#robotics Logs

May 28 2015

02:20 Anniepoo howdy
02:39 rue_bed so, I got my trainer working with a playback file
02:39 rue_bed of sorts, its waypoint, not realtime
02:45 deshipu do you have encoders?
07:21 veverak important question
07:21 veverak which name I should give m robot?
07:23 Tom_itx hey you
07:23 SpeedEvil botfly
07:24 deshipu cringy
10:56 LiohAu rue_house: here?
10:58 LiohAu well ping me when you have a little bit of time (today or another day) so we can discuss the servo direct drive topic :)
12:28 sherrardtr4129 hello
15:28 LiohAu deshipu: here?
15:28 deshipu LiohAu: where?
15:28 LiohAu on this channel :d
15:28 LiohAu and on your IRC client ^^
15:28 LiohAu I have a question, maybe you'll have the answer
15:29 deshipu who knows
15:29 deshipu we will never know, unless you ask the question
15:29 LiohAu I'm looking for a way to wire a cable from the servo horn to the mecanical parts of the hand which i'm building
15:30 LiohAu I was thinking to use staples
15:30 LiohAu any better idea?
15:30 deshipu zip ties?
15:31 LiohAu which one?
15:31 LiohAu deshipu: you mean this : http://www.plumeria.care/wp-content/uploads/2014/10/21.6517.jpg ?
15:31 deshipu http://flaglerlive.com/wp-content/uploads/zip-ties.jpg
15:32 deshipu yeah, there are small ones
15:32 LiohAu ok, but now that won't be food
15:32 LiohAu good*
15:32 LiohAu -now+no*
15:32 LiohAu If I use zip ties, the wire can move around it
15:32 deshipu I also used cable sleeves
15:33 LiohAu it's not accurate enough. The wire will be used as tendon, so if we look at an human hand, it is accurately fixed to a place on your bones
15:33 deshipu http://www.cabletiesandmore.com/images/braidedsleeving/PTNtopimage2.jpg
15:33 deshipu aah
15:33 deshipu that kind of wire
15:33 deshipu not a cable
15:33 LiohAu talking about wire like dyneema
15:34 LiohAu sorry, you though I was talking about electronic wire ?
15:35 LiohAu I really don't know which word is the good one, wire/cable.
15:36 deshipu wire is correct
15:36 deshipu I just didn't have context
15:37 deshipu so, there are also sleeves for servo wire
15:37 deshipu http://www.hobbyking.com/hobbyking/store/__13036__Control_Rod_ABS_Sleeve_1pc_bag_.html
15:37 deshipu I just discovered that
15:37 deshipu it's like the brake wire in a bicycle
15:38 LiohAu I think I did not explain correctly what i'm looking for
15:39 LiohAu but your link will be usefull for another part :P
15:41 LiohAu deshipu: What I'm looking for, it is a way to stick/tie the end of the wire to the mecanical part that will be moved when that wire is towed on the other end by the servo.
15:41 LiohAu stick/tie/bind whatever is the word ^^
15:44 LiohAu for example, a linear actuator is bound to a part like this one : https://www.servocity.com/assets/images/Mounting_bracket_with_bushing.jpg
15:44 LiohAu but this is way to big to big integrated in a robotic hand
15:47 SpeedEvil LiohAu: go and look at a human skeleton and ligament structure
15:47 LiohAu Since i'm building the fingers with 3d printed plastic, I don't think that I can design a finger that contains the support for the wire, since it will be too small and so weak.
15:47 LiohAu SpeedEvil: I did
15:47 LiohAu SpeedEvil: the tendon seems to be "sticked"
15:47 LiohAu (at least in the diagram I looked at)
15:49 liohau_ SpeedEvil: http://imgur.com/TJO0z4Q
15:49 LiohAu as you can see, it looks like if the tendon was just glued to the bone
15:51 SpeedEvil That's because it basically is
15:51 LiohAu yes :) but how to reproduce that if homemade stuff? :d
15:52 LiohAu I was thinking to stapples, but they won't resist to the tractions, right?
15:54 LiohAu SpeedEvil, deshipu: what do you think, if I tie a knot on this : http://www.rona.ca/images/3505637_L.jpg ?
15:54 LiohAu and screw this in my plastic phalax
15:55 LiohAu phalanx*
15:58 SpeedEvil Sorry, I'm not up to basic mechanical questions at the moment, it's practically impossible without knowing what tooling and clue you have
15:59 SpeedEvil And what forces you hope for
16:00 LiohAu I have a screwdriver :P and for the hand I'm building I hope to be able to lift 2kg.
16:00 LiohAu the servos i'll use have a torque around 20kg.cm
16:02 deshipu LiohAu: well, usually you just have a piece of wire bent in an L
16:03 LiohAu deshipu: wire like dyneema?
16:03 deshipu LiohAu: or, if you only pull, just make a loop at the end of the wire?
16:03 deshipu LiohAu: wire like steel wire
16:03 LiohAu no no, i'm using dyneema
16:03 deshipu http://www.hobbyking.com/hobbyking/store/__18758__HK190_Servo_Pushrod_.html
16:04 deshipu then you attach your wire to this
16:04 deshipu with string and glue
16:05 LiohAu that's what is called a clevis?
16:06 deshipu take a piece of steel wire shaped like U, put it through the servo horn, then insert your duneema wire inside the U, wrap with a string, put a drop of glue on top so that it sinks into the string
16:06 deshipu I have no idea how it is called in English
16:07 deshipu I guess so
16:07 LiohAu well this is for the servo side, this part is already clear :P
16:07 LiohAu I was more looking for a way to bind the other part of the string
16:08 LiohAu I said wire since the begining, but I think that's what you call string.
16:08 deshipu any kind of hook or clevis should work
16:09 deshipu two loops with a bolt inside
16:09 deshipu so that you can remove it
16:09 deshipu you will also probably want some way of adjusting tension
16:11 LiohAu deshipu: good idea
16:11 LiohAu because I was thinking to cut the string.. but this is not really easy to make tests in this case..
22:14 sherrardtr4129 hello
22:14 rue_house hey!
22:14 rue_house whats ornage with black stripes
22:15 sherrardtr4129 I don't know :0
22:17 sherrardtr4129 tiger robots?
22:39 sherrardtr4129 anyone working on any neat projects?
22:47 zhanx Evening
22:52 sherrardtr4129 hello