#robotics Logs

Feb 05 2013

00:29 RifRaf hello world done, so compiler works, its dev c++ but it compiled ok from the C example
00:30 Jak_o_Shadows You know, for the amount of cygwin packages you downloaded, you could probably have downloaded linux.
00:32 RifRaf i have linux on other computers but not working, you think i should get one going for this?
00:33 RifRaf the first thing i learnt is that even hello world uses a library called stdio.h , so you all use libraries as well :P
00:33 Jak_o_Shadows No, you dont need to. May work, may not work, so just use what you know/have
00:34 RifRaf well this c++ is compiling and on same system i am doing all the avr stuff so will stick with it
00:34 RifRaf did not install cygwin yet, will when its required
00:42 Triffid_Hunter RifRaf: stdio is headers for the standard C library which all C programs automatically get linked against unless you explicitly say not to
00:42 Triffid_Hunter RifRaf: there's lots of std* headers, C library provides lots of low-level stuff
00:46 RifRaf Triffid_Hunter thanks, was just defending my use of using libraries to make avrs easier to use
00:48 RifRaf C course going ok so far and making sence
00:50 rue_house you need libraries to get anywhere, the better libaries you have, the better you can get easier
00:50 RifRaf indeed
00:51 rue_house I find that most people code bad and make buggy libraries }:\
00:51 RifRaf i should be typing these examples and not copy paste eh
00:52 rue_house I tell my students "there is no cheating"
00:53 rue_house as in, this is life, its not possable to cheat
00:56 RifRaf yes yes, even debugged my own typos and missing ;
00:56 RifRaf on a roll
01:22 RifRaf music break http://www.youtube.com/watch?v=YS-j1AiTqgk
01:23 RifRaf is a new clip from kifs boyfriends band
01:29 RifRaf is shot around your neck of the woods Triffid_Hunter
01:48 RifRaf damn cannot even do the simplest algebra anymore :/
01:56 RifRaf did it. made a celcius to fahrenhiet convertor that works, upto chartper 1.3 but need a break
01:56 RifRaf celsius* made that mistake a few times :/
01:57 RifRaf have learnt heaps already on how to make some changes to my avr code
02:10 Triffid_Hunter RifRaf: on an unrelated note, want to post me an R/C rolling chassis?
03:34 Jak_o_Shadows If you don't consider libraries, you're an idiot
03:38 Rif Jak_o_Shadows i did learn some C tonight, and will keep goin, the words just start spinning on the screen after a while though
03:38 Tom_itx heh
03:39 Rif am upto the for statement, page 15 or so, but need to leave it ther till morning i reckon
03:41 Tom_itx you may run across that immediate if i was showing you
03:41 Tom_itx i sorta forgot the syntax
03:41 Rif oh yes what you posted earlier, i must look
03:41 Jak_o_Shadows I always screw up the syntax for for loops
03:41 Rif but the morning may be better, have beethoven playing now and the rain coming down outside
03:43 Rif made a celsius to fahr convertor, so that was a big step, actually had to think proper
03:43 Tom_itx saw that
03:43 Rif well i'm proud of it :)
03:44 Tom_itx stay motivated to learn it
03:44 Tom_itx then you can answer all my questions
03:45 Rif yep, small steps to start, apparently getting stuff compiling and understanding the basic errors is a big step, but being doing that for years already
03:48 Rif just dunno how they make up all that code, happy to compile it and make a few adjustments
03:49 Rif disk magnets 1mm OD x 0.5mm thick
03:50 Tom_itx http://tom-itx.dyndns.org:81/~webpage/avr/c_bits/bits_index.php
03:50 Tom_itx you should get a good understaning of that along the way as well
03:51 Rif yes read the first section, will get there over the next few days hopefully
03:52 Tom_itx you'll find yourself using those alot
03:52 Rif i just want the basics for now, one week of C, if that don't get me anywhere nothing will]
03:52 Tom_itx those are part of the basics
03:52 Rif and will resign myself to making inanimate robots
03:53 Rif or just go fishing again
03:53 Rif which i am gonna do this weekend
03:53 Tom_itx i gotta soak it in a little at a time. i don't think i'd do well with a crash course
03:54 Rif and take the C book on me tablet
03:54 Rif is there a way to compile on an android?
03:54 Tom_itx i'm not sure
03:54 Jak_o_Shadows if you install linux on it.
03:54 Tom_itx possibly
03:54 Rif i crash course everything tom]
03:54 Rif Jak_o_Shadows isn't android linixy?
03:55 Jak_o_Shadows Yes, but it's hidden fairly deep
03:58 Rif well reading the book will have to do
03:59 Rif i wish one of you people would at least install and have a look at webbotlibs
04:00 Rif if not just to see a different way of doing things
04:01 Rif opens up an easy way to explore so many new sensors, and obviously you still have to code the stuff yourself
04:02 Rif thats where i been coming unstuck, but is all good, knowing stuff is hooked up right is a big start
04:03 Rif http://www.ebay.com.au/itm/170383676472?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1768wt_806
04:04 Rif gonna make a smaller 3dof gripper with them
05:30 MrTrick Rif: Why micro servos?
05:30 MrTrick I suppose for the gripper motors it makes sense, but for elbow/shoulder too?
05:54 theBear i think that's a combination of what he had lying around and proof of concept for strength/power
06:32 GuShH_Lap theBear: rif + proof of concept?
06:32 GuShH_Lap o.O
06:33 GuShH_Lap that's like saying theBear is a jehovah witness
06:33 theBear to some of us proof of concept means making something work :) even the more scientific 'stralians amongst US (like you, me, everyone here) often prefer doing things semi technical semi rule of thumb :)
06:33 theBear heck, even that rue guy doesn't overdo maths unless he has to :)
06:34 GuShH_Lap oh well
06:34 GuShH_Lap theBear: the vreg on the cheap security camera died again, this time "the other one" did
06:35 GuShH_Lap they use 2 in series to step down from 12v to 5v (1 8v and 1 5v)
06:35 theBear hey, we get stuff done :) scoping common mode chokes/balun kinda stuff a few days ago turned into a time-taking nightmare, and i only got a few % better (usable) results than i had before :)
06:35 GuShH_Lap problem is, when the 12v floats higher due to an unregulated supply, one regulator is bound to go poof
06:35 GuShH_Lap I ended up using a big ol 7805 in there, but it's getting quite hot, maybe it's oscillating... I just can't be bothered anymore with that camera
06:36 GuShH_Lap not worth it. they're a piece of crap
06:36 theBear interesting.. i've got one camera of unknown origins, just bare 2pcb stacked small kinda thing, afaict without excessive reversing of it, all onboard regs are healthy, but it only seems to run on around 6-6.5v into the pcb (unheard of) and even then one onboard reg gets almost silly hot....
06:36 GuShH_Lap the IR module is half dead, works if you wiggle the cable around or touch it on the right place....
06:37 theBear now you mention it, i wonder if a hidden onboard reg IS dead, that'd explain why it gains a dead pixel every 2-4 weeks
06:37 GuShH_Lap resoldering didn't help, at least one third of the LEDs are dead already
06:37 GuShH_Lap the camera works, it's just not ideal heh
06:40 GuShH_Lap theBear: silly webcam shot of it http://i49.tinypic.com/2d13i8g.jpg
06:40 GuShH_Lap only one pcb, horribly soldered no silkscreen...
06:42 GuShH_Lap got a slightly better one... and it came with a dead dc connector, well the cable is.
06:42 GuShH_Lap really annoying.
06:43 GuShH_Lap http://i49.tinypic.com/e0low8.jpg
06:43 GuShH_Lap they're not even weatherproof
06:44 GuShH_Lap there's an o-ring seal on one of them, but then there's an open hole for the microphone, silly chinese...
06:44 theBear buddy recently got one that's kinda a orb sitting in a matching swivel thinger, amazingly effective ring of ir leds with a light sensor on/off.. coincidentally spotted several identical ones around for sale recently... it seems good
06:44 GuShH_Lap the IR rings are great on these, they just die...
06:44 GuShH_Lap coincidentally due to the lack of regulation on them
06:44 GuShH_Lap they are plugged direclty to the 12v
06:44 GuShH_Lap and in series
06:44 GuShH_Lap well, series of series :p
06:45 GuShH_Lap parallel series? well you get it.
06:45 GuShH_Lap "power 12vdc / 1a"
06:45 GuShH_Lap I measured 280mA peak on them, at full darkness...
06:45 GuShH_Lap go figure.
06:46 GuShH_Lap that's as far as I'll ever go with cheap cameras, not worth it
06:46 theBear mmm, hard to judge without knowing series/parallel wiring, unless you mean per led, whcih if it's modulated isn't THAT outrageous, pretty sure ir remote leds are rated for low duty pulsing at over 300mA
06:47 GuShH_Lap let's say 12v worth of series LEDs times N amount of strings required to achieve the amount of LEDs needed for that ring
06:47 GuShH_Lap theBear: they're driven by transistors which in turn are driven by an LDR
06:48 theBear i don't really know about my cams, they all come to me thru various non-payment paths... i know one of them is non-cheap, the caseless one is hard to say, and i assume the b+w reversing cam (but VERY waterproof, like fishtank safe) is pretty cheap, tho it sees ir great being b+w, and has a nice wide semi fisheye lens
06:48 GuShH_Lap it's not even a schmitt trigger
06:48 theBear heh, that's a bit shitty, this one is definately hard on/off, and a glance without looking at tracks suggests schmiddt
06:48 GuShH_Lap well they "modulate" to spend less power, in theory
06:48 GuShH_Lap it's just a linear fade
06:49 GuShH_Lap which is OK except for the fact there isn't even a zener in there to protect from over voltage
06:49 GuShH_Lap or a fuse..
06:49 theBear yeah, that's not special.. if yer talking about generally/ir remotes, they modulate both to save power, and to raise 'brightness' ... an ir remote might be say, 50% duty cycle on a given code, but MUCH brighter than 200% of linear led rating, and they last forever
06:50 theBear mmm, i suppose with non-reg'd supplies being common for cams, unregd leds is kinda dangerous overpower wise
06:50 GuShH_Lap they are constantly lit on these cameras, it's not PWM :(
06:50 GuShH_Lap even if they were free cameras I wouldn't use them outside
06:50 GuShH_Lap nor depend on them....
06:51 theBear reminds me, i said i'd give him both basic cat5 baluns for this (i can wind up ones that work fine for 50' or more without thinking from psu scraps) but a psu, gotta measure the draw so i can give him a small one :)
06:51 GuShH_Lap but crap, ip (wifi) cameras are still too expensive
06:51 GuShH_Lap at 60 dollars a pop...
06:51 theBear they are, slowly getting mroe reasonable tho, 5 years ago $250 was cheap
06:51 GuShH_Lap plus I don't like wireless cameras
06:51 GuShH_Lap you still need to run power to it :p}
06:52 GuShH_Lap I might end up using an AT or ATX for the supply
06:52 theBear yeah, half eliminates the point, but particularly in flat/not-your house situations it makes things a lot more likely to be do-able
06:52 theBear at the moment all (3) of my home cams get power from the pc that receives them
06:52 GuShH_Lap but if I install one camera outside, I may want two (one facing to each other)
06:53 GuShH_Lap problem is, the proper locations require a lot of wiring...
06:53 GuShH_Lap I'm still digging conduits for the phone line heh
06:53 GuShH_Lap might run some extra pairs for a camera or two... we'll see
06:54 theBear mmm, i dunno the situation, i find fisheye lenses can help a lot, get very close to 180deg, and if you can arrange so you don't need amazing quality (ie. recognizable faces) in the fringes it works fine, you can still see what people are doing
06:54 GuShH_Lap I used some 900 usd sony ip cameras the other day
06:54 GuShH_Lap amazing.
06:54 GuShH_Lap I was able to zoom onto labels at the shop and read them, full auto focus.
06:54 GuShH_Lap they were domes
06:55 GuShH_Lap and they were the "cheap" ones from the series
06:55 GuShH_Lap imagine what the expensive ones can do!
06:55 theBear you're a smart guy, you should workout how to ryo video TRANSFORMER and tell me :)
06:55 theBear heh, i don't follow that stuff much, but sony aren't exactly cheap or mid range price/quality wise :)
06:55 GuShH_Lap sadly I lost the IP addresses and I can't find them on the disc images (a 200GB disc failed on me last week)
06:56 theBear bummer
06:56 GuShH_Lap I got most of the data out, I just can't search the image files....
06:56 GuShH_Lap no such option in norton ghost it seems
06:57 theBear if/when you ever do have access to fancy cams like that, and if you got a android something, tinycam viewer is a damned fine cam frontend... has multicam, zoom/pan etc etc all in the free version
06:58 GuShH_Lap you know the world has gone to shit when the local news channel shows "tweets from famous people" at 9AM
06:58 ShH_Lap s
06:58 GuShH_Lap even the news programs have become reality crap.
06:58 GuShH_Lap well, the other kind of reality, the fake reality. the unreality. you know what I mean!
06:58 theBear err, tinycam monitor
06:59 theBear heh, yeah, news aint news anymore... maybe on the govt-sponsored non profit channel, but nowhere else
07:00 GuShH_Lap our gov news is on a gov channel and it's all lies.
07:00 GuShH_Lap when poop hits the fan they show an old documentary or something within the lines
07:00 theBear oh yeah, your govt doesn't even pretend to be impartial like ours :)
07:00 theBear tho the channel i speak of is also prettymuch independant, a lot like bbc
07:23 GuShH_Lap theBear: problem is the house is in the middle of the lot, so you have a lot of corners to cover
07:24 GuShH_Lap that implies lots of wiring, lots of cameras. even with smart placement
07:24 Tom_itx dig a moat
07:24 GuShH_Lap biggest problem is, how much do you have to spend to digitize all those cameras?
07:24 GuShH_Lap sorry?
07:25 theBear i dunno, i never bought a capture card, one i use at the moment i had to write a card config/custom init/input switch for in the bt878 driver, but it has 4 full rate capture chips and 16 input magic multiplexer chipset, i like it
07:25 GuShH_Lap Tom_itx: if I don't fix a broken pipe, the moat may just appear naturally eventually
07:25 Tom_itx problems solved
07:25 Tom_itx now just get busy on the draw bridge
07:26 GuShH_Lap moats are actually smelly, fyi.
07:26 GuShH_Lap Tom_itx: you see, even if I had a moat I'd want cameras to see people try and get past it
07:26 GuShH_Lap it would be way better than TV
07:27 GuShH_Lap theBear: me neither...
07:27 GuShH_Lap I'd want 8 inputs
07:27 GuShH_Lap doesn't have to be over 10fps PAL res.
07:27 theBear i been given a few over the years, is what i'm implying
07:28 GuShH_Lap bah! quit bragging about your free security system :p
07:28 theBear apparently there are a bunch of good-os compatible ones available for a decent price, including 8 channel/chip ones... i can ask in the other channel if yer want a link
07:28 theBear hehe
07:29 GuShH_Lap a new 8 channel "cheapie" goes for 100 usd here :(
07:29 GuShH_Lap the 4 chan one isn't much cheaper in fact it's the same card minus the addon
07:31 GuShH_Lap It's still cheaper than buying an actual DVR of course
07:31 theBear yeah, but you can amazon/dx can't yer ?
07:31 GuShH_Lap dx, but this kind of stuff gets stuck on customs usually
07:32 GuShH_Lap unless you are really lucky, which I'm not.
07:32 theBear and you can probly do 10fps alternated on a single chip for 2 inputs if it got switching, but usually various auto-blah will make it unusuable alternated straight up, and 10frame THEN 10frame every second is kinda shitty
07:33 GuShH_Lap this one does 100 or 120fps, but that's the total...
07:33 GuShH_Lap divided by N amount of cameras I would imagine
07:34 GuShH_Lap not even 15fps worst case
07:34 theBear generally that means 25 or 30fps * capture chips
07:34 GuShH_Lap for 8 inputs
07:34 GuShH_Lap but is that progressive?
07:34 ShH_Lap fr
07:34 GuShH_Lap theBear: it's not like you'd store at 30FPS even if you could though
07:34 theBear that's traditional, these cards are all based on video/tv capture chips...
07:35 theBear some of the guys in the security channel do, seems a bit silly to me, i run most cams around 6-8fps at the moment (p3-1000 with 3 cams fulltime) ... more than enough for most security purposes
07:35 theBear well, enough anyway :)
07:36 GuShH_Lap hmmm
07:36 GuShH_Lap for viewing purposes the more the better
07:36 GuShH_Lap but storage wise at 30fps you run out of space pretty fast
07:36 GuShH_Lap unless you've got 3TB dedicated to the camera....
07:36 GuShH_Lap most DVRs I've seen come with 500GB
07:37 theBear i tend to go for numbers nicely divisible, ie. 6 or 8 i can have my lowrate snapshot.jpg saved every 3 or 4 frames, and my mobile viewer can do 1fps 'idle' and up to 2 or 3 or 4fps during events (detected motion)
07:37 Tom_itx motion triggered
07:37 theBear yeah, only recording events helps a lot, but it still adds up
07:37 GuShH_Lap Tom_itx: wind
07:37 GuShH_Lap "define zones" = dead useless system
07:37 theBear even when i used to do maybe 4f/minute timelapse that adds up QUICK
07:37 GuShH_Lap it's not a concrete jungle, it's an actual jungle... or the woods, of sorts
07:38 Tom_itx like the ones hunters use
07:38 GuShH_Lap yes you get 10000 pictures, 10 with deers, 1000 with bugs the rest just wind
07:38 theBear GuShH_Lap, with a decent software/system that isn't such a problem, you can usually define auto-mask rates, noise amounts, number of frames vs amount of change etc etc
07:38 GuShH_Lap theBear: it ends up masking so much it's probably never going to trigger on a real event
07:38 theBear and 'light switch' settings are good for avoiding things lke sun/auto-bright false triggers
07:39 GuShH_Lap when you mask out zones it means you've installed the camera in the wrong place to begin with
07:39 GuShH_Lap and you are just wasting sensor space
07:39 theBear no... just, no :) trust me, i played with this stuff a lot, and i haven't masked for years, tho if i ever glance say, the street or something JUST in the corner over a fence, AND it's not in line with a real-detection area, i might mask it
07:39 GuShH_Lap I wonder if a high resolution 360 dome up the roof wouldn't be cheaper than 8 or more cameras heh
07:40 theBear i know that a small mirror say, 'in the sky' or a fisheye is a lot better/cheaper than dual cams for me
07:40 GuShH_Lap (notice, it's not just the cost of the cameras, also the wiring and other extras)
07:40 GuShH_Lap such as lenses, connectors, psus and whatnot
07:41 GuShH_Lap I've got a p3 doing nothing... and two athlons xp doing nothing... one of them could serve as an OK DVR
07:41 GuShH_Lap even though none of them does sse2 or better....
07:41 GuShH_Lap theBear: most of these cheap cards seem to perform most tasks on software :(
07:41 theBear between my xp1800+ WITH throttling and my p3-1000, i find the p3 is MUCH more affordable power wise
07:42 GuShH_Lap it's a 750MHz old piece of junk
07:42 theBear even doing detection on 3 cams and no throttling the p3 uses less power than the throttled/idle xp
07:42 GuShH_Lap the other is 1.7-8 or so the other 1.9 and overclocked at 2.3 heh
07:42 GuShH_Lap they could be used to heat up the room on a pinch....
07:42 theBear one of these days i'll get around to recapping the other xp board, that can do voltage throttling too, i think that'll then win for my server/24-7/security machine
07:43 GuShH_Lap :p
07:45 GuShH_Lap http://www.abdvr.com/kmc.htm
07:45 theBear speaking of which, after THIS cigarette, i WILL stick that new psu in this here box been taking my underdesk room for way too long... if i can get it running right i can replace this stupid p4-ht in my bedroom and maybe not be stupid-hot by the end of summer
07:45 GuShH_Lap at least it's got 8 chipsets
07:46 theBear wow ! kodicom 4400 is 98% identical to my card ! my card 'doesn't exist' tho :)
07:47 theBear i say this from memory, not that page
07:47 theBear i thought they would be long-dead
07:47 theBear for reference, those specs are for their software/other software, with a real os/driver you can do whatever a bt878 can do
07:48 GuShH_Lap hmm
07:48 theBear not that you can go much higher, but as far as pal stretches, and inbetween res's if you want
07:50 theBear with that model/ if you solder a connector you can monitor multiplexed passthru (as in straight thru anyway switcher ic) at full/real quality on a compatible monitor, regardless of recording mode.. and in theory you could switch that at any arbitrary rate/sequence between inputs
08:03 GuShH_Lap theBear: hmm yeah I can see a header there but no documentation
18:30 Tom_itx CSS555
18:30 Tom_itx programmable 555 timer
18:31 Tom_itx http://www.customsiliconsolutions.com/downloads/Revised%20Standard%20products/CSS555_App_Note1_Serial_Interface.pdf
19:33 rue_house thats a joke right?
19:33 Tom_itx no joke
19:33 Tom_itx came to me from jameco
19:33 MrTrick During delivery and acceptance of my project; "What would happen if I stuck my finger in it while it was running?"
19:33 Tom_itx it would trigger a response
19:34 rue_house the system would have a reaction to you action
19:34 MrTrick ^_^
19:37 MrTrick "You'd get an owie."
19:40 Tom_itx rue_house, you don't have to change components on it to change frequency
19:40 Tom_itx you just reprogram it
19:40 rue_house MrTrick, :)
19:40 rue_house "me stitching your finger back on is gonna hurt more than the process you went thru to get it cut off.."
19:42 Tom_itx rue is this valid c? if(condition,{dothis},{dothat}); ?
19:42 Tom_itx i think it is
19:42 MrTrick Tom_itx: no.
19:43 MrTrick if (condition) { dothis... } else { dothat... }
19:43 Tom_itx i've seen it written as an immediate if though
19:43 MrTrick Not like that.
19:43 Tom_itx well the syntax is what i'm looking for
19:44 MrTrick You can possibly have a 'condition' that has side-effects.
19:44 Tom_itx i know about if else etc
19:44 MrTrick for instance, if you need to do an assignment AND an if check;
19:45 MrTrick if ( q = myfunc() ) { print("Assigns q to the result of myfunc(), and prints this message if q isn't 0"); }
19:45 MrTrick The form can be useful, but it's really easy to confuse assignment with equality.
19:46 Tom_itx x == 0 ? true:false
19:46 Tom_itx maybe that's it
19:46 MrTrick The ternary form. Sure, that's possible, though it's not quite the same.
19:46 MrTrick because that's not so much 'dothis/dothat' as it is assignment.
19:46 Tom_itx <bool condition> ? <true value> : <false value>;
19:46 MrTrick x_is_0 = (x==0) ? true : false;
19:48 Tom_itx could <bool condition> be a true false return from a function?
19:48 MrTrick yep.
19:48 Tom_itx x == is_this_an_apple() ? yes : no
19:49 MrTrick wait, = not ==
19:49 Tom_itx yeah
19:49 Tom_itx there it would be =
19:49 MrTrick It's a really old mistake in my opinion... '=' is a bad choice for "assign right side to left side."
19:50 MrTrick At least you're not writing php or javascript... they also have ===!
19:57 RifRaf MrTrick you asked about the micro servos, they are just for the gripper, using 3 different servo types now
19:57 MrTrick ah okay, cool.
19:57 RifRaf and making some mini gimbles that i need the other 3.6g servos for
19:57 RifRaf the base 3 are standard ones, and will be changed to mg996 when they arrive
19:57 MrTrick I delivered the robot arm I built yesterday to the client, so hooray - I'm getting paid. ^_^
19:58 RifRaf wow cool, did you show any images of it?
20:04 rue_house yea lets see!
20:04 rue_house I need to be inspired that more than just me and rif are building robots
20:06 MrTrick hmm
20:06 MrTrick http://i.imgur.com/PhfKr.jpg
20:06 rue_house I have a new one I'm playing with, and I want to make it all back drivable, but I'm not totally into making gearboxes for it
20:07 rue_house ah yes
20:07 MrTrick and http://i.imgur.com/SmQnzOe.jpg
20:08 rue_house :) kinematics are fun eh?
20:08 MrTrick Actually, simple.
20:08 rue_house what servo controller were you using?
20:09 MrTrick And I figured out - I think inverse kinematics for any robot arm is easy, *as long as* there's only one solution.
20:09 rue_house :)
20:10 MrTrick For this one, it's just calculating the two arm angles. Any junior highschool student of sufficient smartness could do it.
20:10 rue_house http://eds.dyndns.org/~ircjunk/robots/arm6/p1040198.jpg
20:10 rue_house I need to get better at taking pics of the overall robot after I make progress
20:10 MrTrick Parallelogram! :-P
20:11 rue_house its a larger version of
20:11 rue_house http://eds.dyndns.org/~ircjunk/robots/arm4/p1010986.jpg
20:13 MrTrick cool.
20:13 rue_house steppers suck
20:14 rue_house it might outpage a snail, any faster and it skips steps
20:14 Tom_itx they can do quite nicely though
20:15 rue_house http://www.youtube.com/watch?v=Ad75LMrrE_U&list=UUPqhe-f22nx8XkLW-CysxQw&index=33
20:15 rue_house "THATS ALL SHES GOT CAP'N I CANT GETTER TO GO ANY FASTER!"
20:16 Tom_itx i think i saw that one
20:16 rue_house http://www.youtube.com/watch?v=QZXRw61C1og&list=UUPqhe-f22nx8XkLW-CysxQw
20:16 rue_house that one is the linear interpolator at work
20:17 Tom_itx you stop postin stuff i might get this icecream et then i can probe the pins again
20:17 rue_house no wtf, why does youtube try to chain all the damned videos now
20:18 Tom_itx yeah i noticed that yesterday when you posted
20:18 rue_house http://www.youtube.com/watch?v=gJObCH2trDI
20:18 rue_house thats the linear interpolator
20:19 Tom_itx why are we all on 7seg all the sudden?
20:20 rue_house even the planets align *sometimes*
20:20 Tom_itx bcd would only need 4 pins
20:21 MrTrick rue_house: what's the stepper gearing like? Do you have specs on their torque, etc?
20:23 rue_house they are charting motors, the gearing is about 30:1
20:24 MrTrick ah okay. I bought a couple of these for the next arm; http://www.phidgets.com/products.php?category=23&product_id=3318_1
20:24 rue_house void SimotaniouslyLinearlyInterpolateMultiAxis(axies_t * this) {
20:24 rue_house that was the controlling function in that video you saw
20:24 rue_house it can do linear interpolation of up to 65536 axies
20:25 rue_house which I know is a stupid limit, but I'v not exceeded it yet on any of my robots
20:25 rue_house MrTrick, learn to do DC servos, get away from steppers
20:27 MrTrick rue_house: I'm moving away from *RC* servos... how does one control a proper DC servo?
20:27 Triffid_Hunter MrTrick: 3 nested PID loops
20:27 rue_house you put a position sensor on your axis
20:27 rue_house gear the mtoor
20:27 Triffid_Hunter MrTrick: the innermost, tightest one controls current. the next one out controls velocity, and the third, slowest one controls position
20:27 rue_house and apply loop controller code
20:28 MrTrick The thing is, I've found that for my application *synchonisation* is critical.
20:28 rue_house I'm doing good with just proportionate code
20:28 MrTrick And none of the steppers have to overcome more than inertia.
20:28 rue_house thats why I wrote void SimotaniouslyLinearlyInterpolateMultiAxis(axies_t * this) {
20:28 Triffid_Hunter MrTrick: for sync you need to start looking into stuff like grbl
20:28 MrTrick heh
20:28 Triffid_Hunter MrTrick: then set your DC servo controllers up to receive step/dir pulses
20:28 MrTrick Triffid_Hunter: I've got a grblShield on its way. ^_^
20:29 rue_house it can be used with any kinda servo
20:29 Triffid_Hunter MrTrick: fwiw reprap firmwares have the sync thing quite well sorted
20:29 rue_house as it uses callbacks to issue the servo position updates
20:29 MrTrick I like the step/dir pulse -> servo idea.
20:29 Triffid_Hunter MrTrick: our needs for good sync are higher even than those of subtractive cutting since the melt flowing from the nozzle can't start and stop
20:29 MrTrick What about geared servo motors that aren't crazy expensive?
20:30 rue_house MrTrick,
20:30 Triffid_Hunter MrTrick: http://www.2engineers.com/
20:30 rue_house http://eds.dyndns.org/~ircjunk/tutorials/mech/gearbox/gearbox.html
20:31 MrTrick Triffid_Hunter: those are steppers...
20:32 MrTrick and I'm *not* making my own gearboxes. :-P Backlash is an issue.
20:32 Triffid_Hunter MrTrick: you can make a servo with steppers
20:32 Triffid_Hunter MrTrick: lots of dc brushed gearhead motors sold in robotics shops for drivetrain
20:33 Triffid_Hunter may also want to look into BLDC, they're a bit trickier to drive but have better power to weight ratio and lower EMR because you're not dealing with brushes
20:33 MrTrick Okay, let me clarify my requirement, then. Is there a product that consists of a servo controller and geared motor with encoder, that works with grbl?
20:33 Triffid_Hunter MrTrick: if there is I'm not currently aware of it
20:34 Triffid_Hunter MrTrick: what I do know is that it's fairly easy to find DC gearhead motors with encoders, then couple with something like github.com/triffid/ESC which can be coded for step/dir and an encoder instead of servo input easily enough
20:34 MrTrick I understand what you're recommending. If this were for a hacky project, I'd be willing to try all kinds of interesting combinations. This unfortunately needs something that will work, hopefully first time.
20:35 Tom_itx http://www.excitron.com/
20:35 Triffid_Hunter MrTrick: ah, only commercially available off-the-shelf stuff I've seen for this is $$$
20:35 MrTrick yeah, fair enough.
20:35 Triffid_Hunter like the maxxon stuff, cost you up to several $k
20:36 Triffid_Hunter so I generally don't even consider it
20:36 MrTrick yeah. Maybe next time, once I've gotten familiar with grbl.
20:38 Triffid_Hunter MrTrick: if you want to know how the synchronisation works, see stuff like bresenham's line algorithm or http://www.eetimes.com/General/PrintView/4026992
20:39 MrTrick yes, bresenham is nifty. ^_^ For my RC servo controlled arm, I just calculated the number of intermediate steps I'd need between adjacent points (From max speed / update rate) and linearly interpolated from A->B.
20:42 Triffid_Hunter problem with bresenham is the jitter on non-master axes.. it's generally ok but we're starting to look into other stuff like the pramod ranade algorithm in which we always run the step interrupt at top speed and just choose when to step each axis
20:42 Triffid_Hunter instead of bresenham, which steps all applicable axes when the master axis steps which gives high jitter for the slaved axis when you're moving X2 Y3 or similar
20:43 MrTrick What about independent axis controllers?
20:43 MrTrick (theoretical discussion - no intention of using it for my next project)
20:44 MrTrick eg, if each axis controller understood some drawing primitives, and the master controller broke the operations down into per-axis primitives and dispatched them.
20:45 MrTrick I guess it doesn't work when your machine's axes aren't independent.
20:46 Triffid_Hunter MrTrick: sure, that works. then they each run bresenham locally, assuming that the other controllers are also running it at the same speed
20:46 Triffid_Hunter MrTrick: the trick then is you need a signal to start them all at the same moment
20:46 rue_house hahah faling asleep in my chir
20:46 rue_house a
20:46 Triffid_Hunter and keep them synchronised, since the clocks will drift in time
20:47 MrTrick I just wonder how generally applicable it could be. For a cartesian configuration, a linear operation (eg G0 or G1) breaks down into linear primitives. For a delta configuration... what do the primitives for a linear operation look like?
20:48 Tom_itx rue_house
20:48 Tom_itx why not just define hex values for your array?
20:48 Triffid_Hunter MrTrick: log curves
20:48 Triffid_Hunter MrTrick: in reprap-land we get around that by converting them into a series of short linear moves
20:49 MrTrick ah, cheating. :-) Excellent. (Don't worry, I plan to do the same for getting grbl to control my scara arm)
22:50 rue_house Tom_itx, whats the value for a fancy 7?
22:50 rue_house quick now
22:50 rue_house wait what if A is on bit 2 instead of 0
23:45 RifRaf succesfully cut cylinders 0.7mm wide by 3mm high
23:48 rue_house for?
23:50 rue_house am I still transmitting here?
23:50 rue_house !time
23:50 tobbor My watch says its 09:43PM Tue Feb 05 2013
23:51 rue_house yes, seems I am