23 |
whitequark | wpwrak: actually that's even a bad pic, let me upload a new one in a moment | 18:36 |
whitequark | same camera though | 18:36 |
whitequark | wpwrak: http://lab.whitequark.org/notes/2014-11-13/photographing-pcd8544/ | 19:03 |
wpwrak | nice :) now, on to reverse-synthesizing the netlist :) | 19:06 |
whitequark | well, resolution's not high enough | 19:07 |
whitequark | I'm going to get an optical microscope. | 19:07 |
wpwrak | DocScrutinizer05: i guess that's the sort of camera you should have :) | 19:27 |
DocScrutinizer05 | yes, I know | 19:33 |
eintopf | whats the correct word for a potentiometer which doesn't block | 19:36 |
eintopf | newbie question :-) | 19:36 |
eintopf | I mean I want to measure the angle of a 360 degree stick mounted at the end at the potentiometer - like this http://walter.bislins.ch/physik/media/Pendel.png | 19:39 |
wpwrak | "rotary encoder" ? ;-) | 19:39 |
wpwrak | (but such an encoder has has discrete positions) | 19:39 |
DocScrutinizer05 | such thing doesn't exist | 19:40 |
DocScrutinizer05 | yes, you can get encoders, but they rarely ever use the potentiometer approach | 19:41 |
eintopf | ah okay, so no potentiometer | 19:41 |
eintopf | http://en.wikipedia.org/wiki/Rotary_encoder | 19:41 |
DocScrutinizer05 | rather two 90° phase skewed adjustable capacitors, or recently rather digital encoders | 19:42 |
eintopf | but I need more granularity than 8 bit | 19:42 |
DocScrutinizer05 | when you need more resolution than 8 bit, then how about using a laser mouse looking on a ring mounted to the axis, and have an index marker of some sort (e.g. a hole in ring and a light path sensor) to keep track of the absolute position | 19:44 |
eintopf | this sounds too complicated for me | 19:45 |
whitequark | that's actually a very high-resolution method | 19:46 |
whitequark | you have mice upwards to 8000dpip | 19:46 |
whitequark | *dpi | 19:46 |
DocScrutinizer05 | of course you also can do a binary encoder, but that's for sure even more complicated. BTW usual potentiometers have a resolution quite a bit less than the requested 9 bits | 19:46 |
whitequark | and you can make radius as high as you can possibly want | 19:46 |
DocScrutinizer05 | whitequark: exactly | 19:46 |
whitequark | i.e. it essentially offers unlimited resolution | 19:47 |
DocScrutinizer05 | and shouldn't be any complicated to build either | 19:47 |
whitequark | though at some point accumulating error will be a big problem | 19:47 |
DocScrutinizer05 | optical mice afaik have no systemic accumulating error | 19:47 |
eintopf | what the hell is a light path sensor | 19:47 |
whitequark | DocScrutinizer05: of course they do | 19:48 |
DocScrutinizer05 | a thing made of an LED and a light sensor, both form a gap | 19:48 |
whitequark | it traverses 1mm, it says it traverses 1.1mm | 19:48 |
DocScrutinizer05 | that's not systemic accumulating error, that's maybe a calibration factor | 19:48 |
whitequark | mmm | 19:49 |
DocScrutinizer05 | afaik the sensor works with pattern recognition and that has no _error_ | 19:49 |
whitequark | well, there are two concerns | 19:49 |
DocScrutinizer05 | when you move the target a million times back and forth for 10mm, it should still shop position:0.0000000 | 19:49 |
DocScrutinizer05 | show* | 19:50 |
whitequark | that'd be a different kind of error | 19:50 |
DocScrutinizer05 | everything else is not error but calibration | 19:50 |
DocScrutinizer05 | or error introduces by noise/jitter, but that's still not accumulating in this concept afaik | 19:51 |
DocScrutinizer05 | iow once you calibrated the ting to show 10000cm as 10000cm, it's as accurate as it gets: 1/8000 inch | 19:52 |
whitequark | yeah, that makes sense | 19:53 |
DocScrutinizer05 | the rest are non-linearities but no accumulating errors | 19:53 |
eintopf | you mean with index marker some point like 0 degree's and the mouse detects all movements? | 19:55 |
DocScrutinizer05 | yes | 19:55 |
eintopf | this really working on long distance? | 19:56 |
eintopf | s/this/do this/ | 19:56 |
DocScrutinizer05 | such concept obviously needs a setup procedure after power up | 19:56 |
DocScrutinizer05 | where's a long distance in this design? | 19:56 |
DocScrutinizer05 | the mouse sensor should hove a 0.5mm over your ring | 19:57 |
DocScrutinizer05 | hover | 19:57 |
eintopf | ah, yes | 19:57 |
DocScrutinizer05 | or even glide on it | 19:57 |
eintopf | I understand | 19:57 |
DocScrutinizer05 | after poer up you need one full turn of axis to make sure the index marker passed by | 19:58 |
eintopf | s/I understand/I see | 19:58 |
DocScrutinizer05 | a second turn can auto-calibrate the mouse data, you know it's been 360.000° when index marker passing by a second time | 19:59 |
DocScrutinizer05 | when your mouse reported 36000 clicks until that 2nd index event, you know it has a resolution of 1/10 degree | 20:00 |
DocScrutinizer05 | err 1/100 | 20:00 |
DocScrutinizer05 | such sensor would be *very* fine grained and accurate | 20:01 |
DocScrutinizer05 | and you can build it for 25 bucks from material you got in your garage ;-) | 20:03 |
whitequark | 25 bucks? how about zero | 20:04 |
eintopf | okay, okay. This sounds like a nice solution. Thanks | 20:15 |
eintopf | now I need to figure out how I can control the motor of my old scanner device and place a stick on it with some mass at the end. But maybe the motor control is too slow | 20:16 |
eintopf | I am sure I could do that with libusb and some control messages | 20:17 |
eintopf | for controlling a inverted pendelum... | 20:18 |
eintopf | s/a inverted/an inverted | 20:18 |
kristianpaul | https://www.indiegogo.com/projects/lantern-one-device-free-data-from-space-forever | 21:15 |
kristianpaul | What that thing have to no need a dish at all.. | 21:15 |
wpwrak | grmbl. spamprobe started to hang. i don't like the possible pattern. new database, new luck ... for now ... | 23:35 |
wpwrak | hmm. nvidia degradation killed xclock. no update to small to potentially cause a hang. i guess i'll go shopping tomorrow ... | 23:52 |
zear | kristianpaul, your gps device also doesn't need a dish :) | 23:59 |
--- Fri Nov 14 2014 | 00:00 |
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