#robotics Logs

Mar 06 2018

01:11 AM zhanx__ is now known as zhanx
03:26 AM veverak: rue_bed: have you ever printed PETG? is it necessary to dry it?
07:06 AM Atomsk is now known as ace4016
09:12 AM rue_: nope
09:12 AM rue_: mostly pla, tried abs
09:13 AM robotustra: morning
09:15 AM rue_: morning
09:15 AM rue_: new 3d printer is working nicely
09:15 AM robotustra: what the progress?
09:15 AM robotustra: what model?
09:15 AM dravine: howdy all
09:16 AM robotustra: good
09:16 AM robotustra: rue_, delta or xyz?
09:16 AM rue_: http://ruemohr.org/~ircjunk/images/pi/IMG04Mar2018_064205.jpg
09:16 AM robotustra: hm
09:17 AM robotustra: reprap
09:17 AM robotustra: built from sticks and walnuts
09:18 AM rue_: and printing awesome
09:18 AM robotustra: I finally attached the t-slotted table to my cncn mill, but didn't try it yet
09:18 AM robotustra: next step is to install mist
09:19 AM rue_: http://ruemohr.org/~ircjunk/images/pi/IMG04Mar2018_044116.jpg
09:19 AM rue_: the PI auto-posting-to-webpage camera is working nice too
09:20 AM robotustra: what is the sizes?
09:20 AM robotustra: is it M8 or M10?
09:20 AM rue_: printer?
09:20 AM robotustra: yeah
09:20 AM rue_: the frame is 5/16 and the z is M8-1
09:21 AM rue_: rails are 8mm
09:21 AM rue_: didn't bother upsizing them on this
09:21 AM robotustra: this model is easily scalable
09:21 AM rue_: BUT
09:21 AM rue_: I'm probably going to change the z to a belt on this one
09:21 AM rue_: I have some geared steppers to do it with
09:21 AM robotustra: why?
09:21 AM rue_: no z wobble
09:22 AM robotustra: why to remake something if it works?
09:23 AM rue_: it dosn't
09:23 AM robotustra: ah ok
09:23 AM rue_: I get wobble in all my prints
09:23 AM rue_: I spent 4 hours on the couplers for that one, and the rod isn't straight
09:23 AM rue_: you cant win
09:23 AM robotustra: so, the rpinter does not work GOOD
09:24 AM rue_: for 20 years I been trying to couple threaded rod to motors, it never works
09:24 AM rue_: always wobble
09:24 AM rue_: robotustra, fair enough, but yea
09:24 AM AchiestDragon: bearing at each end of threaded rod with flexible motor couplings
09:24 AM rue_: no
09:25 AM rue_: the rod isn't straight
09:25 AM rue_: its twisted
09:25 AM rue_: S
09:25 AM rue_: spiral
09:25 AM robotustra: there is an answer: ACME
09:25 AM rue_: and the threads aren't centered in its dia
09:26 AM AchiestDragon: theres the problem you need rod that is straght and not twisted
09:26 AM rue_: OR I can just use a belt drive
09:26 AM robotustra: there is 1 more option
09:26 AM rue_: antigravity? those are expensive too
09:26 AM robotustra: smooth rod + 3 bearings
09:27 AM rue_: I dont think you can get positive traction with that tho
09:28 AM AchiestDragon: get a tap , and die set for the size you want and thread it yourself using straight bar , the results are better if you take your time
09:28 AM rue_: I modified some peices, I'm gonna play with a Z belt drive
09:28 AM rue_: dude __20 years__ of trying to get threaded rod on a motor straight
09:28 AM rue_: lots of lathe work
09:28 AM rue_: no success
09:29 AM AchiestDragon: if you buy threaded bar thats made from soft steel then the chances are its rough and bent , ot had the same prob with A2 stainless steel threaded bar
09:29 AM AchiestDragon: ot / not
09:29 AM rue_: yes, I could spend a lot of money for ground acme OR use belt drive
09:29 AM rue_: the machines cork screw it as they make it
09:30 AM robotustra: ok, do the belt
09:30 AM rue_: my vote is belt drive
09:30 AM robotustra: topic is closed
09:30 AM rue_: I'll tell ya how it turns out
09:31 AM robotustra: belts are good
09:31 AM rue_: I have some 18:1 stepper motors
09:31 AM AchiestDragon: alot of the cheap threaded bar is threded in one cut , that can twist the bar , you need to have a die that you can adjust and thread it in 2 to 3 passes till the depth of thread is right , then theres less stress on the bar
09:32 AM robotustra: I'm planning to make a mist+blower and then try to flaten a bit the bars before scraping it
09:32 AM rue_: I think the only reason the z wasn't belt drive in the first place was cuase it couldn't be done direct drive
09:33 AM rue_: the X and Y shouldn't be direct either, I did mine 2:1 with awesome results
09:33 AM robotustra: it's not servos?
09:33 AM rue_: :( no
09:33 AM rue_: one day!
09:34 AM robotustra: I played with servos a little bit - they are cool
09:34 AM rue_: but I have 3 creates of stepper motors I'd like to partly use up
09:34 AM rue_: crates
09:34 AM robotustra: you can do you r own servo btw
09:34 AM rue_: I kow
09:34 AM rue_: I have some great atmega32 code
09:36 AM robotustra: https://www.youtube.com/watch?v=CIRKRzw54Zs
09:37 AM robotustra: good idea
09:37 AM robotustra: optical mouse as a feedback
09:37 AM rue_: not neccissarily
09:38 AM rue_: they can slip
09:38 AM robotustra: yes
09:38 AM rue_: old mice had useless max speeds and acceleration stuff in them
09:38 AM robotustra: rotary encoder?
09:39 AM rue_: tho, the results of that vid look pretty good
09:39 AM robotustra: https://www.youtube.com/watch?v=v2jpnyKPH64
09:39 AM rue_: the problem used to be the chips
09:41 AM robotustra: here is the cheap solution
09:41 AM robotustra: a disk with optics sensor and regulator
09:45 AM robotustra: rue_, this guy homoFacien also likes to build from sticks and cheap shit
09:46 AM rue_: if you have money to burn I'm glad for ya
09:49 AM robotustra: rue_, don't tell me that you don't have money for hobby
09:51 AM robotustra: rue_, if you don't have money for hobbby and still doing the hobby - it might be a stessful for you
09:51 AM rue_: I dont spend $1600 on one project, I spend $1600 over 80 projects
09:51 AM rue_: more usually, I rarely spend the whole $20 for a project
09:51 AM rue_: pretty sure that last printer was barely that
09:51 AM AchiestDragon: slotted opto sensor , and a 3d printed encoder disk , if the slotted senosr is too much try a ir phototransistor and led (you could use one from a old ball type mouse if you have one with optical encoders rather than contacts )
09:52 AM rue_: how about an etched aluminum foil disk?
09:52 AM robotustra: rue_, ok, you have a reason
09:52 AM rue_: photoetched using UV nail polish as a etch resist?
09:52 AM robotustra: I prefer bigger long term projects
09:53 AM robotustra: use laser printer toner as a mask
09:53 AM rue_: yea, I do lots of projects and learn a lot from them
09:53 AM dravine: rue_ you can just buy those as stickers
09:53 AM dravine: https://www.zazzle.com/8_bit_gray_code_rotary_encoder_classic_round_sticker-217079996057094596
09:53 AM rue_: I can get better esolution with a photomask
09:53 AM rue_: !?
09:53 AM robotustra: I would print on a laser printer
09:54 AM rue_: not a real photo of it
09:54 AM rue_: you know about bushytails encoder generator right?
09:54 AM robotustra: no
09:55 AM robotustra: what is bushytails
09:55 AM robotustra: optical stuff?
09:55 AM robotustra: a disk with slots?
09:55 AM rue_: no, just a person
09:55 AM AchiestDragon: or use a toothed gear with a proximaty sensor like they do for abs , no problems with bright lights or flash guns affecting it then
09:55 AM robotustra: ah
09:56 AM rue_: http://www.bushytails.net/~randyg/encoder/encoderwheel.html
09:56 AM rue_: we raced to make it and he won
09:56 AM rue_: I'm not done yet
09:56 AM robotustra: rue_, ah, ok
09:56 AM rue_: been about 16 years
09:57 AM rue_: "subject died on start line"
09:57 AM robotustra: you can read the value directly from encoder
09:57 AM rue_: you can make those with that
09:57 AM robotustra: in binary format
09:57 AM rue_: yea
09:57 AM rue_: you can make those with that
09:57 AM rue_: it requires reading and typing in values
09:57 AM robotustra: the absolute angle
09:58 AM rue_: yea you can
09:58 AM rue_: you can makea _9_ bit one! ooooooo
09:58 AM robotustra: may be I borrow this idea for my robot
09:58 AM robotustra: to count rotations
09:59 AM rue_: http://ruemohr.org/~ircjunk/images/pi/
09:59 AM rue_: watch for a new image in a min, I'll take a pic of what I been working on
10:02 AM robotustra: I see 3d printer
10:05 AM rue_shop4: _last_ iamge
10:05 AM rue_shop4: did it work
10:05 AM rue_shop4: I didn't stand in the way did I?
10:06 AM rue_shop4: more or less, last two images
10:06 AM robotustra: too many objects on the image
10:06 AM rue_shop4: WHEN THE PARTS ARRIVE FROM CHINA I'm going to solder them to the pcb inside
10:06 AM rue_shop4: robotustra, let me help you
10:06 AM robotustra: controller enclosure?
10:06 AM rue_shop4: http://ruemohr.org/~ircjunk/images/pi/IMG06Mar2018_160111.jpg
10:06 AM rue_shop4: http://ruemohr.org/~ircjunk/images/pi/IMG06Mar2018_160138.jpg
10:07 AM rue_shop4: those are the "last two" images in the dir, you can tell by the date on them :)
10:07 AM robotustra: ah, it's encoder
10:07 AM rue_shop4: of course, you have to click refresh on that page because your browser does not support update notification
10:08 AM rue_shop4: it will be, hopefully
10:08 AM robotustra: why do you use aluminum foil?
10:08 AM rue_shop4: cnc cut pcb
10:08 AM rue_shop4: thin, etch, resolution
10:08 AM robotustra: copper can work too
10:09 AM robotustra: do you have a pics of etched disk?
10:11 AM robotustra: or it's not fabricated yet?
10:12 AM rue_: had problems etching the aluminum
10:12 AM rue_: http://ruemohr.org/~ircjunk/images/pi/IMG06Mar2018_160830.jpg
10:12 AM rue_: nice little case so far tho
10:13 AM robotustra: https://www.youtube.com/watch?v=iGEdF5QsDB8
10:14 AM rue_: I wonder what operating that wouldbe like in a force feedback suit
10:15 AM rue_: ooo are those compliant joints?
10:16 AM robotustra: dont know
10:16 AM rue_: I better go now
10:16 AM robotustra: go
03:23 PM LuminaxWk is now known as Luminax
07:27 PM rue_: "er, sorry, I'm ok, that sentence reads different when I correctly read the word 'paid' instead of 'laid'... "