#robotics Logs

Jan 17 2014

01:15 totic English is my third language and sadly my vocabulary is a bit limited in the mech-e area
01:16 totic I am trying to extend the little stick that comes out of a motor to be longer
01:16 Jak_o_Shadows shaft?
01:16 totic yeah I am trying to extend the shaft of a motor
01:16 totic what do you call the thing I can use to do that?
01:16 GargantuaSauce coupler
01:17 totic awesome
01:17 totic thanks
01:17 GargantuaSauce no problem
01:17 GargantuaSauce what are you building stark
01:18 totic I am making my blinds go up and down automatic
01:18 totic so just a motor, a relay and an arduino
01:18 totic nothing to fancy
01:18 GargantuaSauce a limit switch or two may also be advisable
01:19 totic I was going to use a sonar to measure were the blinds are to stop them
01:19 totic when the are too far and too close
01:20 GargantuaSauce cool, hope that works for you
01:20 GargantuaSauce my experience is that those are...very imprecise but it'll probably do the trick
01:20 totic it works but the motor pulls the rope and then becomes too messy
01:20 totic so I want to make the "shaft" longer
01:21 totic is there a nice place were you guys order parts from like gears and stuff?
01:21 GargantuaSauce oh so you really want a winch
01:21 totic I am looking at http://www.servocity.com/html/shafting___tubing.html
01:21 GargantuaSauce are you in the US?
01:21 totic yes
01:21 totic NY
01:21 totic NYC
01:21 GargantuaSauce mcmaster-carr will have pretty much anything you can think of
01:21 totic the winches that I have been seeing are too powerful for what I have seen
01:22 totic a 24 DC motor is already doing the job
01:22 totic but I have to expand the shaft a bit
01:22 GargantuaSauce i just mean stick a spool on there instead of using the shaft as one
01:23 totic yup
01:23 totic I tried using a wheel "base", by removing the rubber part of it
01:23 totic but it I don't get why it stopped being able to pull the blind down
01:23 totic I thought the extra torque would help
01:24 totic but maybe its adding more friction
01:24 GargantuaSauce oh it's the opposite of extra torque
01:24 totic so wait, more length removes torque?
01:24 totic isn't it distance X force?
01:24 GargantuaSauce it requires more torque
01:25 totic oh, you are right, I was thinking of it the other way
01:25 GargantuaSauce yeah
01:25 totic yeah so without the wheel it works fine
01:25 totic it can pull the blind up and down
01:26 totic I just have to measure the DC motor shaft when my caliper arrives (just ordered one)
01:29 GargantuaSauce a ruler will do in a pinch, it's usually a multiple of .25mm which can be eyeballed
01:29 totic it should be arriving tomorrow
01:29 GargantuaSauce ah ok
01:29 GargantuaSauce i am used to ordering things from china and waiting a month :)
01:30 totic jesus
01:30 totic Amazon does free delivery if you have prime
01:30 totic mcmaster seems crazy expensive
01:30 GargantuaSauce yeah it is mostly industrial market stuff
01:31 GargantuaSauce excellent if you need something very specific and high quality
01:31 totic yeah it seems like it
01:31 totic perfect if someone else was bankrolling my little projects
01:32 totic a shaft coupler is $7.34 minimum
01:32 totic Any other recommendations of websites for hobbiests, something that won't cost me an eye and a leg
01:33 GargantuaSauce well there's all those "maker-market" sites which are generally very overpriced also
01:34 totic I just find it crazy that for such a small piece of metal with two screws the charge so much
01:34 GargantuaSauce for stuff like this ebay generally gets you the lowest price
01:34 GargantuaSauce you just might end up waiting a bit
01:36 GargantuaSauce the thing about something like a shaft coupler is it has to be machined to a pretty tight tolerance or it's useless
01:36 GargantuaSauce and precision and cheapness have an inverse relationship
01:37 GargantuaSauce i cant find shaft couplers for less than like $4.5
01:37 totic what I am doing is just removing the plasting from the wheel
01:37 totic it has a shaft inside of it
01:38 GargantuaSauce what i would suggest doing is obtain a length of dowel, 1/4" or 3/8" or whatever the smallest your local hardware store has
01:39 GargantuaSauce drill a 3mm hole or whatever it is in one end
01:39 GargantuaSauce stick some glue in there, jam it on
01:40 GargantuaSauce or find a relatively thin spool, i think they might be used for thread or textiles a lot, ribbon or something
01:40 totic yeah, I don't have that many tools, I used to work in a university and they had an amazing machine room, so my tool set is limited. I am starting to build up
01:40 GargantuaSauce the walls/edges of a spool will certainly be beneficial in making the thing not turn into a terrible pile of tangle
01:41 totic I also built this week a little sprinkling system for the plants in my apartment
01:41 totic don't know what else to automate after this
01:42 GargantuaSauce sounds like it'll be time to build something mobile!
01:43 totic I once worked in the darpa grand challenge car robot
01:43 totic but was more doing the CS stuff
01:43 GargantuaSauce where are you at on the electronics side of things?
01:43 GargantuaSauce would probably be worth learning to move away from the arduino
01:44 totic I have a degree in EE and CS from MIT :)
01:44 totic I am just lazy
01:44 GargantuaSauce lol
01:44 totic don't really feel like having to program a micro controller
01:45 totic my ee is pretty rusty now days
01:45 totic its been years since I have really used it
01:45 totic college burned me up and I hadn't built anything non software in ages
01:45 totic also I hate having to wait for parts
01:46 GargantuaSauce well my suggestion is certainly to start messing with a bare microcontroller
01:47 totic what for?
01:47 totic besides it being much cheaper ofcourse
01:47 GargantuaSauce for preparing to move past single-function devices running software written in that dismal ide
01:48 totic you can always write it in emacs like I do
01:48 GargantuaSauce okay moving past that hideous api then
01:48 totic anyways lets say I bite
01:49 totic what micro controller do you recommend now days?
01:49 GargantuaSauce i use ST's arm micros
01:50 GargantuaSauce the stm32f4discovery has run most of my stuff, i am preparing to start making my own boards with the lower-power f0 and f1 soon though
01:50 GargantuaSauce the f4 has a floating point unit and is more powerful than my first two desktop computers
01:50 totic This thing: http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF252419
01:51 GargantuaSauce that's the one
01:51 totic nice, they are cheap
01:51 totic $15
01:52 totic the price of 3 shaft couplers!
01:52 GargantuaSauce yeah. i think they're sold at or below cost
01:52 GargantuaSauce there are some fancy peripherals on there that i don't even bother to use
01:52 totic what do you write the code in ? C
01:52 GargantuaSauce yes
01:53 GargantuaSauce some people use c++ but i am not super keen on c++ in an embedded context
01:53 totic haven't done C in 7 years, might be nice to pick it up again
01:55 totic you do robotics mainly as a hobby or for work?
01:56 GargantuaSauce it's a hobby now but am kind of thinking of making it an entrepreneurial pursuit
01:57 totic built anything cool?
01:57 GargantuaSauce sort of
01:58 GargantuaSauce http://www.youtube.com/watch?v=2vBi6LNklRg
01:58 totic wow nice!! very impressive
01:58 totic how many servos?
01:58 GargantuaSauce 24
01:58 totic nice!!
01:58 totic the rest 3d printed?
01:59 GargantuaSauce aluminium
01:59 totic you milled them yourself?
01:59 GargantuaSauce mostly prefab brackets made by the servo manufacturer, except for the middle hexagon
01:59 GargantuaSauce which is just a sheet cut&folded
01:59 totic that is so nice
01:59 totic and the software in the laptop is written in what?
02:00 GargantuaSauce C++
02:00 totic that is very nice
02:00 totic how long did it take you?
02:00 GargantuaSauce a year or so, on and off
02:01 GargantuaSauce maybe 200 hours of work in total
02:02 totic hardest part?
02:02 GargantuaSauce wireless comms maybe
02:03 totic really? ehm odd
02:03 GargantuaSauce i halfassed it super hard for that implementation, still procrastinating on making a proper general protocol
02:03 GargantuaSauce only really "hard" in the sense that i am making an excellent mountain out of that molehill
02:04 totic my problem with building things like that for me is that I know that as soon as I am done they go to a corner and thats it
02:04 GargantuaSauce i dont think this project will ever be "done"
02:04 GargantuaSauce there's always room for major improvement
02:05 GargantuaSauce generalized wireless protocol, a proper pcb instead of a disgusting perfboard, actual onboard control (i moved it offboard when i switched to 24dof and didn't bother moving back)
02:05 GargantuaSauce making real servos that arent garbage RC ones
02:05 GargantuaSauce etc
02:06 GargantuaSauce you can see my code here if you want https://bitbucket.org/Ultrasauce/robots/src
02:07 totic very clean code
02:07 totic so what do you do for work?
02:08 GargantuaSauce software, usually involving wrangling video in realtime
02:08 GargantuaSauce or webby bullshit
02:11 totic I think all software engineers at some point have done webby bullshit
02:11 GargantuaSauce hateoas gonna hate
02:12 totic its so annoying I have jury duty tomorrow..I mean today in 7 hours
02:16 GargantuaSauce oh i guess i should show you the earlier 18dof version too, http://www.youtube.com/watch?v=bj9gFFyR3-Y
02:16 GargantuaSauce same electronics
02:18 totic are those pencils?
02:18 GargantuaSauce yeppers
02:19 totic haha did you get it to paint/write anything interesting?
02:19 GargantuaSauce no they're upside down
02:19 totic it would have been hilarious if it just ran towards white areas signed them and the walked away
02:19 GargantuaSauce for the optimal grip and shock absorbance of the erasers
02:19 GargantuaSauce making anything legible with that pile of garbage would be quite a task
02:20 totic you just need one of the legs to be a bi tore dextrous
02:21 GargantuaSauce i could probably pull it off with the new design
02:21 GargantuaSauce with a sharpie and big letters
02:22 GargantuaSauce okay i added that to my ever-expanding list of stuff to do when i am less lazy
02:23 totic hahah
02:23 totic what else is in the list? some propellers? a scorpion tail?
02:23 GargantuaSauce oh encompasses well over a dozen completely different projects
02:24 GargantuaSauce lifetimes worth of work
02:25 GargantuaSauce i plan on doing some really fancy control stuff on it eventually
02:25 GargantuaSauce vision SLAM, etc
02:29 totic oh I have done slam
02:29 totic with a lidar
02:29 GargantuaSauce sweet
02:29 totic they are expensive though
02:30 GargantuaSauce yeah which is why i'm going to do it using cheapass cameras
02:31 totic or a kinect :)
02:31 GargantuaSauce cheating
02:31 GargantuaSauce probably going to start by just projecting a laser line parallel to the camera's line of sight
02:31 GargantuaSauce and using the parallax to determine depth along that line
02:32 GargantuaSauce and then move onto the fancier CV stuff like feature extraction
02:32 totic for that you are going to need a real processor
02:33 GargantuaSauce yeah i have an allwinner a10 board, hoping that will suffice to start
02:33 GargantuaSauce if not i dunno
02:33 GargantuaSauce those new steamboxes are ridiculously small and have fucking i7's in them!
02:34 GargantuaSauce sounds pretty useful for embedded shenanigans
02:34 totic yeah the cpu is not the real problem now days
02:34 totic its the graphics card
02:34 totic (for games at least)
02:35 GargantuaSauce well apparently the current generation of intel onboard gpus are passable
02:36 GargantuaSauce it is tempting to scale up enough to be able to jam a real gpu in there though
02:37 GargantuaSauce and do gpgpu nonsense onboard
02:37 GargantuaSauce that idea makes me pretty hard
02:37 totic game companies have gotten much better at letting everybody play the games at much "graphic levels"
02:38 GargantuaSauce yeah since even the 8 year old garbage is still pretty ridiculously powerful in an absolute sense
02:38 totic fuck just think about how powerful your phone is compared to your machine of 6 years ago
02:39 GargantuaSauce not quite, i have a terrible phone and built an awesome pc in 07
02:39 GargantuaSauce but yes the point stands
02:40 GargantuaSauce i do fantasize about going back in time a decade and telling myself that i built a 16tb nas
02:41 totic damn
02:41 totic what do you need that for?
02:42 GargantuaSauce need is one of those really powerful words that probably doesn't apply
02:42 totic maybe your past sell will assume somehow you became a billionaire
02:43 GargantuaSauce anyway i just like torrenting
02:43 GargantuaSauce and hoarding the results
02:43 GargantuaSauce anime, movies, music
02:43 totic I used to do that and then I realized I never went back to see the again
02:44 totic I did download 75 GB of music of this one server in the media lab
02:44 GargantuaSauce i don't game anymore but there's still a good number of disk images kicking around
02:44 totic and that has serve as the base of most of my music
02:44 Jak_o_Shadows I have a small media server. Probably 1.5TB?
02:44 Jak_o_Shadows Weird mix of HDDs, and it needs and update
02:45 totic between Netflix, Hulu and Amazon Prime + illegal streams I am pretty much set
02:45 Jak_o_Shadows Hmm, Netflix (NOPE), Hulu (NOPE), Amazon Prime (NOPE)
02:45 GargantuaSauce i like having stuff in 1080p
02:45 GargantuaSauce working with video has made me intolerant of compression artefacts
02:45 totic haha
02:46 Jak_o_Shadows I stream through DLNA to a TV, so it really needs to be 1080p
02:46 totic same reason why I never really want to learn about wines
02:47 GargantuaSauce http://www.gigabyte.com/products/product-page.aspx?pid=4888
02:47 GargantuaSauce this thing is about as big as a damn ATX power supply
02:48 Jak_o_Shadows Oooh yeah, that'd be cool.
02:48 totic it is quite nice
02:48 totic price?
02:49 GargantuaSauce $550ish i guess
02:49 GargantuaSauce oh, 650 for the 4770R
02:50 totic actually I don't need another machine
02:50 GargantuaSauce there you go using that word again
02:50 totic have 4 laptops at home
02:50 totic 2 ipads
02:50 totic 7 tablets
02:50 totic like 8 phones
02:50 totic (all paid by companies)
02:50 totic not me
02:52 GargantuaSauce so i take it you do mobile dev
02:53 totic I did in the past
02:53 totic I sort of fell into it by chance
02:53 totic was doing research for Nokia, then Telefonica
02:53 totic and then they just kept offering me jobs on it
02:53 totic but I worked for 7 years doing NLP and ML
02:54 Jak_o_Shadows What's the nicest mobile dev platform you've used?
02:54 Jak_o_Shadows and where does android rank
02:54 totic Android is great, hell compared to the shit nokia had .. jesus
02:55 totic IOS is good, but I hate their market system
02:55 totic were Apple has to approve you
02:55 totic never did blackberry or windows
02:55 Jak_o_Shadows haha
02:55 totic its a pity that Nokia went the way they did
02:56 totic imagine how good they would be running Android
02:56 totic they made amazing hardware, terrible software
03:02 Jak_o_Shadows The Lumias, etc, look nice, but not-android
03:05 joga I haven't really devved for it but maemo is very nice for being basically linux pc in pocket
03:05 joga so instead of looking for specific apps you can just write plain bash scripts to control the phone etc
03:06 Jak_o_Shadows A pity you know, nobody uses it.
03:07 joga heh, I've been using it for four years or so and will get another n900 today for backup :)
03:07 joga but yeah, forgotten it is
03:19 totic I have a N700
03:19 totic it was very slow
03:19 totic but it was a nice little concept
03:23 joga I've an n800 also, the screen is pretty nice etc but it only has wifi built-in so not very useful these days
03:24 joga I configured it to be a skype phone but haven't really used it in a long time
07:29 Tom_L http://www.electronicproducts.com/Computer_Peripherals/Communication_Peripherals/The_most_high-tech_business_card_you_ve_ever_seen.aspx
09:08 rue_house there are been fancier