#robotics Logs
Apr 01 2017
#robotics Calendar
12:02 AM Jak_o_Shadows: It's quite clever
12:05 AM Jak_o_Shadows: I remember seeing a guy use a mux ship like that to set the device address
12:05 AM rue_house: it is a i2c mux
12:05 AM Jak_o_Shadows: you'd have heaer pins to set it
12:05 AM rue_house: but you tell the mux whcih busses to activate
12:05 AM rue_house: you can activate them all at once if you want
12:05 AM rue_house: china wants about $2.50usd for them
12:20 AM rue_house: huh, it seems were the only people left on the planet that use cat3 telephone systems
12:23 AM Jak_o_Shadows: Who'se "were" Pretty sure I hav some of that at home
12:23 AM Jak_o_Shadows: probably dont' call it cat3 though
12:28 AM rue_house: closest word in china is telecom
12:29 AM * Tom_L still uses a can/string comm system
12:54 AM rue_shop3: canstring, is the can for canadian?
05:02 AM Snert_ is now known as Snert
05:37 AM pokmo: i have a small problem. the pinion (with a 50T mounted on it) and the output shaft (with a 16T) have a 1cm gap in between. does anyone know of a good way to have them connected?
05:38 AM pokmo: would it be a good idea to have another gear in between, to fill the gap?
05:49 AM Jak_o_Shadows: Not unless you have to
05:49 AM Jak_o_Shadows: More gears = more compliacted
05:49 AM Jak_o_Shadows: Plus, it'll reverse the direction
05:49 AM Jak_o_Shadows: Mostly it'll just complicate things.
05:51 AM robopal: pokmo, metal or plastic gears?
05:51 AM pokmo: robopal, they're plastic
05:51 AM pokmo: Jak_o_Shadows, yeah, that's what i thought
05:52 AM pokmo: but what might be a better way to transmit power across a gap
05:52 AM pokmo: a linkage?
05:53 AM robopal: can you show a photo, how large are they? diameter?
05:54 AM pokmo: robopal, they're module 0.6
05:54 AM robopal: I dont know what that means
05:56 AM pokmo: i'm only starting to design in cad at the moment. this image might not be very useful http://i.imgur.com/oQo2jp0.png
05:57 AM robopal: ehm
05:58 AM robopal: move closer the servo horn, extend the supports
05:59 AM robopal: linear, easy
06:00 AM pokmo: robopal, i know. but i can't. basically the positions of the 16T and the servo are fixed
06:12 AM robopal: http://imgur.com/a/lIIuY
06:15 AM robopal: are you going to 3d print the pinion?
06:15 AM pokmo: robopal, hmm but then the teeth wouldn't rotate in circular motion, right?
06:15 AM pokmo: robopal, yeah
06:15 AM robopal: the center of rotation doesnt change
06:16 AM robopal: you just extend the "horn" larger diameter
06:17 AM robopal: then you can make it any shape you like
06:17 AM pokmo: robopal, oh
06:17 AM pokmo: well, it's like my other idea actually
06:17 AM pokmo: i was just going to print a (partial) gear that's got more teeth
06:17 AM pokmo: like 64T rather than 40T
06:18 AM pokmo: that way i'll keep the gear specs consistent
06:20 AM robopal: simpler the better
06:22 AM pokmo: true
06:23 AM pokmo: but what complications might there be if the drive contains more gears?
11:09 AM mun: anyone know how this "prop shaft" is mean to be used? http://www.ebay.com/itm/stainless-steel-6-35mm-1-4-034-prop-shaft-for-square-end-1-4-034-flex-cable-rc-boat-/140667195052
11:09 AM mun: what are the two dents for?
11:21 AM robopal: for a set screw?
11:21 AM robopal: dont know
11:31 AM Tom_L: the square drive is for a flex shaft drive
11:31 AM Tom_L: the other end is for set screws
11:31 AM Tom_L: raced boats for years and never ever ever saw or used one
11:36 AM Tom_L: https://www.amainhobbies.com/pro-boat-flex-shaft-prb4258/p209392?gclid=CPqVzNbRg9MCFYuIaQodClICYA
12:35 PM rue_bed: weed eater?
12:35 PM rue_bed: mmm 10aM
12:36 PM rue_bed: fsk
12:36 PM rue_bed: hmmm
12:36 PM rue_bed: pam
12:56 PM rue_bed: the langage isn't well seperated between the parameters of a pulse and the modulation of a pulse stream
08:02 PM Jak_o_Shadows: What are you working on rue?
09:37 PM rue_house: arm10
09:37 PM rue_house: fitting the pullies
09:37 PM rue_house: and putting the wrist on
09:37 PM rue_house: I'm gonna need to properly attach the forearm soon
09:37 PM rue_house: the gravity connection I'm using wont hold up to proper use
09:38 PM Tom_L: hmm up to 10 already?
09:38 PM rue_house: yep
09:38 PM zhanx: rue_house: I got a 3rd printer today
09:38 PM Tom_L: how many sacrifices were made to 10
09:38 PM zhanx: now i have xyz
09:38 PM rue_house: not all small ones, it goes from the first one I ever made
09:38 PM zhanx: axis
09:38 PM rue_house: about 6 dont currently exist I think
09:38 PM rue_house: well
09:38 PM rue_house: arm 7, 8, 9 are the small ones
09:39 PM rue_house: arm5 iirc is the stepper based one
09:39 PM Tom_L: dammit, i can't find a function i want to use
09:39 PM rue_house: and 6 is the huge one
09:39 PM Tom_L: i know it's there, i saw it
09:39 PM Tom_L: and i wrote one to do the same thing but would rather use the function
09:40 PM Tom_L: to create a 'demo' exe
09:40 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm1/432-arm1.jpg arm1, highschool project, dosn't currently exist assembled
09:40 PM rue_house: arm2, no images
09:42 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm3/p1000723.jpg arm3, design didn't work, got taken apart to make a different one
09:42 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm4/p1060581.jpg arm4, stepper based, still exists
09:42 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm5/p1030984.jpg arm5 isn currently taking up 1/4 of the main workbench
09:43 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm6/p1070897.jpg arm6 is that one that is using parts from arm3
09:44 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm7/p1060364.jpg arm7 still exists, first of the hobby servo arms
09:44 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm8/p1060648.jpg arm8, the improvement of arm7
09:44 PM rue_house: http://ruemohr.org/~ircjunk/robots/arm9/p1060859.jpg arm9 the improvement of arm8
09:45 PM rue_house: and arm10 is the improvement of arm9 with some 3d printed and some cnc parts
09:46 PM zhanx: rue_house: ignores me saying yes 3d wax printer, got 3 printers to make out of
09:51 PM Jak_o_Shadows: Could ARM5 feasibly hold a monitor? When it's off?
10:04 PM Jak_o_Shadows: Or when it's on for that matter
10:05 PM rue_shop3: zhanx, what am I ignoring?
10:05 PM zhanx: 3d wax printer for casting
10:05 PM rue_shop3: Jak_o_Shadows, arm5's actuators are 8000nm
10:05 PM rue_shop3: right
10:05 PM rue_shop3: you dont want to?
10:05 PM zhanx: no i said yes
10:06 PM Jak_o_Shadows: 8 kNm? So that's a yes? Get it to hold a screen, and just follow you
10:07 PM Jak_o_Shadows: Unless it's nosiy
10:08 PM Anniepoo_: zhanx, nice!
10:08 PM Anniepoo_: how big a nozzle will you use?
10:08 PM Anniepoo_: now I see your interest in our casting
10:09 PM rue_shop3: sorry 8000N
10:09 PM rue_shop3: anniepoo, I'm thinking standard 0.3mm
10:10 PM zhanx: same here
10:10 PM zhanx: .3mm
10:10 PM Jak_o_Shadows: 8000N is a LOT more than I weight! So still a yes :P
10:10 PM Anniepoo_: investment molding is often associated with small parts, why I ask
10:11 PM zhanx: well i want to make robot parts etc
10:12 PM Jak_o_Shadows: What temp is that at?
10:12 PM Anniepoo_: makes sense
10:13 PM Anniepoo_: well, we should collaborate
10:13 PM Anniepoo_: I have a CNC router, home made by somebody else, that could be converted
10:18 PM Anniepoo_: Jak, are you asking me or zhanx?
10:19 PM Jak_o_Shadows: erm. Anyone about the wax 3d printing
10:19 PM rue_house: need to come up with a special wax extruder
10:20 PM rue_house: that preheats the wax to make it operable before it hits the head
10:20 PM zhanx: the temp i dont know yet
10:20 PM rue_house: there is a sugar printer that some bio geeks have been using to make ears and stuff that might have a plausable design
10:20 PM Anniepoo_: the temp's fairly low
10:20 PM rue_house: yea
10:20 PM rue_house: under 100c
10:21 PM zhanx: with lots of fans to cool it fast
10:21 PM rue_house: not if you dont heat it up too much
10:21 PM Anniepoo_: it depends on the wax - most casting waxes are over 100C
10:21 PM rue_house: extrude it thick
10:21 PM rue_house: candle was ist cheap ja
10:21 PM zhanx: yea
10:21 PM Anniepoo_: yes, in fact that's what we're using
10:21 PM Anniepoo_: for our first run
10:22 PM Anniepoo_: but candles have their own issues
10:22 PM rue_house: go to the 2nd hand store and buy all the ugly candles nobody wants
10:22 PM rue_house: yea, have go get rid of the string
10:22 PM Anniepoo_: the higher the temp, the less issues with cooling time
10:22 PM rue_house: it burns out if your patient :)
10:22 PM Anniepoo_: and the more detail
10:23 PM Jak_o_Shadows: I COULD change to have 64 byte tx and rx, instead of the 1 byte at a time I was using with usart.
10:23 PM Jak_o_Shadows: Or I could update the TX to get speed, and ignore RX
10:23 PM Jak_o_Shadows: I'd have to redo my communications state machine, and I aint bothered with that
10:23 PM rue_house: but then byte sync is an issue
10:24 PM Jak_o_Shadows: ?
10:24 PM rue_house: is the state machie C?
10:24 PM rue_house: have I seen in before?
10:24 PM Jak_o_Shadows: No, you haven't seen it.
10:24 PM Jak_o_Shadows: It's due a rewrite, but that's not a priority
10:25 PM zhanx: anniepoo: I want to cast hollow parts that should be fun
10:25 PM Anniepoo_: remember you have to get the investment out,
10:26 PM zhanx: yep
10:26 PM Anniepoo_: but we're doing dog collar buckles, like the snap buckles on camping gear and butt bags
10:27 PM zhanx: i want super thin walls but i know my casting sucks right now
10:28 PM Anniepoo_: I've seen suprisingly thin investment cast walls
10:28 PM zhanx: well 3 print is first and then shrink them as i get bettter
10:29 PM zhanx: robot frame
10:29 PM zhanx: inspired by bird bones
10:29 PM Anniepoo_: at some trade show a place was showing off a small cylinder & head, about 1" dia, like for a tiny gas motor, with walls that were basically sheet metal, maybe 20 mil
10:31 PM zhanx: nice
10:33 PM Anniepoo_: I have a casting pro working for me, he's teaching me this stuff
10:33 PM Anniepoo_: I'll ask him about making thin wall castings
10:40 PM zhanx: that would help
10:43 PM Anniepoo_: hey even better for you -
10:43 PM Anniepoo_: turns out you can burn out PLA
10:44 PM Anniepoo_: I don't have a 3D printer. If you'd make a test print in PLA and send it, we'd test cast it just to see how practical this is.
10:45 PM rue_shop3: not burning out pla
10:45 PM Anniepoo_: ??
10:45 PM Anniepoo_: why not?
10:45 PM rue_shop3: expensive, messy, and not effective
10:46 PM Anniepoo_: styrene's pretty routinely done this way
10:46 PM Anniepoo_: with small one-offs, eg of small mechanism parts, that aren't conveniently made in wax
10:49 PM zhanx: anniepoo: I want to make a 8 foot humanoid frame like this
10:50 PM Anniepoo_: thats more appropriately a green sand casting
10:50 PM Anniepoo_: hmm... you could make a green sand printer
10:51 PM zhanx: well ( need to research green sand) this is gonna be small interlocking parts
10:52 PM Anniepoo_: ah, lots of small parts, yes, investment
10:52 PM zhanx: hence the wax and investment style cast and clean them up later
10:52 PM Anniepoo_: there's a weird gel molding process that might be best
10:52 PM Anniepoo_: hang on
10:54 PM Anniepoo_: https://en.wikipedia.org/wiki/Shell_molding
10:54 PM Anniepoo_: 8cD
10:54 PM Anniepoo_: it's a more complex process
10:55 PM Anniepoo_: but might be less grief in the end
11:01 PM rue_house: !!!!!
11:01 PM rue_house: if I have cheese, and bread, I could make a toasted cheese sandwhich
11:02 PM rue_house: zhanx, green sand:
11:02 PM rue_house: make a ball mill (rock tumbler)
11:02 PM rue_house: find bentonite kitty litter
11:02 PM rue_house: grind to a fine powder
11:02 PM rue_house: get fine sand
11:03 PM rue_house: add some of the bentonite powder, add a BIT of water, mix till it will clump in your hand without breaking apart, and otherwise snap cleanly in half
11:03 PM rue_house: waste sand from a sand blaster is ideal (the stuff from the vacuum)
11:06 PM Anniepoo_: oooh
11:06 PM * Anniepoo_ is impressed at breadth f Rue's makertude
11:07 PM Anniepoo_: robotics is an area where it's easy to talk instead of acutally doing. I have a productivity trick I use for work, it might apply here as well
11:08 PM Anniepoo_: and Rue's just motivated me to go actually do something instead of laying in bed watching youtube and twitter and such
11:08 PM Anniepoo_: which is what I'm doing
11:08 PM Anniepoo_: Soo....
11:08 PM Anniepoo_: my 'trick' is called 'hours'
11:09 PM rue_house: start by making a rock tumbler :)
11:09 PM Anniepoo_: it's real simple. You find one or more 'hours partners'
11:09 PM Anniepoo_: have a rock tumbler
11:09 PM rue_house: perfect
11:09 PM rue_house: find steel balls or some rocks for it
11:09 PM Anniepoo_: even have bentonite based kitty litter that's gone thru it
11:09 PM rue_house: maybe 1/3 1/4 volume
11:10 PM rue_house: ah
11:10 PM Anniepoo_: yah, I have lead and steel balls
11:10 PM * rue_house crosses his legs
11:10 PM Anniepoo_: anyway, so, productivity trick -
11:11 PM * Anniepoo_ . o O ( add brass balls to stuff we should have in stock )
11:11 PM Anniepoo_: all the hours partners say what the'll do in next hour
11:11 PM rue_house: 'hours partners' waiting on details
11:11 PM Anniepoo_: and in an hour we check in
11:11 PM Anniepoo_: just say what we actually accomplished
11:12 PM rue_house: ah
11:12 PM rue_house: I need a shop cam that can post directly to internet without all the SD card/ etc junk
11:12 PM rue_house: usb direct or wifi or something
11:12 PM Anniepoo_: ok, are you gonna wire that up in next hour?
11:12 PM Anniepoo_: 8cD
11:13 PM rue_house: dont have any parts ot use to make it
11:13 PM rue_house: well, I have a capture card, but 640x480 sucks
11:13 PM Anniepoo_: ok, well, in the next hour I'll get my lazy butt outta the house, over to the shop, and get started on making a second attempt at cutting cardboard mockup of snaily
11:14 PM rue_house: 2nd?
11:14 PM rue_house: :/ im out of cheese
11:14 PM Anniepoo_: yah, first one had some software problems only obvious after cutting all the parts
11:14 PM Jak_o_Shadows: Funnily enough, I am working on usb camera
11:14 PM rue_house: the meal that took me 1hr to cook was eaten in like 9 mins
11:14 PM Jak_o_Shadows: Just quickly
11:14 PM Anniepoo_: anybody else gonna do this?
11:14 PM rue_house: Jak_o_Shadows, made with?
11:15 PM Anniepoo_: hey Jak, you into this?
11:15 PM Jak_o_Shadows: A STM32F429i discovery board (so a cortex M4), and a mt9m001 camera
11:15 PM rue_house: my big cnc is 6"x11"
11:15 PM rue_house: er, 5.5 x 11"
11:15 PM Jak_o_Shadows: Anniepoo_, I don't have internet in the shed, and besides, I think we're in different timezones
11:15 PM rue_house: it was supposed to be 6x12, I blew the overhead
11:15 PM Anniepoo_: ok
11:16 PM Anniepoo_: rue, you in?
11:16 PM rue_house: for?
11:16 PM Jak_o_Shadows: Problem with this code rue is that it's not pretending to be a webcam.
11:16 PM Anniepoo_: hous
11:16 PM Anniepoo_: hours
11:16 PM rue_house: k
11:16 PM Jak_o_Shadows: On the other hand, the camera bit could post directly to serial, so it could go to an esp
11:16 PM Anniepoo_: what're you doing?
11:16 PM rue_house: its 8:47pm now, I'm gonna be up till 1am
11:16 PM Anniepoo_: ok, I'm likely to be up late
11:17 PM Anniepoo_: so, what are you doing in *next hour?*
11:17 PM rue_house: I'm resnting not having used 2 pans to make a descent volume of hashbowns
11:17 PM rue_house: right now, my cnc is going up and down
11:17 PM rue_house: as fast as it can
11:17 PM Anniepoo_: ok
11:17 PM rue_house: its jogging in the new z sliders
11:17 PM rue_house: then I should have it make something
11:18 PM Anniepoo_: how long do you have til it finishes wearing in?
11:18 PM Anniepoo_: Xc[
11:18 PM rue_house: hmm, interesting point, at what point is it not wearing in, and wearing out?
11:18 PM rue_house: I could check on it now
11:19 PM Anniepoo_: sigh...
11:19 PM rue_house: ?
11:19 PM rue_house: your looking for a 1 hour goal, right?
11:19 PM Anniepoo_: yes
11:19 PM Anniepoo_: 8cD
11:19 PM rue_house: ok, processing...
11:19 PM rue_house: ok, might be tight, but mouting the tripper to arm10
11:20 PM rue_house: no, reverse
11:20 PM rue_house: making a image web page collection for arm10
11:20 PM rue_house: yes, I'll make the folder and post the images of arm10
11:20 PM Anniepoo_: ok, cool
11:20 PM rue_house: and start supper2.0
11:20 PM Anniepoo_: I find it works best to be conservative
11:20 PM Anniepoo_: 8cD
11:21 PM Anniepoo_: so, I'm going to get to shop and get individual parts exported to run thru 123D make
11:21 PM Anniepoo_: startin at 51 mins after hour, I'll be back on in 15 or so
11:22 PM Jak_o_Shadows: I should try to to reflash that mini router with english firmware
11:28 PM anniepoo: cool
11:38 PM rue_house: supper started, visitor dealt with, axe cleaned, what was I doing?
11:38 PM rue_house: ok
11:44 PM rue_shop3: oh yea
11:46 PM anniepoo: 8cD why this is useful
11:46 PM anniepoo: I'm at the shop, just in middle of exporting data in form laserworks can read
11:51 PM rue_shop3: I created the dir, and made the script to upload to it