#robotics Logs

Jul 28 2013

00:00 Gargantuasauce used a lot on satellites
00:00 GuShH ..
00:02 MrCurious really
00:02 MrCurious wonder if its possible to spin one fast enough to exert enough force to support its weight
00:03 Gargantuasauce have you never balanced a toy gyroscope?
00:03 MrCurious was thinking more along lines of flying saucers...
00:03 Gargantuasauce lol
00:04 robotustra MrCurious: do you know how they fly
00:04 robotustra ?
00:04 Gargantuasauce here we go
00:05 MrCurious i thought i did, but whenever i try to remember, i see a painful piercing white light, and my butt gets itchy...
00:05 robotustra :)
00:08 MrCurious so far, this leap motion has not impressed me
00:08 robotustra I told you I told!
00:10 MrCurious yup
00:10 MrCurious still need to play with it api and see if it gives any interesting sensing
00:14 RifRaf wow, i added variables and calulate angle depending on rod radius and pitch, and it works
00:14 RifRaf parametric :)
00:15 RifRaf need to keep going
00:15 MrCurious so glad my kitty is eating again
00:18 RifRaf there must be a way to automatically calucate the offset based on angle
03:02 Gargantuasauce wowow i am compiling openscad and one of the opencsg modules made gcc allocate several gigabytes of memory
03:10 RifRaf this last ball screw i made is the best yet, is soo smooth
03:11 RifRaf helps to have correct angles i guess
03:11 Gargantuasauce how much force do you get out of it before it starts slipping?
03:11 RifRaf only issue was the m3 captive nut holders are a bit small, so reprinting
03:11 RifRaf many kg when tight
03:12 RifRaf will do a test with some scales soon
03:12 Gargantuasauce i demand videos
03:12 RifRaf yes they will come
03:12 Gargantuasauce this sounds too damn cool
03:12 RifRaf it is the coolest thing i have made yet
03:13 Gargantuasauce so do you think it'll actually be suitable for something like printer/cnc motion control
03:13 RifRaf yep
03:14 RifRaf will be designing motor mount soon to test in a x and y axis
03:15 Gargantuasauce guess i should get me some more rods
03:15 Gargantuasauce i will take this opportunity to bitch for the umpteenth time about mcmaster not shipping to canada
03:15 RifRaf you can just change the rod diameter in code now and the angle and it does most of the rest
03:16 RifRaf well you just say what pitch and diameter
03:17 RifRaf i get mine from china with free shipping
03:18 Gargantuasauce i will hit you up for a link to the supplier when i get back
03:18 RifRaf no worries
04:51 Jak_o_Android How much is the actual avr in arduinos, for small quantities
04:56 Skwint there are many, of different speeds and cpabilities, but
04:56 Skwint �1.50 upwards
04:56 Jak_o_Android Yeah, hence why I"m asking, as opposed to looking it up myself.
04:57 Jak_o_Android That dollars? symbol is stuffed here.
04:57 Skwint nah, that was british pounds
04:57 Skwint probably $2 ? it depends on the arduino - you will have to look it up
04:58 Skwint google thinks �1.50 = $2.30
04:58 Jak_o_Android ah, cool, I"m comparing to the msp430. The most feature one is about 2.5 USD
04:59 Jak_o_Android I sampled the one I have, gotta love TI.
05:04 Gargantuasauce depends on the source...digikey/mouser will be like $2-3
05:04 Gargantuasauce if youre willing to go china, i see a lot of 10 atmega328s for $1 apiece
05:05 Jak_o_Android haha. I would be, but if the difference us that small i'll probably stick with the msp430s
05:07 Gargantuasauce probably a good idea, that is a marginally less antiquated platform anyway
05:10 Jak_o_Android I'm pretty new, and still inexperienced even with the 430's, but yeah
05:11 Jak_o_Android Also so much less price gouging than arduinos, and less internet hate.
05:13 Gargantuasauce and you wont be subject to the anti-learning that the arduino api provides ;)
05:13 Gargantuasauce i think the stm32f0 is much more powerful at the same price point but i dont know specifics about the differences in peripherals and so on...but i'm sure that platform will serve you fine for now at least
05:16 Jak_o_Android My main influence was the absurdly cheap programmer
05:17 Jak_o_Android Also, I am using the arduino API, but ivve already had to dive in and fix stuff
05:17 Gargantuasauce well fwiw the st ones have the same deal, the dev boards are probably sold at a loss and have stlink onboard which can be used to program external micros as well
05:18 Gargantuasauce heh
07:44 poli Hello my good people of #robotics!
07:45 Jak_o_Android hello
07:46 ace4016 ahoy matey
11:43 MrCurious seems morning arrived early today
11:47 rue_house "ohmega, where is the ohmega key!?...ooooh...maybe I should just use an R...... dont want to, oh, wait, its a pencil..
11:48 zoplrdb wat...
11:48 MrCurious ohmega berry fish oil?
11:50 robotustra omega3
11:55 MrCurious i wish someone would set about to making this... http://www.mycncuk.com/forums/attachments/general-metal-wood-working/6817d1347319401-has-anyone-made-any-metal-tank-treads-1-16th-models-hammerstein-02.jpg
11:57 Tom_itx u r a someone
11:59 MrCurious thank you for that validation
12:14 zoplrdb uehue
13:24 GuShH MrCurious: you have a kitty?
13:32 MrCurious i have 9
13:32 MrCurious how many can i put you down for
13:32 MrCurious we have strays outside that bring us their babies
13:33 MrCurious i got 2013 models in, i have a few 2012 models left. how many can i put you down for
13:36 MrCurious GuShH do people in argentina eat cats?
13:43 robotustra MrCurious: in china
13:43 MrCurious thats right. korea eats dogs
13:44 robotustra they eat everything that moves and fly except trains and planes
13:44 MrCurious did you hear the indians were tracking some chinese spy
13:44 MrCurious planets
13:45 robotustra yep
15:16 poli I need to make a navigation system from encoders and a IMU
15:17 poli Is there some reference implementation for this somewhere? paparazzi maybe?
15:17 rue_house hmm
15:17 rue_house enocders on wheeles?
15:19 poli rue_house: I don't really trust that encorders will be the silver bullet. The thing is I will be working with mecanum wheels.
15:19 poli I can only imagine that encoder readings won't be THAT reliable for that configuration
15:20 poli I was expecting to find some open source implementation of a kalman of some sort to use as reference.
15:29 RifRaf rue_house, did you see the threadless ball screws?
15:34 poli I was really trying to find something like the optical mouses have
15:34 poli a laser surface-sensing laser that would give me precise displacement
15:35 poli this must exist, the technology is decades old
15:35 MrCurious why not just use a mouse
15:36 MrCurious or a usb cam aimed down
15:36 poli Mouse would have to stand too close to the ground.
15:37 poli The USB camera might be a solution, but I fear development effort will be huge.
15:37 MrCurious are you making a 2 wheel balance bot?
15:37 poli MrCurious: 4 wheeler mecanum
15:37 MrCurious then use quadrature encoder motors
15:37 poli I bet the mecanum wheels will ruin encoder data
15:37 MrCurious they will be possitionally accurate given a nice PID circuit
15:38 MrCurious i used steppers for my omni-wheel buiid
15:38 MrCurious doubt it
15:38 poli Mecanum wheels are something 85% efficiency
15:38 poli given that the only way to lose efficiency I can see is to mess up movement
15:38 poli I really fear the results of encoder navigation with that configuration
15:38 MrCurious well encoder motors for a start
15:39 poli That is for sure
15:39 MrCurious then refine as you determine if it is accurate or not
15:39 poli But I don't think there will be a silver bullet solution, except for a displacement sensor as the mouse has
15:39 poli but I have never seen that technology in robots
15:39 poli I might try to hack a mouse and increase laser power
15:40 poli And position it further from the ground hoping to get a reading
15:40 poli but that is a long shot
15:41 MrCurious why mecanum wheels and not omni (just curious)
15:42 poli MrCurious: the machine in question is a wheelchair
15:43 poli omni will be weird in that 45 degrees configuration
15:43 poli and mecanum are widely used for 200kg+ applications like that
15:43 poli and they are pretty inexpensive coming from china these days
15:44 MrCurious ok
15:45 MrCurious here may be your answer
15:45 MrCurious perhaps the answer is to invert a track ball
15:45 MrCurious suspend it on rails in the center
15:46 MrCurious should work for flat floors
15:46 MrCurious probably fail on gravel
15:46 MrCurious then again in a wheel chair... its going to be go this way til i say stop
15:46 poli floor cannot be 100% in the hypotesys :(
15:46 MrCurious not go this way 5 inches
15:47 MrCurious thy shal not remote control ones grand father...
15:47 poli I need imperfect floor for the solution.
15:47 MrCurious hmmm RC grandfather races... could catch on
15:48 poli who knows?
15:48 poli it might
15:48 poli http://www.youtube.com/watch?v=UMq9MGdArbM
15:50 poli I will have to design one :(
15:51 poli here you go: http://www.micro-epsilon.com/download/products/cat--optoNCDT--en.pdf
16:00 poli and here we go! http://www.otmtech.com/otm.asp
16:01 MrCurious i think that is teh mouse design that requires a special mat for the mouse to operate on
16:05 poli that old sun mice?
16:05 poli they sucked :(
16:06 poli check it out what they had in 1984 http://www.ri.cmu.edu/pub_files/pub3/hall_david_j_1984_1/hall_david_j_1984_1.pdf
16:23 MrCurious i loved teh sun mouse
16:44 poli Did you use them enough to have the special mirror pad wear out?
16:45 MrCurious nope
16:45 poli well
16:45 MrCurious i could see that being a issue
16:45 poli can you guess why I liked them at the beginning and them hated them some years later?
16:45 poli *then
16:46 Skwint tat the one that had a mirror with a grid drawn on it?
16:46 poli exactly that one
16:46 Skwint I used to have a VMS mouse that had two wheels underneath instead of a ball
16:46 poli that one I have never seen
16:47 Skwint the two wheels idea worked really well, actually
16:47 Skwint in all other respects it was a terrible mouse - it was circular
16:47 poli probably better than the ball, less dirt I would say
16:47 Skwint ergonomic if you were some sort of martian, presumably
16:47 Skwint yeah - it didn't jam up
16:47 robotustra guys, did you build Egypt pyramids?
16:47 Skwint nah - we were busy
16:48 poli robotustra: not really, just supervised
16:48 Skwint bunch of religious nuts piling rocks on top of each other :p
16:48 poli robotustra: I actually had a lot of them, but they were already quite old when I got my hands on them
16:48 poli the sun optical mice
16:48 robotustra and what input devices did they use?
16:49 poli PS/2
16:49 Skwint the pyramids?
16:49 robotustra workers that days
16:49 robotustra annunaks
16:49 Skwint man, the sphinx would have been so much easier to get going if they'd thought to invent USB _first_ :/
16:50 poli everything before usb sucked heavily
16:50 Skwint oh, I dunno, atleast it worked
16:50 Skwint and we learnt from it :p
16:51 poli The "auxiliary" port on your PC.
16:51 Skwint although, a quick look around this room, and it appears we didn't learn not to make 300 variations of a "standard" adapter
16:51 poli robotustra: any idea of what that was?
16:51 Skwint joystick or something wasn't it?
16:51 poli It was the parallel printer port
16:52 Skwint parallel? I thought we were talking old stuff? :p
16:52 poli They gave it a fancy name when you had to connect it to something else
16:52 poli Parallel is damn old!
16:52 robotustra USB invension is not a silver bullet anyway
16:52 Skwint it's true. I stuck a USB port in my werewolf and it's still not dead.
16:52 poli was it a silver USB port?
16:53 Skwint oh gods, does that matter too?
16:53 poli When it comes to werewolves, I am afraid yes.
16:53 Skwint hmmmm
16:58 poli were you bitten or something?
18:05 RifRaf my first thingyverse thing http://www.thingiverse.com/thing:124800
18:06 GuShH why is it thingiverse and not thingyverse if the word is thingy
18:06 RifRaf my typo propably
18:12 poli RifRaf: congrats
18:19 GuShH RifRaf: no, the domain is thingiverse
18:19 GuShH unless they've got both
18:19 RifRaf yes thingi it is
18:33 MrCurious sharknado? really. we are doomed
18:38 Tom_itx you should make the holes smaller so you could thread the machine screw into the plastic
18:39 Ademan is there a correct term for the "axle" of a servo?
18:39 Ademan the (part that connects to the servo horn)
18:39 Tom_itx output shaft?
18:41 RifRaf you can make smaller if you like
18:42 RifRaf have added lots of variables to make it easy
18:43 Ademan RifRaf: ?
18:43 Ademan Tom_itx: sounds reasonable
18:43 Tom_itx Ademan, talking about this: <RifRaf> my first thingyverse thing http://www.thingiverse.com/thing:124800
18:43 RifRaf yeah?
18:44 Tom_itx since you joined the party late
18:44 Ademan Tom_itx: thanks
18:44 Ademan RifRaf: Tom_itx knew what I was asking :-)
18:44 RifRaf heh
18:44 Ademan That's awesome, I saw that on thingiverse, didn't look at the author though. Great job RifRaf
18:44 RifRaf i did not make the first one, just made a new version
18:45 RifRaf with 6 bears and mount in a single piece
18:45 RifRaf bearings :)
18:46 Ademan So how is this supposed to work anyways? Just friction?
18:46 Tom_itx yep
18:46 Ademan That actually would probably be awesome on Z rods for a 3d printer in case of a head crash
18:47 RifRaf yep
18:49 RifRaf the force needed to make is slip is adjustable, and requires way more force than normal printing forces
18:51 GuShH what's the big deal? this is nothing new
18:53 RifRaf is new to me
18:54 RifRaf used that lathe yet or just gonna diss people that actually make things?
18:54 Tom_itx the idea has been around for a long time
18:54 RifRaf make something so i can mock
18:54 RifRaf yes, thats why its a good idea
18:54 GuShH this must be equivalent to the arduino community discovering constant current sources
18:55 GuShH RifRaf: so old ideas, such as genocide, are good because they've been around for a long time, too?
18:56 GuShH Also so far you've mocked me, I've yet to mock you.
18:56 Tom_itx somewhat
18:57 MrCurious really clever. print a "." in a super tight loop on avr, and its locked tight
18:58 RifRaf GuShH well if you had some you would see the neatness, all everyone else thinks is that they slip
19:00 GuShH I didn't say they were good or bad, and I didn't mention whether they slipped or not either. Take it on them not me?
19:01 m_itx gives GuShH some booze to chil
19:01 GuShH You two are on 11, I'm not.
19:01 Tom_itx me?
19:01 Tom_itx no
19:01 GuShH You!
19:02 ShH takes whatever RifRaf has been ta
19:03 RifRaf heh i am just working away here, just dug a 4mm trench into my bed because i forgot to sence tool after a change
19:03 GuShH RifRaf: yesterday was my birthday, so I didn't even touch the welder. I did however buy myself an autodarkening helmet, so that's sorted. Tried it today, works very well for the price. The manual mentions a lithium cell, but it must be on the other side of the module, couldn't see any lids.
19:04 RifRaf GuShH ok sorry, i know you are trying, and happy birthday for yesterday
19:04 Tom_itx those shields are cool
19:04 GuShH I'd save you some cake but it may not arrive in an edible state.
19:04 Tom_itx i got one as well
19:05 Tom_itx i think mine has solar cells on the face
19:05 GuShH I was between one with two switches for sensitivity and delay or this one with pots, decided for this one.
19:05 GuShH yeah they do
19:06 GuShH and what seems like two LDRs in there
19:06 GuShH I swear I can hear it "click" when it changes state, but maybe I'm nuts.
19:08 GuShH wish I had windows like that at home
19:10 MrCurious restored the avr :D
19:24 MrCurious very nice
19:27 MrCurious moveto r, theta is working for degrees and cm units
19:34 rue_house step controller?
19:42 MrCurious yup
19:43 MrCurious sure, it comes with no guarantee of reaching the requested destination
19:43 MrCurious but in truth, neither do my feet, or those of a blind person
19:54 MrCurious and rotate works
19:57 MrCurious its enough to claim weekend victory
20:16 MrCurious GuShH: do you know the pope? he is from argentina.
21:10 GuShH MrCurious: are you drunk again?
21:10 GuShH I don't know him, I'm not a church guy.
21:10 GuShH And he's from another part of the country anyway.
21:10 MrCurious oh
21:10 ShH slaps MrCur
21:10 GuShH no more booze.
21:10 MrCurious no sunday is almost never for drink
21:11 GuShH oh?
21:11 MrCurious monday is always work, and i hate being tired for work
21:11 MrCurious causes too much pain
21:11 GuShH With all the bending over and such, I would imagine.
21:11 GuShH Although I thought alcohol was used to numb the pain?
21:14 MrCurious got my base obeying commands like rotate deg and moveto R,deg
21:15 GuShH gut. gut.
21:21 MrCurious my kitty gonna be ok
21:28 RifRaf yay
21:48 rue_house Tom_itx, could you look for a log entry with the keywords telephone datasheet from me?
21:53 Tom_itx hang on
21:53 Tom_itx in here?
21:55 Tom_itx the only reference i see is ^^ that one
22:09 rue_house I think it was in #garf, bbl
22:09 Tom_itx didn't find it there either