#robotics Logs

Feb 12 2014

00:03 rue_bed reprap heater, 12000W
00:03 rue_bed plastic measured in gpm
00:16 Fiesta i have a servo on a continuously rotating platform, the wires will just twist and twist, what do?
00:17 Fiesta do i connect to it with brushes or something?
00:17 Fiesta or is there a continuously rotating connector that will save me
00:17 Faek Commutator rings
00:17 Faek (ignore me)
00:18 dumbass-afk or put that servo's batteries on the platform with it
00:18 dumbass-afk (ignore me)
00:18 Fiesta uh, why is everyone saying "ignore me"?
00:19 rue_bed Fiesta, dont use continious rotation
00:19 rue_bed Fiesta, nobody regards themself as an authority
00:19 Faek Because i'm talking bullshit
00:19 dumbass-afk most engines use continuous rotation, rue
00:19 rue_bed (ignore me)
00:19 Fiesta it's a gimball, i'd rather have continuous rotation
00:19 dumbass-afk (ignore him)
00:19 rue_bed oooh
00:19 rue_bed yea, make the frame the wires
00:20 rue_bed Fiesta, your not making a motorized austronaut trainer are you?
00:20 dumbass-afk rue, gimball != gyroball
00:20 Fiesta no it's a pan/tilt for a sky-cam
00:20 Faek Cause if you are i want pictures
00:20 dumbass-afk or "hamster wheels"
00:21 rue_bed then dont use continious rotation servos
00:21 Fiesta it needs to be able to do that whole "bullet camera" matrix thing, so go around and around and around without break.
00:21 rue_bed no, at 360 degrees you go back around the long way to 0
00:21 Fiesta no
00:21 dumbass-afk then you need *all* the wires non-raveling
00:21 Fiesta just 3 wires
00:22 dumbass-afk video, camera power, servo power, servo drive signal, any feedback
00:22 Fiesta the only thing that's on the wrong end of the rotation is the tilt servo, just 3 wires.
00:22 dumbass-afk how are you not twisting camera power?
00:23 Fiesta there's a camera on that - but it's just a smartphone so it has it's own battery and connects via wifi
00:23 dumbass-afk ok, put a Lion battery along with the camera to power the servo
00:23 Fiesta the servo will need a controller
00:24 Fiesta i could add an extra arduino, but then that needs power and blksdjfl;askfjasdklfjsdfl;k
00:25 dumbass-afk pin up the hollow axis, bearing on top and bottom, servo below driving the lower bearing up/down, platform on top bearing being pushed up/down
00:25 Fiesta "Commutator rings" is a good lead i can look into, thx
00:25 mbass-afk points to rue's robot
00:28 rue_bed comming up with quite the rule list for hte mecha desgin
00:28 rue_bed shall I paste?
00:28 dumbass-afk 1) do not deploy the gattling guns to change light bulbs
00:29 rue_bed how about
00:29 rue_bed * NO STRUCTURAL PEICE SHALL BE MADE OF METAL THINNER THAN 200 THOU AND SHALL NOT BE GALVANIZED
00:29 Faek Haha
00:29 rue_bed * NO MORE THAN 3 WIRES IN THE SAME BUNDLE SHALL HAVE THE SAME COLOUR, UNLESS THEY ARE MEMBERS OF A GANGED, SINLGE CONDUCTOR, OR THE SAME NODE
00:30 dumbass-afk wait,, 200 thou is more than 1/8 inch
00:30 rue_bed yea
00:30 rue_bed these are all things that I'v found would have saved me a problem at some point in the past
00:31 rue_bed * ALL CONDUCTORS SHALL BE UNIQUELY LABELED WITH THEIR NODE NUMBER AND THE COLOUR OF THE WIRE THEY DESCRIPT, BOTH PIECES OF THIS INFORMATION MUST LIE ON SAME PHYSICAL PEICE OF THE LABEL
00:31 rue_bed cause in the end, all wires are black...
00:32 rue_bed * ALL WIRE MUST BE FINE STRAND.
00:32 rue_bed cause, solid wire on something that moves = bad idea
00:32 rue_bed * ANYTHING LARGE ENOUGH TO BE CLIMBED SHALL BE EQUIPPED WITH 4 POINT HANDHOLDS AND FOOTRESTS WITH GRITTED FINISH
00:32 dumbass-afk welding wire for heavy power, it's the most finely stranded of all power wires
00:33 rue_bed * ANYWHERE SMALL SCREWS ARE LOCATED THAT CAN BE READILY DROPPED AND LOST SHALL BE EQUIPPED WITH SPARE TAPPED HOLES SUCH TO HOLD SPARE SCREWS
00:33 rue_bed and, like, should be loaded up with spare screws...
00:34 rue_bed * LINES SMALLER THAN 1cm MUST BE CARRIED IN A PROTECTIVE SHEATH OF ATLEAST 1CM
00:34 Fiesta http://www.ebay.com.au/itm/White-Plastic-Housing-Rotating-RJ9-4P4C-Male-to-Female-Connector-Adapter-/161194525875 ah, this might work.
00:34 rue_bed I dont know how many projects now, little wires get caught in mechnics
00:34 dumbass-afk anything you can grab hold of when climbing up on it, shall be able to hold your weight
00:34 rue_bed use rj45, its more common
00:35 rue_bed and remember, when they turn there is a lot of electrical noise
00:35 Fiesta despondancy++
00:35 rue_bed kat, implied, but indeed
00:35 dumbass-afk sterio 1/4 phone jack and plug will give you 3 conductors
00:35 rue_bed the newest two are
00:35 Fiesta oh... OH!!!
00:35 Fiesta yesssss!
00:36 Fiesta perfect, thx dumbass
00:36 rue_bed kat, I forgot about that one, I used it on a windmill once
00:36 rue_bed * ALL FLUID SYSTEMS MUSE BE EQUIPPED WITH DRAINS.
00:36 rue_bed * ALL TANKS MUST BE EQUIPPED WITH DRAINS.
00:36 mbass-afk curt
00:36 rue_bed I took apart a hydraulic thing from the hospital on the weekend and there was no flipping drain, oil everywhere
00:36 dumbass-afk all tanks must have foolproof level guages and have pressure reliefs
00:37 rue_bed Fiesta, you can get them in 4 conductor too, if you wanted to run 2 servos (+- noise)
00:37 rue_bed oo
00:37 dumbass-afk oh, drain fittings shall be **HUGE**, water and oil froth in an air tank can stop up 1/4 drains and vents
00:38 dumbass-afk it's like flushing a home water heater thru a 1/2 faucet at te bottom, it just does not ever work
00:38 Fiesta the more the merrier, if i could conduct all of the USB lines plus the 3x servo lines that'd be perfect.
00:38 Fiesta coz then i could connect physically to the phone
00:39 Fiesta and maybe use it to power the arduino via USB-OTG (assuming that's how it works)
00:39 dumbass-afk ok, go back to slip rings: 1/2 dowel or cpvc pipe, make sleeves of 1/2 copper pipe (not tube)
00:39 dumbass-afk hold it all together with epoxy
00:40 e_bed shakes his head and mumbles "electrical no
00:40 dumbass-afk safety pins make good "brushes", or use spring steep packing strap (sand the varnish off it)
00:40 dumbass-afk steep/steel
00:40 Faek Don't mumble it, shout it. Get the point across!
00:40 Fiesta unfortunately i can't put the whole thing on the rotating platform because it's connected to 3 stepper motors, so many cables urgh
00:41 dumbass-afk how often does the thing run? cuple hrs/day? all day?
00:41 rue_bed I suppose the usb packet goes thru before it moves...
00:42 Fiesta there's no constrints on running time as yet, i'm trying to work out what's feasible first
00:43 dumbass-afk well, eventually the cell phone will die of low battery and you'll get the phone bill
00:43 Fiesta yeah
00:43 Fiesta oh it connects via wifi not cell towers
00:43 dumbass-afk k
00:44 dumbass-afk 1/4 phone, prolly last for years
00:44 Fiesta how many USB lines are there, 4?
00:45 dumbass-afk 6? dual balanced lines, pwr, gnd
00:45 dumbass-afk and shield, optional
00:46 Fiesta aright, so i guess i'd like 9 connectors on this rotating platform, oh boy.
00:46 dumbass-afk ouch
00:47 Fiesta i might look around for common types of connectors that have a lot of lines in them. i think you can get rotating usb, so that's 6, a start.
00:48 dumbass-afk what about IR for the signal lines?
00:48 Fiesta hey HDMI looks like it has a lot of lines in it, wonder if there's rotating connectors for that i can re-purpose.
00:48 dumbass-afk not at hdmi freqs
00:49 Fiesta i won't be using HDMI freqs, i'll just be using it as a handy source of conductance
00:50 dumbass-afk i understand, but they wouldn't make an hdmi swivel, because it wouldn't work ay hdmi freqs
00:50 Fiesta oh you mean HDMI won't have rotating connnectors, yeah maybe.
00:50 dumbass-afk be like using cat5 for welding cables
00:51 Fiesta i see some rotating HDMI connectors on ebay, but i dunno if they will rotate continuously.
00:52 mbass-afk gives up and whips out go
00:53 dumbass-afk https://duckduckgo.com/?q=%22copper+pipe%22+slip+rings+power+brushes
00:53 dumbass-afk you can get any carbon-copper brushes you could possibly need on ebay
00:55 Fiesta so.. maybe a stack of 9 slip rings
00:55 rue_bed just usb eh?
00:55 Fiesta usb + a servo
00:56 rue_bed heh, I cant wait to hear how this works out
00:56 Fiesta yeah it's getting a bit crazy
00:56 dumbass-afk http://www.carlpisaturo.com/_ElNo_SLIP.html
00:59 Fiesta excellent, there's slip rings on ebay, first ones i'm seeing have 6 wires, so this is quite hopeful
01:00 Fiesta 12 wire ones for ~$11, bam!
01:00 Fiesta problem solved
01:00 dumbass-afk good deal, with brushes?
01:01 Fiesta i assume so http://www.ebay.com.au/itm/Mini-Capsule-Slip-Ring-12-Wires-2A-500Rpm-U-Type-/160934530753
01:02 Fiesta i like how it it has a giant picture of a usb cable in the middle of the description for no reason
01:02 Fiesta i'll pay extra for that
01:03 dumbass-afk pics can't cost that much, even in Oz
01:04 mbass-afk finds the usa version of it on ebay : http://www.ebay.com/itm/160934530753
01:04 dumbass-afk yeow : Delivery:
01:04 dumbass-afk Estimated between Tue. Feb. 25 and Thu. Mar. 13
01:04 Fiesta yeah, china.
01:06 dumbass-afk i see not data sheets on it, the links to inkfrog don't work
01:07 dumbass-afk i am concerned the swivel is usb-usb
01:07 Fiesta i doubt it'll be ideal
01:08 dumbass-afk http://www.ebay.com/itm/12-2A-12-Wires-2A-12-Circuits-Compact-Slip-Ring-Capsules-220VAC-250rpm-/330920298564
01:08 Fiesta considering that this can carry 12 wires, i may be able to put the wires from the 3x stepper motors through it instead.
01:09 Fiesta and keep everything else on the rotating platform
01:10 Fiesta the steppers will handle noise much better
01:10 mbass-afk
01:13 Fiesta on another topic. Does anyone know what a sky-cam's coordinates system is called? is it polar?
01:13 Fiesta i've worked out most of the math and code already (just need cleaning), but i'm not sure what to call what i'm doing.
01:14 dumbass-afk umm, i forget who here has the telescope, but we do have a aussy in here with that data,, somewhere, if ic an find him
01:14 Fiesta i input an XYZ coordinates. And it spits out rotation coordinates to the servos, or stepper motors
01:14 Fiesta 3x rotations.
01:15 dumbass-afk keep asking every now an then, it may be 4pm htere, but it's 1am here, i'm asleep
01:15 Fiesta but really those rotations are just adjusting the lengths of the 3x suspension strings
01:15 Fiesta it's similar to a delta robot
01:15 Fiesta ok i'll just look into that, see what they call that math
01:16 Fiesta if your'e going to bed, thx for your help :)
01:17 dumbass-afk zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
01:24 Faek Try searching spherical coords
01:43 Fiesta i could put a mirror on the servo instead of the phone/camera itself. Have the camera looking up the hollow shaft.
01:44 Fiesta then all i need to rotate is the servo
01:44 Fiesta anyway, lots of solutions, yay
10:14 GuShH_ rue_house: got the thrust bearing, the new one came with the races and the number of course.
10:14 GuShH_ generic china crap, they didn't have SKF or anything better in stock...
10:15 GuShH_ should work, I guess.
10:15 GuShH_ same dimensional specs.
10:15 GuShH_ but steel "retainer"
10:15 GuShH_ now, should I put the crimped side down or up... I guess down...
10:16 GuShH_ this is the size http://www.amazon.com/51108-Thrust-Bearing-40x60x13-Bearings/dp/B002BBMLGM got at the skf store (funny, they didn't have their own brand in stock)
10:16 GuShH_ I don't think I can fit the races, since originally it didn't have any... so it wouldn't work properly if I did fit them
10:17 GuShH_ which is odd come to think of it, why isn't it there...
10:21 GuShH_ cool though, now I have a bearing supplier :>
10:21 GuShH_ will need some tiny thrust bearings for the lathe
10:21 GuShH_ it doesn't have any on the quill of the tailstock or some of the handles
10:22 GuShH_ it's not terribly bad but you can feel it
10:23 GuShH_ if they were ball bearings the 608 would work fine
10:23 GuShH_ but they are too thick and for that application thrust bearings are the answer
10:23 GuShH_ or a combination of both, radial...
11:52 simon what does 4WD stand for when speaking motors/wheels. I think the 'D' stands for differential?
11:54 SlaveToTheSauce drive
11:55 simon so it's 4-wheel drive. :)
11:56 SlaveToTheSauce ya
12:02 simon can anyone tell me if http://www.lynxmotion.com/p-860-a4wd1-combo-kit-for-autonomous-botboarduino.aspx refers to a product that only needs assembly and an additional battery to run senselessly around?
12:16 SlaveToTheSauce looks like it
12:17 SlaveToTheSauce that sure is a lot of money for what you get
12:18 GuShH_ simon: don't waste your money on that
12:18 GuShH_ SlaveToTheSauce: weasel stores
12:18 GuShH_ they're everywhere.
12:18 GuShH_ they resell china shit to idiots.
12:19 GuShH_ grab any 4wd toy you can find that suits your needs, mod it... way cheaper, or build from scratch, way cheaper.
12:19 GuShH_ otherwise you are just paying premium for an unfinished toy
12:20 GuShH_ rue_house: all assembled, new oil, new grease, all nicely packed... turns freely by hand, which it obviously didn't before... time to do a limited power test for a few secs, if all goes well full assembly and it's done!
12:21 GuShH_ don't want to run it dry for more than a few cycles otherwise the seals burn up, but it's all lubed with silicone right now which should be ok for a few cycles.
13:07 GuShH_ hrmm a bit leaky on the high side, need to take it apart the seals are compressed... but I couldn't source new ones so silicone it is...
22:29 GargantuaSauce_ http://www.youtube.com/watch?v=i_M4gtNkNHQ
22:33 robotustra_ ask this robot to build a house
22:35 robotustra_ not bad but too small
22:35 robotustra_ for big fun
22:36 robotustra_ this guy has an organ at home
22:39 robotustra_ walking like human is very nice http://www.youtube.com/watch?v=-Vg-BdXps50&list=UU-ujS0hAM5-RNMRyI4HUZmA
22:44 rue_shop3 but is it static
22:47 GargantuaSauce_ are you kidding
22:47 rue_shop3 is it a static motion sequence
22:48 rue_shop3 cant tell
22:48 rue_shop3 its not disturbed :)
22:48 rue_shop3 (the last vid)
22:48 GargantuaSauce_ theres no way that would work if it weren't dynamically controlled
22:48 GargantuaSauce_ centre of balance is way too high
22:49 GargantuaSauce_ if you watch the next one in the playlist he has it on stilts
23:25 dumbass-afk add one scoop of vanilla to the blender , just the vanilla , do not add the scoop
23:29 armyofevilrobots Wow, that is super impressive.
23:29 armyofevilrobots the dynamic walker I mean.
23:30 mbass-afk builds a set of molds, chill in freezer, pour vanilla into the mold, set back in freezer for 10 minutes, open, remove frozen vanilla, add an actual scoop of vanilla to the ble
23:31 dumbass-afk ice bucket : http://designerthinking.com/images/misc/bucket%20of%20water%20of%20water.jpg
23:40 GargantuaSauce_ http://www.invensense.com/mems/gyro/mpu9150.html i should get me a tape of these