#robotics Logs

Aug 23 2013

00:01 GargantuaSauce and believe me the hexapod is perfectly capable of tearing itself apart, that's why i'm spending some extra time on the software side first
02:56 SquirrelCZECH GargantuaSauce: make hexapod-quadracopter
02:56 SquirrelCZECH and if it is going to look rike real spider -> awesome!
03:11 GuShH SquirrelCZECH: with 10 sec runtime?
03:52 vlt Hello. Newbie here. I want to rotate something like a record player to ~0.1 degrees precision. Do you think a (geared down) stepper motor on the belt and one position sensor on the outer rim will be sufficient or do I need a feedback from the motor shaft anyways and could just take a cheaper DC motor?
03:54 vlt I mean I have no experience. Will a decent stepper perform accurately 80,000 steps or do I need to check that every 20 steps anyways?
03:56 GuShH vlt: yes and no :p
03:56 GuShH what is this for?
03:56 ShH pictures 3d sca
03:57 GuShH bah in that case it wouldn't need to be repeatable, you just reiterate and average out
03:58 GuShH vlt: the geared stepper with an encoder wheel for feedback should be plenty good, what happens when you mis-step, what happens with backlash in general with your application?
04:01 vlt GuShH: Hi, thank you. It's for pointing a laser into a certain direction. So on the turntable there will be a laser pointer, a small mirror with another motor and propably an Arduino. That's all (weight).
04:01 ShH pictures laser guided missiles
04:01 vlt :-D
04:03 GuShH are you sure you can't use some of the MEMS based solutions that are available these days?
04:05 GuShH vlt: ie. galvos
04:05 vlt GuShH: I'm sure about nothing. I'm reading about this only since yesterday.
04:05 GuShH well, since I still don't know what's the actual application, take a look at galvos.
04:05 ShH pokes the
04:06 vlt GuShH: Maybe there are dozens of better ways than I have in mind now ...
04:08 t reads about
04:08 GuShH vlt: MEMS is just another way of achieving the same goal when it comes to galvanometers
04:08 GuShH just on a reduced scale
04:08 GuShH I still don't know what you're trying to do, so it's hard to help you. (be it me or someone else)
04:09 GuShH you can look up laser projector for some hints on galvos
04:12 vlt GuShH: I want to point a laser beam to any angle above horizon. Speed is not critical. Changing from Moon to Jupiter may take a few seconds. Being able to follow the ISS path would be nice.
04:12 vlt I have a tripod, a turntable, laser pointer, mirror, Arduino.
04:12 GuShH so it's laser tracking
04:12 vlt Ah, thanks.
04:13 GuShH the only tracking systems I know of require a prism on the other end heh
04:13 vlt I need motors but also tips which type might be the best here.
04:14 GuShH so you'd be running on basic known data, interpolating the movement most likely and not really tracking but pointing at.
04:14 GuShH because to bounce light and receive it, even on the moon, requires a lot of power.
04:14 GuShH not a chance I think.
04:14 vlt GuShH: Yes. Just pointing. Maybe indoors to a projected sky ...
04:16 GuShH 0.1 degrees would translate to several meters movement after a certain distance (don't feel like running the numbers, but you get the point) so maybe constrain your requirements first to find the best suitable solution
04:16 vlt I didn't expect to "track" Jupiter, LOL
04:16 GuShH good luck with that NASA!
04:17 GuShH I think laser tracking systems to a certain extent are frowned upon by governments IF mounted on some type of vehicle, specially flying...
04:17 GuShH also the reason why GPS is limited in many ways
04:17 vlt Yes, I know.
04:18 GuShH still think you could do some damage if you wanted to
04:18 GuShH seems rather silly.
04:18 GuShH all of these imposed limitations so others will "behave" are silly.
04:19 GuShH vlt: for indoors use a laser projector is ideal
04:19 GuShH well, you can project outdoors using the clouds too, if you have the power.
04:19 GuShH http://elm-chan.org/works/vlp/report_e.html
04:20 GuShH focus on the galvo xy scanning portion
04:20 GuShH on low speed, low resolution, it's not as hard as it sounds.
04:21 GuShH you should see how cheapie laser lights are made, it's laughable.
04:22 GuShH since you wanted feedback, closed-loop it is.
04:23 GuShH vlt : a possible starting point http://www.instructables.com/id/Arduino-Laser-Show-with-Full-XY-Control/
04:23 GuShH don't tell anyone I linked to that site.
04:24 GuShH not an expert, but I guess those are resonant open loop
04:24 GuShH and in theory harddrives are also a good starting point
04:25 vlt GuShH: I don't know how to get 180x180 degrees with these galvos.
04:26 GuShH you sure are picky
04:26 vlt Maybe ;-)
04:27 GuShH So maybe you'd want to build a frame with a couple gimbals (similar to a gyroscope)
04:28 GuShH but you can't have it all... you'll need to trade between angle, precision, etc.
04:28 vlt It's an educational project, so I still like the turntable version a bit more because you can see what actually happens.
04:28 GuShH have a small person inside a black box and hand him / her a laser pointer, done.
04:29 GuShH that's how some automatas were made in the early ages :p
04:29 vlt ROFL
04:29 GuShH ie. the chess playing automata had an actual human inside.
04:29 GuShH heh
04:29 vlt Yep
04:32 GuShH seems everyone is just using servos and aren't concerned with precision or step size
04:34 vlt hmmm ... servos
04:34 t r
04:34 GuShH not ideal for anything but "look, it moves"
04:35 GuShH look at reduction steppers, but you won't find anything "good enough" on the cheap, however a 512 step reduced stepper is going to give you a lot more satisfaction than a cheap servo, they're just slower.
04:37 GuShH the thing is, you can sustain torque with either one of them rather easily.
04:38 GuShH if you go open-loop there's no need for feedback, it simply assumes everything is in working condition and it doesn't account for backlash or other mechanical issues.
05:32 RifRaf I love Fridays, cause Fridays are great
05:41 GuShH RifRaf: that's twitter material
05:41 RifRaf its aussie hiphop
05:42 RifRaf i love that song to start the tunes flowing
06:56 RifRaf GuShH, i bet you feel like this some days http://www.youtube.com/watch?v=9PfVfYppfdU
07:39 GuShH RifRaf: hrmm
07:40 GuShH but is it my fault?
07:41 theBear you can't be blamed for breaking the rubber'
07:41 RifRaf :)
07:42 GuShH o.o
07:43 theBear http://www.youtube.com/watch?v=3K8yFTKARug this is more my speed
07:44 RifRaf GuShH, was not saying its your fault, some shit just happens everyday
07:44 theBear damn, if that shit happens everyday, you're living life to the max !
07:44 RifRaf theBear, neverland was awesome, but damn i was tired when i woke up, was 4 days of party party in a night :/
07:45 theBear hmmm... took me 6 hours to get to sleep, but i slept for 14, so not bad
07:45 RifRaf so looking forward to the next chapter
07:45 RifRaf and tomorrow gonna go and let loose, a real party for a change
07:46 theBear fwoo, i haven't been to a real party for a long time
07:46 RifRaf yep been a few months here too
07:46 theBear hehe fool, i said a long time
07:47 RifRaf theBear, your video was a little bit odd
07:47 theBear maybe 8 months, and even that was a grownups party, sure there was a hookah and a handfull of uppers downers dreamers laughers, but nothing serious
07:47 theBear totally :)
07:47 theBear tho i will admit yours was perhaps the finest the genre ever had or will have to offer
07:48 RifRaf yep, i love good old school aussie hiphop
07:49 RifRaf funkoars on now
07:49 theBear heh, that ain't old, but you probly never heard the old 'cos its so horrible
07:49 GuShH I thought aussie hiphop was like unicorns
07:50 theBear no, that's post 2000 "r&b"
07:50 theBear pfft, rythym and blues my ass ! it's bad samples and poppin caps
07:50 theBear in their homeboys bo-bos
07:51 theBear https://sphotos-b-iad.xx.fbcdn.net/hphotos-frc3/1235042_659268960751487_442371931_n.jpg
07:51 theBear https://sphotos-b-iad.xx.fbcdn.net/hphotos-ash3/1148845_653786544633062_881752911_n.jpg
07:51 theBear there ya go, anyone that doesn't cheer up may as well just kill themselves right now
07:53 RifRaf :)
07:54 GuShH heh
07:54 theBear good boys ! you deserve to live another day
07:54 theBear and i deserve another coffee, almost overflowing with cream
07:55 GuShH had to head to downtown ... but every single public transport in this friggin country is on strike
07:55 GuShH so yeah RifRaf is right...
07:56 RifRaf lol
07:56 GuShH and because they also casually close the roads, you can't even head over by any other vehicle
07:56 GuShH and I don't seem to own a helicopter... as far as I know.
07:56 GuShH I think this is why the term FML was invented?
08:01 theBear i don't wanna do that to your lady !
08:02 RifRaf yo mama
08:02 RifRaf http://www.youtube.com/watch?v=QYf2Dh71RgY
08:02 theBear JO MAMA !
08:06 GuShH who momma?
08:08 RifRaf i don't think there has been anyone as original as butterfingers in a long while
08:09 RifRaf http://www.youtube.com/watch?v=dfxY6jMinPQ
08:09 theBear http://www.youtube.com/watch?feature=player_detailpage&v=UUBnW4yzOA0#t=175 give it 20 or 30 seconds, you'll see the relevance
08:09 RifRaf GuShH, does AR have any equivalent?
08:10 theBear no equivalents and no equals !
08:12 GuShH don't know
08:12 RifRaf because there is none :)
08:14 theBear damned straight !
08:16 theBear ths world is all topsy turvy ! all the cigarette advertising in the world doesn't make me wanna smoke, but every damned movie i see shows people with more cigarettes than me !
08:17 RifRaf must admit my cigarette intake has increased in recent times
08:17 theBear not that i'm saying they should ban depictions of people, OR cartoons smoking, just that billboards and advertisments are irrelevant
08:18 theBear and yet you have seen ZERO advertising !
08:18 theBear you should join the pro smoking lobby like me !
08:18 RifRaf yep
08:18 theBear something like itsmychoice.com.au
08:19 RifRaf http://www.youtube.com/watch?v=3hbu0ERdQGk
08:19 RifRaf bad habits
08:20 theBear we need a youtube bot in here so i don't stop the movie for shit i seen before
08:24 RifRaf am listening to the albums here, but cannot help but share a decent song via youtube when it plays
08:24 RifRaf because its Friday :)
08:25 theBear meh, weekends don't mean the same thing when yer retired
08:25 RifRaf i guess, you should fly over, looks like a big one tomorrow
08:25 theBear yeah, retired people got loads of money to party on the other side of the country
08:26 RifRaf getting picked up at 10am
08:26 RifRaf :(
08:26 theBear and much as i like you, i got lovers and people i lived with for almost 10 years that deserve visits
08:26 theBear some of them aint been seen since they had babies :(
08:28 RifRaf gonna get me kidneys shifted
08:29 theBear speaking of having babies eh
08:30 RifRaf lol, look out mamas, rifraf is on the prowl
08:31 theBear i had the most glorious couple weeks with a mama in forster a year ago
08:31 theBear plus best man with the grooms sister, pure gold !
08:32 GuShH theBear: your babies?
08:32 ShH bl
08:32 GuShH it all sounds beary wrong
08:32 theBear don't be silly, i don't have babies
08:36 [1]RifRaf woah, just BSOD'd here
08:37 GuShH hahaw!
08:37 GuShH theBear: that you know of
08:37 theBear nah, i keep an eye on these things... well, there's one possible loose cannon, but there's zero chance it'll ever find me
08:37 theBear heh, and it'd be 20 or so by now
08:37 GuShH lol
08:38 GuShH POSSIBLE?
08:38 theBear i was young, what can i say ?
08:38 GuShH :o
08:40 RifRaf was about time for a reboot anyways i think
08:41 RifRaf thank goodness for sd printing
08:43 GuShH poop
09:04 fRaf considers shaving face, was saving it for when i wanted to lose a few y
09:05 RifRaf is the only grey on me head
09:48 GuShH RifRaf: took the quill off, the diameter on the cast iron body was machined way too big, it's faulty
09:48 GuShH on the other hand, 4 bearings... so it's a good design, but a faulty unit
11:16 GuShH 0.20mm shim removes the play on the quill, doesn't sound like much but it's uneven so the only solution would be to machine the quill down at least 1mm, oversize the body diameter and machine a brass bushing... not gonna happen. let's see if they accept a return tomorrow, otherwise I'm stuck with this POS.
11:19 Tom_itx or get a bigger OD bearing
13:35 KongfuPanda hello :)
13:36 KongfuPanda I just bought some servos
13:37 KongfuPanda but it seems the have some "stuff" inside, I think it's dried oil
13:37 KongfuPanda what should I do? send them back?
13:37 KongfuPanda or heat it up to make the oil melt or something?
14:08 LoRez why did you open them?
14:33 theBear it's grease, leave it be
19:11 robotustra finally
19:11 robotustra at home
19:43 rue_house I wish google had a block list, so you could, at a profile level, block certian sites, like answers.com from your results, permanently
19:43 theBear you gotta be bigger than the chinese govt. for that feature
19:49 rue_house whats what stupid datasheet page that always says it dosn't have the one your looking for?
20:31 robotustra http://www.youtube.com/watch?v=NjvxqouojNg
20:39 Tom_itx anybody familiar with the google toolbar on ie?
20:39 Tom_itx i need to clean out it's history
20:40 robotustra did you watch porno at work?
20:40 theBear sometimes
20:40 Tom_itx not my pc, i never use it but working on it
20:40 theBear but i'm retired now
20:42 robotustra nither job nor porno...
21:56 Tom_itx the file is damaged...
21:57 Tom_itx dunno how to find those
21:58 theBear oh, i've still got porno, don't worry about that
22:51 MrCurious whoa! robotic lawn mower!
23:08 rue_house hmm
23:53 RifRaf 3 hours into a 12 hour print http://imagebin.org/268599
23:56 rue_house you have it on a UPS?
23:57 RifRaf no, but no usb, sdcard
23:58 RifRaf printing at 0.12mm to get some quality
23:58 RifRaf skys look clear
23:58 rue_house maybe this weekend we can work on mine
23:59 rue_house I was told by another chap that it will not move untill the axies are initialized
23:59 RifRaf yep, the print will end up 190mm high for the boots object
23:59 rue_house shouldn't you be doing a print that high in segments?