#robotics Logs

Aug 31 2015

00:01 blockh34d i think you may need to adjust the gradients based on what quadrant the angle is in
00:01 blockh34d but the right look up table would abstract all that away
00:02 blockh34d theBear: ah well i tend to work on trade for weed and obscure hardware so maybe we'll work out a swap
00:02 blockh34d pizza sounds good
00:03 ockh34d puts some pizza rolls in the
00:22 rue_school no it dosn't, your angles were wrong
00:22 rue_school <rue_school> the angles are 105.255, 146.3099, 108.435
01:41 blockh34d i picked arbitruary angles that i could replicate here on graph paper
01:41 blockh34d also i indexed them all from 0 not relative to each other
01:42 blockh34d but it still adds up to 360 if you take the spans between them
08:35 rue_school the angles dont match the data
08:35 rue_school er vise versa
08:36 theBear whadda you, a bikini contest model now ?
08:38 theBear i dunno about concentrate, but i did a bunch of soldering that needed doing, until a not-THAT-tiny bastard resistor "riffed my chill", which is really a point of shame for me, gettin' my chill all riffed (?kids these dayspfft) by an inanimate object, and such a not-big yet not tiny enough to justify any special treatment one too
08:40 rue_school ?
08:41 rue_school I'm gonna stick with my solution
08:41 theBear oh, ok, i hope it's up to your usual standards
08:41 rue_school theBear, so your fixing stuff?
08:43 theBear which reminds me, you know what i don't know in this arena... what can i salvage outta ya know, my almost anything, that'll lemme do 3 or 4 bidirectional level shifts, hmmm, oooh, i CAN probly switch the data for the control, and use a flipfloppable buffer.. what is that one ? 74245 ?
08:43 rue_school yup
08:44 rue_school there are some (jfet) based methods too, toml knows them
08:44 rue_school did you know the high level voltage for an avr is like .5V?
08:45 theBear yeah, but you know me, last time i asked you i needed a single anything-fet and ended up walking up the block to find a broken monitor that had been disposed :)
08:46 rue_school :)
08:46 theBear ummm, i dunno, maybe, it's been a while, but yeah, i'm fixin and kinda well, usin fixin' as a kinda excuse/arm-twister to get back up to being able to program an avr without even thinking about it, maybe even via usb !
08:48 rue_school if you get an arduino that has an isp you can write some usb programmer software to it
08:49 rue_school there is a way to do it without an isp, not sure on the steps
08:50 rue_school wow,m this morning is moving slow
08:50 theBear yeah i know, the igor approach, or the "we wanna be like igor but we'll make a fancier webpage and act all snooty about it" v-usb way in theory
08:51 rue_school tom got a m32-u2 board that I made a programmer from, its one of my top two programmers
08:53 rue_school give me a shout if you want to do some avr programming togethor
08:57 theBear heh, you're always top of my list, first i gotta get past the bootstrap, which i only partially done, but may be done tonight, should be next couple days, due to what i kinda promised a buddy would be done real soon :)
08:59 rue_school ? do you still have the parallel port programmer?
09:01 rue_school I dont remmeber if you had one of riffs or mine
09:02 theBear riff, par and the err, damned new number, MAX232, heh, almost couldn't remember the first bit :) be using that a little later, making a sub-version of flashrom programmer that never existed outside usb land before, but my new buddies over that channel sound confident at most it'll be a tiny tweak
09:02 theBear i got one of your half bridges i think, but i never had a schem or knew what fets it sposed to take :)
09:02 rue_school oooh
09:02 rue_school fo rwhich chip?
09:03 theBear tho you gave me the gift of driving vfd's with dirt cheap logic pushed past specs :)
09:03 rue_school hah, that was designed around the numbers I got from a vcr
09:03 theBear it's a big one, nuts soldered into the ... oh, ummm, i dunno, first one i stumble on, probly old mega8 or a 90s2313 if it's got the cahones
09:03 rue_school oh 4 fets?
09:04 rue_school it'll be an openservo
09:04 rue_school hip4081 and a tiny13
09:04 rue_school irf 1404
09:04 rue_school ?
09:05 theBear no micro, well, i dunno, i'll look when i go next door... i'm a lot better sorted these days, you'd be disgusted, but impressed if you asked for something obscure :)
09:05 rue_school heh, still have the music gear?
09:06 rue_school eek, gtg, later!
09:06 theBear of course, probly not much more/less, tho it's behind a big pile of dead k7-ish boxes this err, year
09:06 theBear l8r tater
11:40 Technicus Hello, does anyone have recommendations for a low cost alternative omni directional platform like this: < http://www.superdroidrobots.com/shop/item.aspx/triangular-omni-wheel-vectoring-robot-platform-ig32-dm/1458/ >?
11:48 robopal there is nexusrobot.com
11:48 robopal dont know the price
11:52 robopal well I saw a price online, goes above 1k euros
11:52 deshipu those omniwheels are pretty expensive
11:52 Technicus I am trying to find out if there is anything under 500.00 usd.
11:52 deshipu and not very good on terrain that is not perfectly flat
11:53 deshipu Technicus: I would just look for the omni wheels and geared motors and make the rest yourself
11:54 robopal Technicus, smaller wheel diameter platforms are less expensive
11:54 anon6732 if you need omni you could simply use three stationary wheels in a triangle set. simplest way to get a truly omnidirectional platform
11:54 robopal you want them this big?
11:55 Technicus The platform will be the base of a waste basket.
11:56 anon6732 if it hasn't to be fast, then my idea is the cheapest one.
11:57 anon6732 just three motors. any other option will need about 8 actuators or more
11:58 anon6732 and obstacles can be passed by big wheels
11:59 Cerealkill3r Hey guys, I have a small question it's not really about arduino
11:59 robopal what is really about Cerealkill3r? :D
12:00 Cerealkill3r i have an 28C64A microchip and i basically have no ideea how to upload code into it,i know i need something like a pickit :)
12:01 Cerealkill3r i also have a socket for it
12:02 Cerealkill3r unlike an arduino,i don't have a usb port to connect to,so my guess is i have to use a pickit and attach it to the socket?
12:03 anon6732 oh, that platform is already three wheeled..then I'm sorry. should check that first.
12:04 robopal Cerealkill3r, eeprom??
12:04 Cerealkill3r yes
12:06 Cerealkill3r I don't know much about robotics,i know some arduino basics and that's it :)
12:07 robopal there are projects online i see, for this device
12:08 robopal maybe you want to try some before you buy a programmer
12:10 Cerealkill3r I see
12:10 robopal in fact, i dont know if pic kit 3 can work with this device
12:10 Cerealkill3r but still,i have no ideea how to upload code to it
12:10 robopal stay around maybe someone else here will tell you
12:10 Cerealkill3r Thanks robopal
12:13 robopal i was about to say search for "arduino 28c64 programmer" its there
12:13 robopal :-/
17:01 blib anyone good with ultrasonic sensors here?
17:02 Tom_itx ask the real question
17:02 rue_school are there 3d printable omnii wheels yet?
17:02 mrdata i played with ultrasonic sensors a long time ago
17:02 mrdata it would try to echo-locate
17:02 rue_school $550 for that, wow
17:03 rue_school NiMh battery!?
17:03 SpeedEvil Why do you actually want omni-wheels?
17:04 rue_school I'm looking at the link of the platorm that was posted
17:04 SpeedEvil yeah
17:04 SpeedEvil I thought you were the original perpetrator of the question, I should have scrolled up.
17:07 rue_school http://www.thingiverse.com/thing:585724
17:07 rue_school I feel sorry for that servo
17:10 Snert__ it can barely lift the arm, let alone any load.
17:10 rue_school I'd be surprised if lifting that arm dosn't strip its gears
17:11 Snert__ amen.
17:11 Snert__ and the servos they always suggest are crap anyways.
17:12 Snert__ some of the HiTec ones are good, but still, they're at the low end of torque and ability.
17:12 rue_school real servos still cost real money
17:13 Snert__ good enuff for demo toys but not much else.
17:13 Snert__ if you wanna lift a can of beer you need a gear motor.
17:13 rue_school the last cheap ones I got jitter like all hell, even with a 100% stable input signal
17:16 theBear i don't have a gear motor, but i always manage:)
17:17 Snert__ ahhh yes. A carbon life form assisted beer lift mechanism.
17:17 Snert__ and they said arm meant processors.
17:32 rue_school http://ruemohr.org/~ircjunk/robots/arm9/p1060859.jpg
17:32 rue_school with descent servos these have been working ok
17:33 rue_school gear slop ads up fast
17:33 rue_school they make a fun toy
17:33 rue_school http://ruemohr.org/~ircjunk/robots/arm9/p1060858.jpg
17:34 Snert__ I like that bot.
17:34 Snert__ it could actually do something.
17:34 rue_school notice the one to its left?
17:35 rue_school http://ruemohr.org/~ircjunk/robots/arm8/p1060648.jpg
17:35 rue_school and behind it
17:35 rue_school http://ruemohr.org/~ircjunk/robots/arm4/p1060574.jpg
17:36 Snert__ I'm gonna start with a pan mechanism and see what I can do.
17:36 rue_school :)
17:36 rue_school have access to a 3d printer?
17:36 Snert__ make it home to position and be repeatable and have limit switches and position feedback.
17:36 Snert__ nope.
17:37 rue_school 3d printers are addicive
17:37 Snert__ I been looking at those. But I wouldn't want anything I can afford. I don't printed jaggies.
17:37 rue_school yea
17:37 Snert__ I hate printed jaggies.
17:37 rue_school there a LOT you can do with a heatgun, pvc pipe and glue
17:38 orlock jaggies?
17:38 rue_school http://ruemohr.org/~ircjunk/tutorials/mech/p1010110.jpg
17:38 orlock would you consider the thread count of satin to be jaggy?
17:39 orlock because the effect my prints have is like somebody pressed satin bloth onto them
17:39 orlock cloth even,
17:39 rue_school I have to play with the temp of my printer, its leaving webb all over its prints
17:40 orlock What about your retraction?
17:40 rue_school dosn't help
17:41 rue_school I'm trying to work out the drool rate too
17:41 rue_school you can see it as over extrusion at the end of a striaght run
17:41 orlock i just installed a new hobbed bolt
17:43 orlock i also bought a hot end mounting plate
17:43 rue_school good show
17:43 orlock made out of metal of some sort
17:43 orlock but somehowthe hot end is loose when i install it
17:44 orlock i tried doing it at about 1am though
17:44 orlock http://www.ebay.com.au/itm/LearCNC-Stainless-Steel-Hobbed-Bolt-for-Reprap-Mendel-Prusa-Rostock-3D-Printer-/200943504464
17:45 orlock upgraded from one like http://www.ebay.com.au/itm/3D-Printer-Hobbed-Extruder-Bolt-Wade-/331604364491?hash=item4d35290ccb
17:48 orlock apparently the cheap black chinese bolts can be "out of round" slightly
17:49 orlock http://www.ebay.com.au/itm/LearCNC-Aluminium-Hotend-Groove-Mount-Plate-JHead-RepRap-RAMPS-3D-Printer-/191500888232
17:49 orlock thats the mounting plate
17:49 rue_school hahah $12
17:49 rue_school heh $6
17:50 rue_school $9, hmmm
17:50 orlock the bolts very well machined compared to the cheap one - the teeth are actually sharp
17:50 rue_school bead blasted
17:50 rue_school I have problems when the teeth get full
17:50 orlock they should never get full
17:50 orlock they should always be empty
17:58 rue_school there will always be a few bits
17:58 rue_school I'm going grocery shooping
18:00 rue_school after maybe I'll go to librayr, tommorow I'll go see the dinasaurs, and we shall see about wed
18:12 Snert__ is a hobbed bolt used to engage with a worm drive gear?
18:12 Snert__ I never seen one before today.
18:12 orlock no
18:13 orlock its used to drive plastic filament
18:13 Snert__ Ic...it grips it and slides it along.
18:15 orlock theres a large gear drive with a hex hole in the center that the bolt fits into
18:15 orlock and a small gear that fits a stepper
18:15 orlock google "wades extruder" to see
18:16 orlock a bearing is used to push the filament against the hobbed bolt
18:17 Snert__ kool.
18:17 Snert__ A 3d printer is pretty much like an automated hot glue gun.
18:17 orlock yeah
18:20 Snert__ maybe if I can get control of a pan unit and stepper motors I can look into a 3d printer.
18:21 Snert__ I gotta have top of the line, though. Motor encoding. Limit switches. Position feedback.
18:22 orlock Snert__: It will cost you
18:22 Snert__ if I can do all that with a pan mechanism then I'm sure I can do a 3d printer.
18:22 orlock Snert__: the megacorp i work for, some of the other subsiduaries do all that stuff
18:23 Snert__ I'm not seeing more than 300.00 ... maybe a little more for the pan mechanism.
18:23 Snert__ a good gear morot with encoding is only 100.00
18:23 Snert__ I got all the duino stuff already.
18:24 orlock Kollmorgen? Portescape? Thomson?
18:24 Snert__ I never heard those names before but I'll keep them in mind
18:25 Snert__ I've seen encoding gear motors on Pololou before. Are they cheap shit?
18:26 Hyratel Snert__, depends what you want to do with them
18:26 Hyratel you should learn on "cheap shit" before dropping the big dollar
18:27 orlock Those brands i listed are likely to be hideously expensive
18:27 Snert__ I know what you mean. But in the end, that's a waste. If I'm headed for the good stuff anyways I'd rather start with good shit.
18:27 Hyratel Snert__, ding dong wrong
18:28 Hyratel you can fuck up cheaply several times, or fuck up expensive once
18:28 Snert__ depends on the fuckup is all. I'm not one that fries motors and dumb shit like that.
18:29 Snert__ hook my juice up backwards...lol..I don't make those mistakes.
18:29 Hyratel you can also prove logic more cheaply at small scale
18:29 Hyratel you can get encoder-fitted motors for ...
18:30 Hyratel https://www.sparkfun.com/products/13166
18:31 Snert__ that's why I'll start off with the pan mechanism first - based on this......
18:31 Snert__ https://www.servocity.com/html/super_duty_belt_drive_pan_syst.html#.VeTeTnuJKPU
18:32 Hyratel that's some serious ching
18:32 Snert__ if that's a success then I'll move onto the upper arm part of it.
18:32 Hyratel what are you making?
18:32 Hyratel you said pan/tilt
18:33 Hyratel is it for a robotic arm?
18:33 orlock ching?
18:33 Hyratel $$
18:33 orlock nah
18:33 Hyratel [cash register noise]
18:33 Snert__ I only said pan....and yes....a robotic arm.
18:33 Hyratel then that's ill suited
18:33 Snert__ that can actually lift a can of beer.
18:33 Hyratel it's only one bearing and not meant for transverse loads
18:33 orlock Hyratel: http://dovermotion.com/rotary-stages/
18:34 Hyratel transverse torque, rather
18:34 orlock Hyratel: theres your ca-ching
18:34 orlock ka-ching
18:35 Snert__ yikes...yea...I'll stick with the cheaper pan I saw.
18:35 Snert__ damn, that's nice equipment.
18:35 orlock cheers
18:35 orlock though i am just a sysadminm
18:36 Hyratel Snert__, so, what's your arm going to consist of?
18:36 Snert__ unknown. But not servo motors.
18:36 orlock you mean "hobby servo"? :)
18:36 Snert__ gear motors ...90 degree gear motors...and the like.
18:37 Snert__ not any servo available in the RC world.
18:37 orlock yeah
18:37 Hyratel Snert__, 'servo motor" only means it has closed loop positional feedback
18:38 Snert__ they are just too puny to handle picking up a full beer or do anything trooly useful.
18:38 Hyratel if you want to clarify "low power, small size, cheap" say hobby servo
18:38 Hyratel you need a closed loop servo for this
18:38 Hyratel but you probably won't use a hobby servo
18:38 Snert__ no. And positional feedback will occur via an outside, independant monitoring thing.
18:39 Snert__ external feedback I think of it as.
18:39 Hyratel Snert__, nope
18:39 Snert__ like when tha pan mechanism reaches home...I'll know it from 2 sources that must agree.
18:39 Hyratel it's called closed loop
18:40 Hyratel Snert__, seriously
18:40 Hyratel I'm using the STANDARD TERMS
18:40 Hyratel you can search them
18:41 Hyratel "closed loop control"
18:42 Snert__ I'm not gonna get that out of the box though. "out of the box" meaning for less than exorborant price.
18:42 Hyratel no?
18:42 Hyratel I call BS
18:42 Hyratel at least if you want to homebrew it
18:42 Hyratel print out a black/white line sticker, get an optogate
18:42 Hyratel thats your encoder
18:43 Hyratel heck, attach two or more, and you can do Greycode exact position
18:44 Snert__ uh-huh. read by a duino. that compares what the motor encoder says versus what the other positioning sensing says. The 2 will have to agree.
18:44 Hyratel Snert__, shaft encoder
18:44 Snert__ yep.
18:45 Hyratel so
18:45 Hyratel is this for a sellable product?
18:45 Hyratel or something just for playing with
18:45 Snert__ oh no, just for fun.
18:45 Snert__ but high quality fun.
18:45 Hyratel you're trying to run before you can walk
18:46 Snert__ I go straight to the 10speed. Fuck the tricycle.
18:46 Hyratel uh huh
18:46 Hyratel build it with lego first
18:46 Hyratel use a potentiometer and a printed paper encoder
18:46 Hyratel it's still closed loop
18:46 Snert__ I do better than that on my 1st try.
18:46 Hyratel that's *WHAT THAT'S CALLED*
18:46 Hyratel CLOSED LOOP
18:46 Hyratel CLOSED LOOP CONTROL
18:47 Snert__ I know. I'm just not going to waste $ on a sparkfun toy when I'm headed for the good stuff anyways.
18:48 Hyratel you have a very strange definition of waste
18:49 Snert__ I'm getting up2speed on the electronics side of it all now.
18:49 Snert__ which is the easy part.
18:50 Snert__ gotta learn more C though.
18:50 Snert__ but circuits and troubleshooting and building , all that's no problem.
18:52 Snert__ it's mainly identifying what I want the arm to do.
18:52 Hyratel then define that
18:52 Hyratel mock it up with cardboard
18:52 Hyratel make sure your proportions work
18:52 Snert__ good idea.
18:53 Snert__ I know I need a rotary base no matter what the upper arm is going to do so that's why I'm starting with just that piece of it.
18:54 Hyratel you need to know if the bearings will take the transverse torque
18:54 Snert__ yes, I'll be watching that.
18:55 Snert__ I can pretty well visualize where the stress points are with different designs.
18:56 Snert__ leverage and stuff I just kinda get.
18:56 Snert__ I'm sure I won't get it totally right the first time but I'll be well down the path.
18:57 Snert__ I'm aining to pick up a beverage can (12oz) and move it and sit it down. Repeatablly.
18:57 Snert__ aiming
18:58 Snert__ and anything of less weight or action that I want to do will fall under that 12oz. limit.
19:05 rue_school ooo
19:05 rue_school setterm -backgound blue
19:06 Snert__ that Dover Motion stuff makes me drool.
19:07 orlock Snert__: Yeah, very high end stuff.. i guess thats why we bought them
19:07 orlock Snert__: if that makes you drool, you would wet yourself here.
19:08 rue_school someone trying to do closed loop servo control?
19:08 Snert__ where are you?
19:08 rue_school I'm right here
19:08 orlock Snert__
19:08 orlock doh
19:08 Snert__ rue - I will be in awhile....just researching stuff.
19:08 Hyratel rue_school, Snert__ is wanting to do double-input closed loop control
19:08 orlock Snert__: sysadmin forthe company that owns dover motion
19:09 rue_school for controling what?
19:09 Snert__ a pan mechanism.
19:09 Hyratel a robotic arm shoulder rotator
19:09 Snert__ and add something on top of it later. Maybe an arm.
19:10 rue_school https://www.youtube.com/watch?v=QjOy9RdUZKA
19:10 rue_school awe its hard to see
19:11 rue_school https://www.youtube.com/watch?v=z2xWgEdiTwc
19:11 rue_school same mega32 control
19:11 rue_school gee my videos suck
19:11 rue_school where can i get someone to produce all my videos for free?
19:12 rue_school I have a note that I figured out double acting servos, but I dont know where my work is for it
19:12 rue_school is it bad to eat 10lbs of M&Ms in one sitting?
19:14 Snert__ rue - yes, if they were not sorted by color with your robot.
19:15 Hyratel rue_school, do you mean a servo that will take two concurrent input signals and make sure they agree?
19:15 rue_school did you see the two videos?
19:17 Hyratel rue_school, looking at second
19:18 rue_school there is also...
19:18 Hyratel what's the maximum safe response speed on the air servo
19:18 rue_school https://www.youtube.com/watch?v=4tG2bTOGxK0
19:18 rue_school THAT I didn't think I could actually do
19:19 rue_school its not a linear solinoid, its a normal one
19:19 rue_school safe?
19:19 rue_school no.
19:19 Hyratel voice coil servo
19:19 rue_school https://www.youtube.com/watch?v=Gg7K5X-_r2o
19:19 rue_school its a standard solinoid
19:20 rue_school that last one, i'm realtime controlling from across the room
19:20 rue_school I couldn't see the table, so doing the pushup was really hard
19:20 rue_school on that last one i have one mega32 controlling 4 loops
19:21 rue_school it takes serial control, analog feedback, and outputs direction and pwm
19:21 Hyratel rue_school, and the return spring makes it a voice coil
19:21 rue_school Hyratel, its not built linear tho
19:21 Hyratel linearity is hard
19:21 rue_school also voicecoils use a magnetized armature
19:22 rue_school the worst linearity issues were with the valve on the air muscle
19:22 Snert__ ok guys ...think gray code for positioning...got my food for thought. I know what gray code is so I'll look at implementing it.
19:22 rue_school I had to use a table to change the magnitude of the corrections
19:22 Snert__ thx...seeya when I need another jolt of good idea.
19:22 rue_school I'm happy to share the code from any of those projects
19:23 rue_school youtube, look up ruenahcmohr
19:24 rue_school https://www.youtube.com/watch?v=3N7DNfg4p9I
19:24 rue_school I wonder why the middle one isn't running
19:25 Hyratel https://www.youtube.com/watch?v=tgp3j-odseo
19:25 rue_school https://www.youtube.com/watch?v=eRF78fZiWuE
19:25 rue_school thats always fun
19:25 Tom_itx rue_school, did dude the other day school you on your math problem?
19:26 rue_school his solution didn't work
19:26 Tom_itx oh
19:26 Tom_itx well i know it was over my head..
19:26 rue_school mine does, so far
19:26 rue_school have to give it a torture test
19:28 rue_school well its nice to know that just cause NASA cant get a pulsejet to work dosn't mean the rest of the world cant
20:48 mrdata nice
20:56 ace4016 (they have a pulsejet working)
20:56 Hyratel rue_school, what? context please
23:50 rue_school the youtube video
23:51 rue_school anyhow, I got a gripper deisgn from thingiverse and in the process of trying to correct some minor things, found some major problems
23:51 rue_school it looks like someone tried to mod the model and screwed it up