#robotics Logs
Aug 08 2012
#robotics Calendar
00:23 rue_house its not a mig tip for a 3d printer, it would be a oxy/acetylene tip
00:36 rrywolf curls up on spacekitteh for bed
00:37 acekitteh cuddlepet
00:56 ShH hands rue_house an angle gri
00:59 rue_house http://eds.dyndns.org/~ircjunk/projects/reprap/p1040478.jpg
00:59 rue_house ok see what I made with it?
00:59 rue_house http://eds.dyndns.org/~ircjunk/projects/reprap/p1040477.jpg
00:59 rue_house http://eds.dyndns.org/~ircjunk/projects/reprap/p1040476.jpg
00:59 rue_house http://eds.dyndns.org/~ircjunk/projects/reprap/p1040475.jpg
01:18 GuShH rue_house: how much power are you dissipating on that resistor?
01:19 ShH slaps rue
01:19 rue_bed >8-/
01:20 GuShH how much power are you dissipating on that resistor?
01:20 rue_bed heh, "10 to 20W"
01:20 GuShH is that enough?
01:20 rue_bed thats what they said
01:20 rue_bed hits over 100c in less than 2 mins
01:20 GuShH but what about when you place a "load"
01:20 rue_bed havn't tried it with the quartz, but should be better
01:21 rue_bed dunno
01:21 GuShH it should have a bigger thermal mass
01:21 rue_bed I'v done this exactly never times before
01:21 GuShH as to keep the temperature stable as you feed through material
01:21 GuShH because it may not be able to keep up
01:21 GuShH ehh me neither, but these are all assumptions :p
01:21 rue_bed its 5.1 ohms
01:21 rue_bed against 12V
01:21 GuShH it actually isn't, when it's hot :p
01:21 rue_bed yea
01:22 rue_bed not when its cold either
01:22 rue_bed the lowest reported resistor used is 4.7
01:22 rue_bed the 5.1 was all I had with long leads
01:22 GuShH resistor value shouldn't matter, you could use a coil of wire... just feed it with constant current
01:22 rue_bed in "5w"
01:23 rue_bed meh, I may use a 24V supply anyhow
01:23 GuShH that's the problem with big values
01:23 rue_bed technically, my good iron is 15W
01:23 rue_bed I think it'll be ok
01:24 rue_bed maybe I'll watch the duty
01:24 GuShH but I bet theres a bigger thermal mass in that iron's tip
01:24 rue_bed no
01:24 rue_bed its a light iron
01:24 rue_bed melts solder great, dosn't cook your hand
01:24 rue_bed I think less mass is better
01:24 GuShH only if you can pump more energy
01:25 rue_bed let the pid loop work it out
01:25 GuShH less means faster response
01:25 rue_bed yes
01:25 GuShH but also prone to problems
01:25 ShH sh
01:25 rue_bed think of it like a motor/mass
01:25 rue_bed faster control when there is less mass
01:25 GuShH no, no motors! I haven't got that turbine off the shaft yet.
01:25 GuShH stupid rust.
01:26 rue_bed cut/drill?
01:26 rue_bed you trying to save the turbine or the shaft?
01:26 GuShH both
01:26 rue_bed heh
01:26 rue_bed trying to replace the bearing then?
01:26 GuShH so I've been heating it and trying to push the shaft out
01:26 rue_bed did you file the rust away?
01:27 rue_bed /sand
01:27 GuShH there doesn't seem to be any on the top portion, just inside
01:27 rue_bed so you cant get to it?
01:27 GuShH I got it most of the way in, almost flush
01:27 rue_bed impact driver to work the shaft out
01:28 rue_bed heavy turbine right?
01:28 GuShH this is what happens when you neglect things (well, it's only been mine for 6 months, they neglected it for over a decade)
01:28 GuShH it's pretty small stuff.
01:29 GuShH I got some awesome and cheap rust converter with aluminum powder + enamel, it's got a really nice finish.
01:30 GuShH costs just as much as the regular stuff in other places, for no good reason.
01:30 GuShH it is a bit thinner, but that's OK since I spray paint it and I thin it anyway, of course I may be getting less actual paint but who cares.
01:31 GuShH the idea is to get rid of the poop build-up and then to refinish it all
01:52 theos GuShH you stopped joining ##electronics ?
01:53 GuShH yes
01:53 theos why?
01:53 GuShH tired of some idiot/s
01:53 theos i thought you quit irc :/
01:53 theos ok
01:53 ShH hands theos some c
01:53 theos :D
02:46 ShH stares at the dust
02:48 GuShH I'm starting to think this burner needs an air filter.
03:04 Sefid_Par From where should I start learn to make a robot?
03:12 theos heh you again :)
03:13 theos try this http://www.electronicsteacher.com/robotics/robotics-tutorial/beginners-robotics/
03:14 Sefid_Par theos: I love you :)
03:14 theos >.>
03:15 ShH puts Sefid_Par and theos in a
03:15 theos noo noo!
03:15 Sefid_Par :)))
03:16 GuShH yes! yes!
08:16 zhulikas hey guys
08:16 zhulikas I was wondering about a building material I could use in the beginning
08:16 zhulikas I don't want to buy fancy expensive stuff yet
08:16 zhulikas like VEX construction kit
08:17 zhulikas although I'd love to have one
08:17 zhulikas but for now, any ideas what could I use to make a sturdy-enough robot?
08:17 zhulikas like - something what I could find at home
08:25 zhulikas threads and toothpicks might be a way to go
08:36 rue_bed I suggest avoiding wood and cardboard
08:37 rue_bed zhulikas, motorization is the hardest part, you really want to find things to strip down for parts, like old computer printers
08:40 zhulikas I am building a "robot hand"
08:40 zhulikas it's stationary
08:40 zhulikas I just need some material to connect the whole thing and it should hold at least it's on weight during the motion
08:41 zhulikas but old printers is a good idea
08:41 zhulikas there is an electronics scrapyard not far from where I live
08:41 zhulikas I might find some useful parts
08:49 Squint toys with moving parts
08:54 delinquentme I'm looking to seal concrete with some kind of non-reactive seal that I can preferably brush / spray on .. thoughts?
08:55 GuShH furrywolf: might end up using the lp-10 grease in the grooves after all...
08:59 rue_house zhulikas, tell me about he hand you want to make
09:00 zhulikas I attach one end of it to the table, have multiple servos (maybe steppers later) and control it's movement so I can point the tip of this 'hand' to any point in 3D space around the base of it
09:01 rue_house ok
09:01 zhulikas I make it configurable enough so I can replace parts
09:01 zhulikas get better parts later for more precision
09:01 zhulikas that's it for now :)
09:09 rue_house have you built much before?
09:10 zhulikas uhm
09:10 zhulikas actually I've already built it with two servos
09:10 zhulikas so it works in 2D
09:11 zhulikas now I need more servos to make it work in 3D
09:11 zhulikas and improve equations
09:11 rue_house cool
09:11 rue_house can I see it?
09:11 zhulikas https://dl.dropbox.com/u/6054484/IMG_20120715_174842.jpg
09:11 rue_house so does it go around and up and down?
09:11 zhulikas just don't laugh :D
09:12 zhulikas I can feed it coordinates
09:12 zhulikas (x, y)
09:12 zhulikas and it will move the tip to it
09:12 rue_house :) pencils, cool
09:12 zhulikas or I can draw a bezier curve and specify a delay between every coordinate to make a motion
09:12 rue_house you should make it counterbalanced!
09:12 rue_house good work
09:12 zhulikas thanks
09:12 zhulikas :)
09:13 rue_house so where do you want to add to it?
09:13 rue_house or do you want to change it all up
09:13 zhulikas it actually is counterbalanced. Vertical stance is 90degrees (in 0 - 170) angle for base servo
09:14 rue_house you can put a counterweight on the top arm
09:14 rue_house its good practise for large robots
09:14 zhulikas hmm
09:15 rue_house your bottom one too
09:15 rue_house O---o----------
09:15 zhulikas I am not entirely sure why would I want to do that
09:15 zhulikas and right now it is deconstructed
09:16 zhulikas and instead of pencils I plan to use toothpicks with threads
09:16 rue_house then the motor dosn't have to extert any force to keep the arm segment in position
09:16 rue_house just to move it
09:16 rue_house zhulikas, like bicycle brake cables to control it but smaller yes?
09:17 zhulikas http://cdn.styleforum.net/0/08/089ed458_thread.jpeg
09:18 rue_house http://www.idasa.com/newportal/assets/images/productos/img_ofertas_00.jpg
09:19 rue_house the big wedge on the back is a counterweight for the top arm segment
09:19 zhulikas aaa
09:19 zhulikas like this
09:19 rue_house the two big cylinders you see there are actually springs that effectivly counterweight the lower arm segemnt
09:19 rue_house http://www.globalrobotsusa.com/images/ABB-irb-6000-with-S3-M93-cabinet.jpg
09:20 rue_house those cylinders are not hydraulics
09:20 zhulikas actually I noticed that it's making a sound when in certain positions (indicating it requires force to keep in position)
09:20 zhulikas so that might be a good idea
09:21 rue_house http://eds.dyndns.org/~ircjunk/robots/arm4/p1010990.jpg
09:21 rue_house that one is designed after those ABB robots
09:22 rue_house http://eds.dyndns.org/~ircjunk/robots/arm4/p1010986.jpg
09:23 zhulikas hmm springs
09:23 rue_house see how the lower the lower arm segments go, the more is stretches the springs
09:23 rue_house in the big ABB robots, instead of springs they use big pneumatic cylinders
09:23 rue_house easier to adjust
09:24 zhulikas I'll be fine with springs
09:24 zhulikas actually now I think it might be really fun
09:24 rue_house :)
09:24 zhulikas to get like a thousand toothpicks
09:24 zhulikas good thread
09:24 zhulikas some glue
09:25 rue_house have you ever made a balaanced mobile?
09:25 zhulikas and make a construction!
09:25 rue_house I want to show you this too...
09:25 rue_house where is it
09:25 rue_house http://3.bp.blogspot.com/_BijOZUNFzJM/Swp0UNpabqI/AAAAAAAAAHc/ywiq9mLbNTM/s1600/M98-abb-irb1400-s4c-from-germany-arm.jpg
09:25 rue_house meant to post that tooo
09:26 rue_house http://i.ytimg.com/vi/omvilpsd3sc/0.jpg
09:26 rue_house see that?
09:26 rue_house the control cords are just (basically) fishing line inside a 'tube' made out of alternated tube and sphere beads
09:27 rue_house http://farm3.static.flickr.com/2066/2568800635_28d56591e4.jpg
09:27 rue_house hehe, I think it was made with a 3d printer too
09:28 zhulikas mmm I want a 3d printer :|
09:28 zhulikas again, it's still too expensive
09:28 rue_house yea, I'm building one
09:28 zhulikas maybe I could find a place where they print the parts cheaply
09:28 rue_house I'm at $300 so far, looks like sooner or later it'll need another $100
09:28 zhulikas hmm
09:28 zhulikas not that much thoug
09:29 rue_house I'm learning tho, I think I can work out a way to make them cheap ($20)
09:29 zhulikas uhm
09:29 zhulikas really?
09:29 zhulikas that doesn't sound right
09:29 rue_house I'll work on it
09:30 zhulikas but I'd love to spend only 20$ on such device :D
09:30 rue_house http://www.youtube.com/watch?v=omvilpsd3sc
09:30 zhulikas also I wonder where can I get compact servos/steppers
09:30 zhulikas like really compact
09:30 zhulikas yet quite powerful
09:31 zhulikas I think my current servos' torque is around 4kg
09:31 zhulikas hah, intel
09:31 zhulikas if I were at intel and had financing for such things
09:31 zhulikas my hand would have more than three fingers
09:32 zhulikas I've seen a design with such lines
09:32 zhulikas but it's elastic line
09:32 Triffid_Hunter zhulikas: http://www.thingiverse.com/search?q=hand
09:33 zhulikas so it's not precise when you actually put some weight on it
09:33 Triffid_Hunter now all you need is a 3d printer :)
09:33 Triffid_Hunter or at least access to one, got a local hackerspace?
09:33 zhulikas yea
09:33 zhulikas but I've been there a year ago
09:33 zhulikas and didn't see a printer anywhere around
09:34 zhulikas although I know there is a company somewhere in the city
09:34 zhulikas my friend is intern there
09:34 zhulikas and they are making software for industrial 3D printers
09:34 Triffid_Hunter reprap was very different a year ago, I'm sure there's at least one in your are
09:34 zhulikas so I guess they might have a couple of printers lying around
09:34 Triffid_Hunter area*
09:40 zhulikas haha, awesome
09:40 zhulikas I just googled for reprap in my town
09:40 zhulikas and accidently got into a blog of one dude who studies electronics in the same college
09:40 zhulikas and he owns a reprap
09:41 zhulikas although I met and spoke to him only once :D
09:46 Triffid_Hunter zhulikas: tada :)
09:55 zhulikas I also wonder about this: http://www.robotshop.com/vex-tripack-bundle-hardware-motion-metal.html
09:57 zhulikas might be the way to go
10:11 Triffid_Hunter zhulikas: heh that price is halfway to a 3d printer if you're good at scavenging
10:11 zhulikas :DD
11:24 furrywolf GuShH: bushings generally like something that's closer to oil than grease. plain motor oil is common for a lot of bushings.
17:17 teh_pwnerer hey everyone i am a total noob to robotics... how do i get started making programmable bots?
17:33 moriarty teh_pwnerer, you pwn one until they become brain-wash.. i mean programmable
18:08 Skwint teh_pwnerer, google "$50 robot"
18:12 teh_pwnerer skwint; that sounds really promising thank you for the link
19:08 Skwint the rest of society of robots has some useful stuff too
20:33 home hey guys
20:33 home I think its been like forever since I have been on here..]
20:33 home been busy.....
21:05 furrywolf http://motherboard.vice.com/2012/8/6/nasa-s-mars-rover-crashed-into-a-dmca-takedown
21:05 home lol
21:11 furrywolf thank our wonderful government for passing laws that encourage this, care of corrupt politicians.
21:58 furrywolf welder no worky. :(
21:58 furrywolf very loud buzz followed by profuse magic smoke release followed by inverter tripping on overload.
21:59 furrywolf I can't spot the source of the magic smoke release, though. no signs of residue on parts.
22:00 furrywolf probably check the diodes first, just because it's usually the diodes...
22:04 furrywolf it uses those stupid little pellet diodes that always fry
22:04 Tom_itx check shorts in odd places since it set out and likely got wet
22:04 furrywolf first I'm checking "odd" places like the diodes. brb. :)
22:10 furrywolf one half of the diodes measured dead short, spotted the magic smoke as having come from the wire to one of the diodes on that side, pulled the wire, unit now makes happy buzzing, feeds wire, etc.
22:11 furrywolf it has four diodes in parallel on each half of the rectifier, the one I pulled the wire to measures dead short.
22:12 furrywolf brb, going to do a test weld... I figure if I stick to less than 3/4 power, it should be fine with 3/4 the diodes connected.
22:25 furrywolf liner is shot, but welder otherwise seems to wok.
22:25 furrywolf work
22:25 furrywolf so just need to get one replacement diode
22:26 furrywolf it's a stupid kluge using four of those little pellet diodes in parallel... one of those designs where you wonder how it ever worked...
22:26 furrywolf what's the proper name for those little pellet diodes, anyway?
22:27 Tom_itx i'm not sure
22:27 furrywolf of course, I probably should replace all four on that half of the rectifier, because otherwise either the old three or the new one will take all the current...
22:28 furrywolf no obvious markings on them
22:30 furrywolf more proof this welder is garbage... nothing but garbage uses these diodes. heh.
22:31 furrywolf they didn't even use a proper clamp... they're sandwiched between two layers of fiberglass with a bolt in the middle, bending them.
22:32 furrywolf well, fiberglass on one side, aluminum on the other.
22:32 furrywolf nothing resembling proper heatsinking
22:33 rue_shop3 furrywolf, aluminum windings or copper?
22:39 furrywolf aluminum
22:39 furrywolf I thought they were copper when I glanced at it yesterday, but looking at the wiring, it's just old aluminum.
22:42 rue_shop3 not good
22:42 rue_shop3 :) I think you have a paperweight, you can prolly get it going anyhow
22:43 rue_shop3 you gonna redo the diodes?
22:43 rue_shop3 defiitly clean and reconnect the transformer leads, prolly none of the m conduct right now
22:43 furrywolf transformer leads seem fine
22:44 furrywolf and it's currently welding, just I haven't tried turning it over half power to avoid frying the remaining diodes.
22:45 furrywolf everything I've ever had with these stupid pellet diodes has fried. I think they have no way to dissipate heat, and the results are just what you'd expect...
22:45 rue_shop3 get some alternator diodes
22:46 furrywolf hrmm, one of my li-ion cells for my flashlight seems to have died.
22:47 furrywolf it was working, I charged it, and now it doesn't.
22:48 furrywolf I didn't run it completely dead... I only used the light for a few minutes, then recharged it just to make sure it was fully charged for the next use.
22:56 furrywolf http://weldingweb.com/attachment.php?attachmentid=55279&d=1283706697 finally found a picture of them!
22:57 furrywolf those evil fuckers. ALWAYS the problem. when you see them in something, figure they're the problem.
22:58 furrywolf they run >20A through them, with no heatsinking other than the bit that escapes through the (non-greased) contact pads.
22:58 furrywolf just the contact resistance alone (they're clamped, not soldered) is probably enough to get them pretty hot
23:02 rue_house I think my ups is in trouble
23:02 rue_house oh, no I hadn't booted back up
23:02 rue_house these power outages are getting annoying
23:03 rue_house I can get a 8kw wholesale for like $1400, its making me think
23:03 furrywolf 8kw of what?
23:03 rue_house genorator
23:04 furrywolf ah
23:04 furrywolf it helps if you don't leave words out. you were talking about upses last. :P
23:04 rue_house I have to rebuild the carb weekly on the one i have
23:04 rue_house from thepower outage context you were supposed to infer :)
23:04 rue_house that or a ups
23:05 furrywolf sounds like you're not doing a very good job, then. lol
23:06 furrywolf yes.
23:06 furrywolf and you were talking about your ups being in trouble.
23:06 furrywolf so the logical conclusion would be you were looking at a 8kw ups to replace your troubled one.
23:06 rue_house yea, my UPS is only 5kw
23:07 rue_house the one on this computer is a 36V 1100W 8Ah online truesine ups
23:08 furrywolf my house is on an apc smart-ups 1000, with the exception of the microwave, toaster, chop saw, and welder, which are on a dimensions 2600W inverter
23:12 e_shop3
23:12 theos ^
23:16 furrywolf ?
23:21 furrywolf the dimensions inverter is old, and modified sine, but I've yet to find something it can't power.
23:21 furrywolf 1.5hp compressor? no problem. MIG welder? no problem.
23:24 furrywolf hrmm... silicon diodes are all pretty standard in terms of forward voltage, no? should I replace just the bad diode?