#robotics Logs

May 08 2015

06:28 Ubuntivity If you had the chance to have a personal robot, what would you want it to do for you?
06:29 Triffid_Hunter Ubuntivity: cook and clean
06:30 Ubuntivity Constructive answer, Triffid_Hunter. Looking for more :)
06:32 untivity is looking for more awesome answer
06:38 SpeedEvil Cook, clean, mow, hedgetrim, ...
06:38 SpeedEvil weed
06:42 deshipu kill all humans
06:44 deshipu er, meant to say pests
06:44 deshipu kill pests
06:44 deshipu hunt down mice
06:44 deshipu yes, mice
06:44 deshipu and, err, mosquitos
06:44 deshipu cocroaches
06:44 deshipu children
06:47 SpeedEvil conservative politicians.
06:47 deshipu all politicians, really
06:47 deshipu you need to rotate them often
06:47 deshipu or they go bad
06:48 deshipu come to think of it, a swarm of small unobtrusive robots that would constantly explore my apartment and index all my stuff, then let me query for it and lead me to it would be nice
06:49 SpeedEvil If you';re the only one in there, then all you acutally need is a 'where did I put x' thing that remembers where you put it
06:56 deshipu things tend to fall down
06:56 deshipu it would be nice if they could also collect lost nuts and bolts
07:11 veverak deshipu++
07:17 deshipu a cool use case for quadrupeds: https://www.youtube.com/watch?v=5kjeTTLXoP4
07:34 veverak here I ago
07:34 veverak once again thinking about some quadracopter
07:34 veverak :D
07:36 deshipu quadcopters would need to charge too often
07:38 SpeedEvil I was pondering a plug-in quad.
07:38 SpeedEvil Plans stalled when I realised that 80A*240V isn't actually a lot of thrust
07:40 deshipu they could have several slots throughout the garden, and just jump between them, mostly staying in place and shining
07:40 veverak https://www.youtube.com/watch?v=pAvWq0DD8uE&feature=share | this is why I love corexy
07:41 veverak deshipu: I like crazyflie
07:41 veverak 7 minutes of flight, 20 minutes charge
07:41 veverak let's say that with 4 of them, you could have 24/7 company :)
07:41 deshipu you need battery for the lamp too
07:55 deshipu the stuff-indexing robots could look like this: https://www.youtube.com/watch?v=uzfsSA4FqGw
08:15 deshipu so, someone wanted to build himself a robot girlfriend? http://www.dannychoo.com/en/post/27287/Smart+Doll+Plus.html
12:51 deshipu is it just me, or does that lander have *legs*? http://blog.chron.com/sciguy/2015/05/a-europa-lander-is-possible-jpl-scientists-say-and-congress-appears-likely-to-support-it/#21279101=0
13:03 veverak yeah, there are legs
13:05 deshipu I, for one, welcome our new insectoid overlords
13:09 veverak nah
13:09 veverak rebuilded 1/2 of the extruder
13:09 veverak let's how much I broken it up
13:11 deshipu rebuilt
13:12 deshipu and you accidently a verb
13:12 deshipu :)
13:12 veverak O:)
13:17 LiohAu anybody sees a way to make a ball rotate in three axis with only 2 servos?
13:18 LiohAu well my question is not really accurate
13:18 LiohAu let's say I want to articulate an head
13:19 LiohAu (like the human head)
13:19 LiohAu is their a mecanical way to rotate the head in the 3 axis (pan / tilt / roll) using only 2 servos
13:33 deshipu LiohAu: to any position?
13:33 LiohAu no, like the head.
13:33 deshipu which means?
13:34 LiohAu pan : 120°, tilt 120°, roll: 90°
13:34 deshipu you could have two servos like Johnny #5 had
13:34 LiohAu I guess
13:34 deshipu well, but to any position within those ranges?
13:34 LiohAu yes
13:34 deshipu then no
13:34 deshipu mathematically impossible
13:35 deshipu unless you allow only some trajectories
13:35 veverak exactly
13:41 deshipu LiohAu: for instance, you could allow tilting only when looking straight, and otherwise roll
13:42 LiohAu well the system becomes more complicated then, and cost more than just buying a 3rd servo :P
13:44 deshipu certainly
13:44 deshipu you also need an extra pin
13:44 veverak LiohAu: USUALLY
13:45 veverak sorry!
13:45 LiohAu "extra pin"
13:45 veverak LiohAu: usually, you want at leas same number of 'control pins' as degrees of freedom you want
13:45 veverak :)
13:45 veverak and by 'control pins' I mean devices that you can control independently
13:46 LiohAu ok, you're talking about pins like "arduino pins"?
13:46 veverak I am talking about pins more in sense of "control channels
13:46 veverak ;D
13:46 veverak LiohAu: forget it
13:47 veverak LiohAu: "you need at least as many servos as degrees of freedom you want" <- much better :)
13:48 deshipu I meant arduino pins
13:49 deshipu veverak: well, unless you want an uderactuated system
13:49 deshipu which may be workable
13:49 deshipu you may even be able to reach all the points
13:49 deshipu just not through arbitrary trajectory
13:50 deshipu for example, you could make the head hollow, put it on some rolls, and put a small car inside, with one servo for going forward and one for turning
13:50 deshipu as the car goes inside the head, the sphere will rotate
13:50 veverak :D
13:51 deshipu you can rotate it in any axis, just not at once
13:52 deshipu LiohAu: do you really neeed the head tilting sideways? that's rarely useful
13:52 deshipu pan and tilt is usually enough
13:52 LiohAu deshipu: the roll thing?
13:52 deshipu yeah
13:52 LiohAu yes I need it :(
13:53 LiohAu and yes, that's really hard to find a mecanism that handle the 3 dof
13:53 deshipu how about making it roll when you pan to the extreme and try to pan further?
13:53 LiohAu even in my head, it's hard to think at a 3 dof way
13:53 deshipu well, the mechanism is straightforward
13:54 deshipu all the three servos glued to each other at 90°
13:55 LiohAu hm, something with a bracket ?
13:55 LiohAu deshipu: do you talk about something like this : https://www.sparkfun.com/images/tutorials/PanTiltFaceDetection/PanTilt-1L.jpg ?
13:56 deshipu LiohAu: with an extra servo at the top
13:57 LiohAu well, my problem is that the head has an 8" touch screen on it, 2 cameras board, 2 speakers, and 8 electret microphones
13:57 LiohAu I have at least 1kg
13:58 LiohAu as the head is "big" think about a cube having this size : 20*10*10
13:59 LiohAu (which is not a cube since the height is 20.. :D)
13:59 LiohAu So I can easily put the pan servo under that cube.
14:00 LiohAu I guess that I have to add the tilt servo inside the head, or I'll have to use belt/sprocket/chain
14:04 LiohAu I have to go, but i'll be back for questions since it is a topic where i really need help :D
14:05 deshipu LiohAu: how about a Stewart platform then?
14:30 LiohAu deshipu: like that : http://hackedgadgets.com/2009/01/12/lcd-servo-robot-head/ ?
14:41 deshipu you need a third one for pan
14:42 deshipu and a ball bearing
14:42 deshipu like Johnny #5 :P
14:44 veverak stewart platform is neat
14:44 veverak :)
14:46 deshipu https://www.youtube.com/watch?v=WjeptaI2T8E
14:57 veverak printing so far looks awesome
14:57 veverak and I finally found a nice mount point for my webcam
14:57 veverak :)
14:57 deshipu I found a fablab in zurich
14:58 deshipu two laser cutters, cnc router, bandsaw, 4 ultimakers
15:00 veverak (y)
15:44 applepi Hi all. :) I coach FTC robotics for high school students, and originally I was teaching them code and they were learning the mechanics from another guy, but I keep finding myself having to teach solo, so I'm looking for good intermediate level engineering education sources..
15:45 applepi I'm looking for something a little more advanced than "here's a gear, here's a motor, here's a gear ration", but not quite "let's get into dealing with industrial level issues"
15:47 applepi I've previously used the Vex Robotics Curriculum as a good starting point, but I'm not sure where to go from there.. I'm looking for something that gets into next-level topics, like how to drive a gear / shaft with multiple motors and keep them in sync when you need more power, for example.
15:53 deshipu applepi: I have the impression that most people in here are self-taught hobbyists
15:54 applepi deshipu, probably, yeah. Most all of what I know is fairly self taught, but I'd like to be a better teacher, so I'm trying to find a good resource to speed along a bit, if anyone knows of any. :)
15:55 ace4016 hrm, i think you've hit on a weird spot with the topics at hand
15:55 ace4016 there's the hobbyist level stuff, then there's the beginner engineering stuff
15:56 ace4016 there's a nice little gap between the two (not much really, but to a beginner there is a bit)
15:57 f00bar80 anybody knows a freenode # related to Lego mindstorms ?
16:00 applepi yeah.. I need something a bit more than "you can lift things with a chain and increase torque with gear ratios" but not quite industrial-application level stuff... maybe I'll just start looking for an intro mechanical book or something.
16:02 veverak nah
16:02 veverak applepi: best is just to give them project to build
16:02 veverak and teach them how to solve various problems concerning that :)
16:03 deshipu with a big hammer
16:03 veverak of course that project have to hit something more complicated than "use gearbox, motor and ..."
16:03 veverak :)
16:03 veverak applepi: that way they will be able to learn how to solve problems
16:03 veverak not just "pushing static informations into them with hammer"
16:03 veverak and also you will have plenty of thigns to teach them :D
16:03 veverak *things
16:04 veverak deshipu: actually
16:04 applepi veverak, well, they have a year long competition they're a part of, and that's part of my job, teaching along the way, but giving them some building blocks to work with is helpful
16:04 veverak applepi: find something from that competition?
16:04 veverak that would be awesome
16:04 applepi it's not terribly different than code.. start them off with algorithm-ing out what they want it to do, start teaching them how code actually works, etc.
16:04 deshipu a lot of small projects > one big project
16:05 veverak deshipu: true to that!
16:05 veverak anyway
16:05 veverak anybody any tips for "D* algorithm for dummies" ?
16:05 applepi veverak, right, yes, I'm saying *I* am almost equally terrible at mechanics as the kids, and I need to do some learnin'
16:05 veverak or D-lite
16:05 applepi :)
16:05 deshipu veverak: A* you mean?
16:05 veverak no
16:05 veverak D*
16:05 veverak I know A* :D
16:05 deshipu what's D*?
16:05 veverak deshipu: letter with a star after it
16:06 veverak https://en.wikipedia.org/wiki/D*
16:06 deshipu https://en.wikipedia.org/wiki/D-STAR
16:06 veverak upgraded A*
16:06 applepi So when they're like "applepi we want to do ___ but we can't work out how to do it without catching motors on fire" I can respond with better than "lol, me either."
16:06 veverak aaaand I like the basic idea, but want to actually understand it
16:06 veverak applepi: teach them to use IRC
16:06 veverak :) :D
16:08 deshipu interesting
16:08 veverak give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime | < this tells me that people should be teached how to figure things out
16:08 veverak and not just "static information"
16:08 veverak but nah, maybe I was on terrible high school and just hate schools in general than because of ... affection?
16:08 veverak deshipu: D*? definetly is
16:08 deshipu give a man fire, and he will be warm for a day, set him on fire, and he will be warm to the end of his life
16:09 veverak :DDDDDDDDD
16:09 veverak finally perfect spot for webcam for 3d printer!
16:09 veverak http://webcam.veverak.org/stream_simple.html
16:10 deshipu booooring
16:10 veverak it's 3d printing
16:10 veverak it is boring
16:10 veverak and this is base
16:10 veverak deshipu: I will pm you when it hits full speed
16:11 applepi veverak, teaching them to fish is what I'm trying to do, but I need to be able to fish to be able to teach someone else ;)
16:11 veverak yeah, I see
16:11 veverak applepi: for me best is always to solve problems
16:11 veverak I want to build XY so I google how to do it
16:12 veverak and learn stuff that I need to do it
16:12 veverak of course I sometimes doesn't pick what I really needed etc... but that's part of the fun :)
16:12 zaxxon MGS extruder?
16:12 veverak yep
16:12 f00bar80 ppl any comment ?
16:13 veverak zaxxon: you are first one that I know knows it even exist :D
16:13 zaxxon me too, works well, changing filament can be a pain tho
16:13 applepi veverak, I spend a lot of time googling around, yeah, that's where I've found a lot of stuff, I've just been looking for a book I could sit down with and pour through.
16:13 veverak oh, that...
16:13 zaxxon veverak: got it from reprapsource.com as well?
16:13 veverak zaxxon: exactly! :D
16:13 veverak zaxxon: but going to switch to 1.75 soon
16:14 veverak so, I will put him to .... "display case" ?
16:14 veverak you know, my first exruder! :D
16:14 zaxxon hehe :)
16:14 veverak zaxxon: only pain for me "was" flexible material
16:14 veverak but I modified the body :)
16:14 deshipu f00bar80: comment to what?
16:14 zaxxon my first was a wade's on an i2, glad to be rid of it
16:15 veverak also because of fillament cooler I use, I put it little bit down
16:15 zaxxon i see you added a fan, me too, helps a lot
16:15 zaxxon what will you use for 1.75?
16:15 zaxxon extruder
16:15 veverak http://www.thingiverse.com/thing:147705
16:16 veverak or
16:16 veverak http://www.thingiverse.com/thing:673816
16:16 veverak first if single, second if dual
16:17 zaxxon nice! geared stepper on the first?
16:17 veverak I suppose there should be no need to
16:17 zaxxon (i come from a 3mm world)
16:17 f00bar80 deshipu, anybody knows a freenode # related to Lego mindstorms ?
16:17 veverak zaxxon: I too for now :D
16:17 veverak but for 1.75 and good quality hobbed bolt
16:17 veverak you don't need gearbox
16:17 veverak that's one of the motivations to go for it :D
16:19 zaxxon what I wonder about with such designs is hotend stability, had a problem in the mendel with that; there was a tiny bit of room for the hotend to move (not even 1mm at the tip) when filament was forced down, took a long time to figure out :)
16:20 zaxxon but may not be a worry in 1.75 at all
16:20 deshipu f00bar80: if anybody knew, they would answer
16:20 veverak zaxxon: I saw the first one in action
16:20 veverak :D
16:20 veverak it seemed OK
16:20 veverak for the dual ... it's first dual I would consider building
16:20 zaxxon cool!
16:21 veverak anyway, both uses same system to hold the nozzle, which seems OK :)
16:22 zaxxon gotta afk for a while, best of luck with it!
18:00 LiohAu deshipu: stewart platform uses prismatic joint right?