#robotics Logs

Mar 15 2014

05:27 aemquo Hello
11:06 rue_mohr2 hi
12:02 rue_mohr2 "AAAH NOT IN MY EYE! your not a verry good doctor!" "sorry, gee, it would be helpfull if I were a doctor and you weren't an alien"
12:51 rue_mohr2 "by 'try to eat something' I didn not mean my hand, now off to the kitchen with you!"
13:00 GuShH_ rue_mohr2: I found a nice ornament for my garden http://gushh.net/tmp/p15-03-14_13.02[1].jpg part of a flak battery from our navy
13:00 GuShH_ the shield is surprisingly less than an inch thick!
13:01 GuShH_ mixture of a play ground and a battle field... interesting park http://gushh.net/tmp/p15-03-14_13.02.jpg
13:02 GuShH_ that's near a local war veteran center, next to the memorial park
13:04 GuShH_ http://gushh.net/tmp/p15-03-14_13.01[1].jpg the posts, nothing moves... I tried the elevation which is on the right side, stuck.
13:04 GuShH_ could it be part of the decomissioning? ie. welding all moving parts, or it's just rust but I didn't see any rust
13:06 MrCurious children love artilery....
13:08 GuShH_ MrCurious: they do?
13:08 GuShH_ I didn't have any of this stuff while growing up :(
13:08 GuShH_ I wanna go play there! when nobody is watching.
13:09 GuShH_ Actually I want to see if they need anything at the center
13:15 MrCurious you ever make your own fireworks GuShH_
13:15 MrCurious did it end like this? http://www.youtube.com/watch?v=W5waof0iWE8
13:17 GuShH_ I used to make my own black powder and everything
13:17 GuShH_ never an accident
13:17 GuShH_ AS A CHILD
13:18 GuShH_ I was a pyro kid
13:18 GuShH_ but never caused damage.
13:18 MrCurious i think that is a childhood requirement
13:18 MrCurious did you ever get a result like that one?
13:18 robopal MrCurious, not really, I mean, we all played with matches at some level, but he went a big farther with the black powder ;p
13:19 GuShH_ I had help from my brother, for the salt peter.
13:19 MrCurious :D
13:38 mehtanisarg3 What's up
13:47 MrCurious i guess our response time is up...
13:57 MrCurious http://digg.com/video/making-water-flow-uphill
13:57 MrCurious ok thats rather cool
15:10 peepsalot what does it mean if a hobby servo is labeled "digital"
15:11 GargantuaSauce the control system inside uses a microcontroller instead of an analog amplifier/filter
15:12 GargantuaSauce it is not a guarantee that it performs well though
15:12 peepsalot ok
15:19 GuShH_ GargantuaSauce: you reckon feedback is the same for the closed loop portion of the digital servo?
15:19 GargantuaSauce they all use pots
15:20 ShH_ overdosed with bbq and idly m
15:20 GargantuaSauce only super fancy expensive ones use encoders
15:20 GuShH_ why aren't you fancy enough then
15:21 ShH_ opens his bookm
15:21 GargantuaSauce because i don't have stupid amounts of money
15:21 GuShH_ you should become friends with donald trump
15:21 GargantuaSauce i do want to build some nice ones but am still procrastinating on building up a pcb design+etching process
15:22 GuShH_ MrCurious: got any more poorly edited fake videos to share?
15:22 GuShH_ I'll show you what an explosion looks like, just head over here.
15:22 peepsalot yeah i kinda wanna play with one of these http://www.trossenrobotics.com/dynamixel-mx-28-robot-actuator.aspx but its a bit pricy
15:23 GuShH_ GargantuaSauce: careful, rue might point you to the nothing bot
15:23 peepsalot was thinking about using it in continuous mode as a 3d printer extruder
15:23 GargantuaSauce i wouldn't mind working on rue's stuff but i'd probably have to redo all his software!
15:24 GargantuaSauce peepsalot: wtf
15:24 GargantuaSauce why would you use that on an extruder
15:24 GuShH_ because, reprappers
15:24 GargantuaSauce whats wrong with a $9 stepper
15:24 GuShH_ sadly a $9 stepper there, is a $60 stepper here :(
15:24 peepsalot more compact/lightweight built in gearbox high torque etc
15:25 GuShH_ bah better go do something.
15:25 GuShH_ I got some nice caulk for the swimming pool, let's fix it
15:26 GuShH_ not the most expensive one mind you, the one in between prices. am I cheap? you bet.
15:26 GuShH_ surely at some point you begin to pay for snake oil?
15:27 GargantuaSauce i never took you for a connoiseur of high-class caulk
15:27 peepsalot are there other cheaper servo motors that can do continuous movement with any kind of positional feedback?
15:28 GargantuaSauce i havent seen any <$100
15:28 GargantuaSauce and seriously, use a stepper and torque converter for the extruder
15:29 GargantuaSauce they can be not much less compact than that servo
15:29 peepsalot torque converter? got an example?
15:29 peepsalot most geared steppers are fairly expensive too
15:29 GargantuaSauce one of the 8593 designs that use two 3d printed gears
15:30 GargantuaSauce direct-drive also works if you use a slightly bigger steppe
15:30 GargantuaSauce if you want to minimize weight on the hot end carriage, use a bowden tube
15:35 peepsalot yeah bowden is probably the way to go, just seems like it introduces a lot of "backlash" with the filament compressing in the tube
15:37 GargantuaSauce a bit yes
15:37 GargantuaSauce pretty much every slicer has provisions to reduce that though
15:37 peepsalot what is 8593?
15:37 GargantuaSauce a big number i keyboard mashed
15:38 GargantuaSauce seriously go on thingiverse and look for extruders
15:38 peepsalot oh, ahha, i thought that was some specific model of something
15:38 GargantuaSauce there are a lot of options
15:38 peepsalot yeah i know, just thought a servo seemed interesting
15:39 peepsalot i've built a prusa 1st gen, then upgraded every part on it to 2nd gen, then melted it in my car on accident
15:39 peepsalot i'm planning on rebuilding as a delta bot this time
18:43 GuShH_ peepsalot: #plasticoozingfetish
18:44 GuShH_ #spaghettiextrudingnerds
18:45 GuShH_ got the ring replaced for the right size one, installed... all fine. damn these guys at the store are blind, they even argued "these two rings are the same size" when they were clearly not.
18:46 GuShH_ a difference of ~0.02mm over the actual size means it won't fit whatsoever on a new / as new cylinder, given 0.05mm is the clearance between piston and cylinder....
18:47 Tom_itx they are to the same!
18:47 GuShH_ no! I held them vertical and one was clearly bigger, they just didn't know how to visually compare rings.
18:47 GuShH_ but I do wonder why it only got one ring, when most chainsaw pistons are double ring
18:47 Tom_itx cost
18:48 GuShH_ it's a nice store, they'll let me swap parts if they gave me the wrong size, no questions asked... I did learn my lesson though, don't trust clerks... seems I forget that quite often.
18:48 GuShH_ Tom_itx: but some of these other chainsaws have double rings! and they come from the same factory in china!
18:49 GuShH_ there's no point in replacing the piston, it's got no marks
18:49 Tom_itx is it a needle crank?
18:49 GuShH_ 2 years of using castrol actevo, no carbon deposits whatsoever.
18:50 GuShH_ Tom_itx: needle bearings on both ends of the conrod
18:51 GuShH_ it has ball bearings on the crankshaft
18:51 GuShH_ couldn't get replacement seals for the crankshaft... but I noticed they were slightly pushed out, so I hammered the crap out of them using a big socket, they went in further. I actually know where to get new ones, it's just a long drive...
18:52 GuShH_ and as with any shop around here they want you to bring samples
18:52 GuShH_ because they don't know what numbers are.
18:52 GuShH_ "what? we just compare what you bring with what we have, there are no numbers!"
18:53 GuShH_ how do you remove the seals without destroying them? I thought about using compressed air to pop them out, but I would have to seal the cylinder ports and lock the piston
18:53 GuShH_ not sure 120PSI would do it
18:57 GuShH_ http://bbs.homeshopmachinist.net/threads/38026-Electropolishing-and-cleaning-stainless-steel-and-aluminum
18:57 GuShH_ interesting
18:58 GuShH_ rue_mohr2: feeling better??
20:07 rue_mohr2 no
20:25 rue_mohr2 "throat medicine, sleep, some fresh air, entertainment, vitimins,, every entry carefully timed and tracked!" "but did you remember to feed him" "of course he last ate at"...(flip, flip flip, flip flip flip)....."we forgot to feed him..."
20:31 rue_mohr2 "the foods been warming up on the stove for about 15 mins now" "did you use the high setting again?" "...y e s....damn..."
20:32 rue_mohr2 "how did you know?" "hear that loud beeping noise?"
20:42 GargantuaSauce http://www.youtube.com/watch?v=ylJovLCM3DY
20:43 GargantuaSauce this is so damn obvious, wish i'd thought of it
20:43 GargantuaSauce probably not too reliable but soooo simple
20:45 Fiesta i dunno GargantuaSauce, is that within spec?
20:45 GargantuaSauce within spec of what
20:46 Fiesta of all of the things he's using which havn't been used for that before
20:46 GargantuaSauce it's just a voltage divider i think
20:46 GargantuaSauce nothing special going on
20:47 GargantuaSauce resistance is probably in the tens of kohms
20:47 GargantuaSauce lemme see..
20:48 Fiesta i'm being facetious
20:49 rue_mohr2 I hope your aware that conductive foam loses a little thickness every time its squished
20:50 GargantuaSauce well all i've learned so far is that a lot of the foam ICs i've bought from china came in is not actually conductive x_x
20:50 GargantuaSauce obviously this isn't going to result in anything approaching a precision device rue
20:51 rue_mohr2 I think I tried it once and gave up on durabilty problems
20:52 GargantuaSauce stuff from mouser definitely is though, about 2kohm/cm
20:53 GargantuaSauce not linear at all but who gives a shit
20:53 GargantuaSauce obviously the usefulness of this is going to be limited but i am going to mess with it anyway
20:58 GargantuaSauce might be a very good first attempt at a pressure sensor for a gripper for instance
20:59 GargantuaSauce will destroy itself after a few uses but still a nicer starting point than paying for "real" touch sensors
21:01 GuShH_ not to be confused with touch censors
21:02 GuShH_ that conductive foam is not meant to be compressed and I don't get why you'd want to print that instead of turning it on a lathe!
21:03 GargantuaSauce uh because you don't want the whole thing to be conductive?
21:03 GuShH_ uh, you can turn plastics as well.
21:03 GargantuaSauce lies
21:03 GuShH_ I turn acetal all the time
21:03 GuShH_ what are you on
21:03 GargantuaSauce a chair
21:03 GuShH_ there are lots of engineering plastics!
21:03 GuShH_ LOTS
21:03 GuShH_ delrin turns like butter
21:04 GuShH_ as long as it doesn't have any loads such as graphite... it's not going to be conductive
21:04 GuShH_ hmm nothing worth watching on tv... ever.
21:05 GuShH_ chainsaw started after about 20 pulls, it was flooded with oil from the assembly, works ok but I think the check valve from the gas tank is acting up... now I need to perform the break-in process again :(
21:06 GargantuaSauce you don't get on hackaday by turning delrin on a lathe
21:06 GargantuaSauce therefore it is a process without merit
21:06 GuShH_ Don't fucking challenge me on that
21:06 GargantuaSauce :D
21:06 ShH_ fr
21:07 GuShH_ Should I... No.. I already proved someone wrong about HaD. Why do it twice
21:07 GargantuaSauce generally when i bring up that site i am being facetious
21:07 GargantuaSauce you don't have to prove shit
21:08 Jak_o_Shadows HaD has some things it likes
21:08 GuShH_ I did that on ##electronics once, when I said any idiot could get featured on that site
21:10 GuShH_ Jak_o_Shadows: I guess, I don't browse the site anymore
21:10 GuShH_ since they went for "more instead of quality"
21:10 GuShH_ But glad to hear it's still around
21:11 GuShH_ I really want to test electro-polishing for aluminum and stainless
21:11 GuShH_ any idea if phosphoric acid can be swapped out for some other acid?
21:12 Jak_o_Shadows Why do so many people have a hard-on about 3D printed parts that could easily be made anyway?
21:12 Jak_o_Shadows oooh, there's no non-3D printed parts: However, tolerances suck
21:12 GuShH_ Because they can't make them otherwise
21:13 GuShH_ they spend all their money on plastic spaghetti instead of real tools
21:14 GuShH_ it's actually simpler to obtain and operate a lathe than it is to build or buy and setup a reprap, given most people can't even model a friggin cylinder, let alone export one.
21:14 GuShH_ plus all the calibration involved...
21:14 GuShH_ and all the babying
21:14 GuShH_ of course they're different things
21:14 GuShH_ so meh. in his case it allowed him to _prototype_ an idea with what he had
21:15 Jak_o_Shadows 3D printed parts probably have a load of creep, have significantly different yield strength in different directions, and in general, isn't too strong anyway.
21:15 GargantuaSauce yeah i am still on the fence about its usefulness
21:15 GuShH_ assuming you managed to print it all the way
21:15 GuShH_ without it pooping itself.
21:15 Jak_o_Shadows The signifcantly different yield strength makes things slightly more complicated. Not that I imagine that too many people bother learning how to actually design stuff.
21:16 GuShH_ those "awesome" prints you see are the result of countless hours babying the machine nonstop day and night.
21:16 GargantuaSauce yeah
21:16 GargantuaSauce i had a few good prints
21:16 GargantuaSauce and then skeinforge stopped working
21:16 GuShH_ then you fart, and it's off calibration.
21:16 GargantuaSauce and NEVER had the same results with slic3r
21:17 Jak_o_Shadows Holy hell, the wikipedia page for stress is horrible. It would scare off anyone.
21:17 GuShH_ hrmm I can source phosphoric acid but it's a long drive...
21:19 GuShH_ to the #chemistry nanana
21:20 Jak_o_Shadows Surely somebody has done some work at quantifying 3D printing material properties
21:20 GargantuaSauce well the thing is, it's not the material
21:20 GargantuaSauce it's the way it's deposited
21:20 GargantuaSauce which is exceedingly complicated
21:21 GargantuaSauce since the toolpath is determined by software, and then there are mechanical inaccuracies
21:21 Jak_o_Shadows Even just a few test prints, with photos so you can try to compare print quality, and then tests
21:21 GuShH_ are there many water cooled hotends, at all?
21:21 GargantuaSauce and adhesion depending on the specific temperature, etc
21:21 GuShH_ many/any, except I've seen a modified e3d
21:21 GuShH_ with a water jacket
21:21 GargantuaSauce i've seen it done, it's uncommon though
21:21 GuShH_ gimmick?
21:21 GargantuaSauce well not really necessary
21:22 GargantuaSauce a little heatsink+fan does the trick just fine
21:22 GargantuaSauce much cheaper and less failure prone
21:22 GuShH_ what if you wanted more power, assuming you could print faster without lowering your overall print quality
21:23 GuShH_ surely you would have to scale things up, or go with fluid coolant
21:23 GuShH_ I wonder if weight isn't a massive issue
21:23 GargantuaSauce weight is certainly a bit of an issue, depending on the actuation of cour
21:23 GargantuaSauce se
21:23 Jak_o_Shadows Possibly a heatsink with fins would work better
21:24 GargantuaSauce better axes would be able to handle more mass and acceleration
21:24 GuShH_ I still think a general purpose cnc 3-4 axis bed is a better investment, and could be made to print plastic too.
21:24 GargantuaSauce i am inclined to agree, though it would likely be slower
21:25 ShH_ sh
21:25 GargantuaSauce i definitely want to build a cnc mill/router
21:25 GuShH_ yeah
21:25 GargantuaSauce or maybe just buy a chinese one i dunno
21:25 GargantuaSauce ballscrews are so fucking expensive
21:25 GuShH_ what an idiot, I forgot to ask about t-slot alu profiles at the store.. I asked for billets and forgot about the rest.
21:26 GargantuaSauce http://www.youtube.com/watch?v=nebJ59TcYlQ i've posted this a bajillion times but need to fawn over it once more
21:26 GargantuaSauce this is probably what i'd do
21:27 GuShH_ I want alu milling, laser cutting, plotting maybe 3d printing and... if I'm nuts enough, I could probably turn it into a small plasma cutter, assuming I use steel for the structure and separate "beds"
21:27 GuShH_ it just has to be rigid enough for the metal working, the rest is irrelevant.
21:28 GuShH_ I can see those stepper drivers and steppers being more useful in such a machine.
21:28 GuShH_ but of course we're talking a bigger scale than your average reprap
21:28 GargantuaSauce ya 20x20x15cm is a bit small
21:29 GuShH_ 3Nm at least
21:29 GuShH_ nema 24
21:29 GuShH_ on the small scale..
21:32 GuShH_ I'm leaning toward steel for just about everything
21:32 GuShH_ instead of aluminum
21:32 GuShH_ perhaps at the cost of speed
21:34 GargantuaSauce how come?
21:34 GuShH_ higher mass
21:34 GuShH_ heavier.
21:35 GargantuaSauce heh i usually think of higher density as worse
21:35 GuShH_ if we don't compensate, using the same motors... something has to give, the drive ratio.
21:35 GargantuaSauce i mean why steel over aluminium, not why does it cost speed
21:36 GuShH_ welding alu is not cheap nor simple
21:36 GargantuaSauce ah yeah welding
21:36 GuShH_ and I don't want to have fastened portions like a meccano.
21:36 GuShH_ plus steel is cheaper
21:36 GuShH_ and I'm cheep
21:37 GargantuaSauce be nice if argon grew on trees
21:37 GuShH_ foam cutters seem to sell ok-ish around here
21:37 GuShH_ only a few people are making them
21:37 GuShH_ be nice if proper ac-dc tig welders were cheap.
21:37 GuShH_ the gas is the least expensive portion
21:37 GuShH_ compared to the welder, for me
21:38 GuShH_ I already have a tank, it just needs to be certified again
21:38 GuShH_ then refills are rather cheap
21:41 GuShH_ GargantuaSauce: in essence, I'm too poor for a proper alu welding setup.
21:41 GuShH_ and it takes more than argon and a machine to get usable results!
21:43 GuShH_ I'm not sure I can weld a precise, straight bed with steel though. it would need some adjustment built in
21:43 MrCurious i wish i could weld aluminum
21:43 GuShH_ MrCurious: you can, if you invest first.
21:43 MrCurious heh
21:57 GuShH_ MrCurious: thing is a cheapie ac-dc welder won't cut it for serious work (anything other than tack welding aluminum)
21:57 GuShH_ that's why it's not cheap to get started properly
21:57 MrCurious you need special gas and that sand stuff
21:58 Jak_o_Shadows http://en.wikipedia.org/wiki/Stress_%28mechanics%29 is slightly less horrible now, but still nasty
21:58 MrCurious and a special welder
21:58 GuShH_ not because of a duty cycle issue, but mostly because of the lack of settings
21:58 ShH_ s
22:00 GuShH_ oh I know, beer and cs:s
22:02 GuShH_ how the hell does anyone frag 2 headshots and end up with 1 life and WIN the match
22:02 GargantuaSauce i'll totally join you in this noble endeavor
22:02 GargantuaSauce whats your steamid
22:03 GuShH_ we can't, due to lag.
22:03 GuShH_ 330ms average between you and me
22:03 GargantuaSauce seriously? :|
22:03 GuShH_ yes... the bottleneck is somewhere after the miami fiber cable
22:03 GuShH_ ie inside my country
22:03 GuShH_ (we come out through miami)
22:04 GuShH_ there's also the added latency from all the surveilance shit they added, which I'm not supposed to know about.
22:04 GuShH_ we are being proxied in fact.
22:04 GargantuaSauce oh boy
22:05 GuShH_ there's no reason why we should have such latency
22:05 Jak_o_Shadows Strictly speaking, does the surveillance work if you put the effort into getting around it?
22:05 Jak_o_Shadows Australia had ideas of an internet filter that wouldn't work and would just make our connections worse
22:05 GuShH_ how would you?
22:05 GuShH_ if all traffic goes through it
22:06 GargantuaSauce wow you don't say. 220 ms to you indeed
22:06 GuShH_ the gov has been investing more in this than on education or safety
22:06 GargantuaSauce that sucks
22:06 Jak_o_Shadows encryption and TOR maybe? Haven't put too much thought in.
22:06 GuShH_ 220! that's a good day, 380 is my average
22:06 GuShH_ yeah let's CS:S through TOR!
22:07 GuShH_ but 220ms still means I'm a 5 year old in terms of FPS gaming.
22:07 Jak_o_Shadows I have played sauerbraten succesfully at 1s lag.
22:08 GargantuaSauce oh take a look at tesseract jak, it's sauer with a new rendering engine that doesn't suck
22:09 GuShH_ at least we have big local servers with up to 64 slots, those are fun
22:21 Jak_o_Shadows The community isn't quite there yet: I liked map editing mostly
22:23 GargantuaSauce yeah me too