#robotics Logs

Oct 02 2015

00:22 Hyratel suggestion? use something other than 4chan
00:23 Hyratel by "hinge" do you mean coaxial pivot, for support?
00:24 Hyratel a bolt, three nylon washers, and a nylock nut
00:25 Hyratel anonnumberanon, https://www.sparkfun.com/images/tutorials/PanTiltFaceDetection/PanTilt-1L.jpg
00:25 [cube] ever run face detection software on a pi?
00:25 [cube] running a pi webcam
00:26 [cube] something I need to tackle in an upcoming project...
00:27 anonnumberanon Hyratel, this is great, but I want the hinge to mount onto the servo's bottom, like this design which I can't find the parts for, for some reason: http://drewsrobots.blogspot.com/2011/04/adding-second-hinge-point-to-common.html
00:38 anonnumberanon Does anyone know where I can get this female part (plus male would be great) in the first of these pictures? https://2.bp.blogspot.com/-j1N3aKb1ckk/TauPOQFHWEI/AAAAAAAAAUc/Yfb5XWp6pv4/s1600/IMG_0630.JPG
00:40 Hyratel anonnumberanon, you mean a 'weld nut'?
00:40 anonnumberanon Yeah?
00:40 Hyratel https://www.fastenal.com/products/fasteners/nuts/weld-nuts/_/Navigation?r=~|categoryl1:%22600000%20Fasteners%22|~%20~|categoryl2:%22600072%20Nuts%22|~%20~|categoryl3:%22600123%20Weld%20Nuts%22|~
00:40 anonnumberanon Is this the best part to use for this job?
00:41 anonnumberanon The guy glues it, aside from that I'm sure it's a good idea, he didn't seem to complain about it.
00:45 Hyratel dude, it's your build
00:47 anonnumberanon I'm very mechanically shy, I'm an EE not ME !
00:48 [cube] epoxy > glue
00:49 [cube] jbweld is better on metals
00:49 [cube] might want to deep sand/score the metal first before applying it
14:19 deshipu hmm
14:19 deshipu that's a design I have not considered: https://www.youtube.com/watch?v=0Ovp96RAfns
14:24 SpeedEvil Question is how contaminatable
14:29 deshipu higly, from the looks of it
14:29 deshipu but you could include a washing mechanism
17:54 moon_ rue_school are you around homeeee
19:30 veverak nema 11 are sweet
19:45 veverak what would you use
19:45 veverak to drive a stepper motor and have abillity to "lock" the shaft?
19:45 verak wats to lift only nozzle on 3d printer with small (nema 11) ste
19:45 veverak wonder how to setup electronics so stepper holds it in palce
19:45 veverak *place
19:46 veverak but I suppose it should be simple
19:46 Jak_o_Shadows erm. Hmmm.
19:46 Jak_o_Shadows You're not going to have a lot of holding torque are you.
19:46 Jak_o_Shadows Perhaps some sort of locking pin?
19:48 veverak Jak_o_Shadows: I plan to use screws or this
19:48 veverak I mean, axis length should be about 5mm at maximum
19:48 Jak_o_Shadows Nah, like the motor connected to a locking pin
19:48 veverak maybe
19:48 Jak_o_Shadows Or you could use a leadscrew.
19:48 veverak worm gear? :)
19:48 Jak_o_Shadows yeah.
19:49 veverak that would be awesome
19:50 Jak_o_Shadows What about the mechanism from a CD drive?
19:50 veverak I suppose presure that fillament makes whne it's pushed into the nozzle is not strong enough to actually harm the worm gear
19:50 veverak hmm
19:50 veverak on the other hand if I would lift also the extruder it would be much easire
19:50 veverak *easier
19:50 veverak nah
19:50 Jak_o_Shadows I don't actually know how much you're moving
19:51 veverak Jak_o_Shadows: it's for dual extruder
19:52 veverak I want dual extrusion version where I can lift nozzle that is not printing
19:52 veverak given that I still prefer direct extruders
19:53 veverak lifthing nozzle and extruder as one body would get mi rid of the problem, that fillament pushes the nozzle down
19:53 veverak on the other hand it's much bigger weight
19:53 Jak_o_Shadows Indeed.
20:03 Hyratel I think I can see a way that'd work
20:03 Hyratel a rocker arm that lowers one and lifts the other jsut a fraction
20:05 veverak actually
20:05 veverak http://i.idnes.cz/12/042/cl6/FDV429e93_vacka.jpg
20:05 veverak this is basic principle that would make perfect lifting
20:05 veverak :)
20:05 veverak I need to lift it only by around 5mm
20:06 Jak_o_Shadows Well, i'm pretty sure the calculations for force and torque wouldn't be too difficult
20:06 veverak yeah
20:06 veverak that seems
20:06 Jak_o_Shadows It'd be a reasonably well known thing.
20:06 veverak like it could work!
20:06 veverak nah
20:06 veverak gn
20:06 veverak it's 3am for me
21:36 copycat how do people typically do motion control for robotic arms/hands?
21:36 copycat is it overkill to get a motion controller from delta tau/trio/galil etc..
21:41 Tom_itx you could use linuxcnc
21:43 ace4016 for arms/hands, most of that is kinematics; if you don't care to implement the kinematics, get a controller, otherwise make your own?
21:43 Tom_itx linuxcnc has kins but i've not used it
21:47 copycat ah, i just wanted to know options to a commercial motion controller since thats all i've known
21:49 Tom_itx linuxcnc is used on commercial cnc
21:50 Tom_itx https://www.youtube.com/watch?v=iy1Mb6G_VJ0
21:50 Tom_itx https://www.youtube.com/watch?v=Nn1bJ3YAQdI
21:51 Tom_itx for a couple examples
21:52 Tom_itx best of 2nd one starts at 3:46
21:56 Tom_itx https://www.youtube.com/watch?v=6_3kg_m0cfc
21:56 Tom_itx fanuc robot with linuxcnc
21:56 Jak_o_Shadows A lot of the time the kinematics is the fun part fort peple
21:57 ace4016 indeed
21:57 copycat sorry if i sound ignorant, but isn't it a solved problem?
21:58 ace4016 kind of
21:58 ace4016 for a set geometry
21:58 ace4016 there are still some issues though
21:58 Jak_o_Shadows Yeah, it's a solved problem, but in most cases it doesn't have a closed form solution
21:58 ace4016 ^
21:59 ace4016 various works to do funky things and run it in certain environments
21:59 copycat closed form solution?
22:00 Jak_o_Shadows straightforward formula, as opposed to an iterative proccess.
22:00 Jak_o_Shadows : straightforward formula, as opposed to an iterative proccess.
22:01 copycat i'm not sure i follow..
22:01 copycat could you elaborate/
22:01 Jak_o_Shadows For some systems, you can do some trig and get a formula that will give you the numbers you need.
22:02 Jak_o_Shadows For others (such as most robot arms), there isn't a closed form solution, so you ave to use more complicated iterative techniques
22:02 Jak_o_Shadows These techniques generally work by moving it a bit, seeing what happens, move it again
22:02 Jak_o_Shadows (more or ess)
22:04 copycat do you mean tuning?
22:05 copycat i'm also curious how they manage to offer robot arms with servomotors so cheaply at 350
22:05 copycat https://www.kickstarter.com/projects/1128055363/7bot-a-powerful-desktop-robot-arm-for-future-inven
22:08 ace4016 the servo motors aren't that pricey is why
22:08 Jak_o_Shadows I wanna know how they make the work space diagrams nicely
22:09 Jak_o_Shadows Like, I could probably do it by hand, but ew, no.
22:13 ace4016 i probably shouldn't, but i think i'll make a CNC next after the kiln is done
22:14 Jak_o_Shadows I'll get back to working on the 3d printer within 2 months
22:15 ace4016 Tom_itx, funny that the first video you link is the reason i want/need a CNC :P
22:20 ace4016 CNCs making humanoid models just look like they're groping the people
22:41 ace4016 hrm...