#robotics Logs

Oct 04 2017

12:15 AM sparrowsword: Hello! Was wondering if anyone could point me towards a DIY robotic arm that uses suction cups?
12:20 AM rue_house: are you moving business cards?
12:20 AM sparrowsword: very strong sticky notes
12:20 AM rue_house: k
12:20 AM sparrowsword: 3 pieces of paper is probably a lie
12:20 AM rue_house: sonds like a good ballpark
12:20 AM sparrowsword: im assuming 10lbs of suction
12:20 AM sparrowsword: or however that is measured...
12:21 AM sparrowsword: sorry
12:21 AM sparrowsword: no.. 3 sheets of paper
12:21 AM rue_house: http://ruemohr.org/~ircjunk/robots/arm10/slide.htm
12:21 AM rue_house: how does that look like it compares to your skillz?
12:21 AM rue_house: for building
12:21 AM rue_house: maybe something more 3d printed?
12:22 AM sparrowsword: my printer itself was a diy
12:22 AM rue_house: ok
12:22 AM sparrowsword: that was an interesting build.
12:22 AM sparrowsword: so yes, i believe i could create that arm
12:23 AM rue_house: as far as the suction, there are a number of amsll suction pumps you can get, use a can as an "accumulator" and there are a number of valves you can use
12:25 AM rue_house: https://www.aliexpress.com/item/2PCS-Micro-Vacuum-Pump-Medical-Mini-Negative-Pressure-Pump-DC-Pressure-Small-Air-Pump-DC3V-6/32791745569.html
12:25 AM rue_house: maybe?
12:25 AM sparrowsword: im pretty sure these are strong enough... https://www.amazon.com/3V-6V-Motor-Vacuum-Aquarium-Oxygen/dp/B074PPV6QH/ref=sr_1_2?ie=UTF8&qid=1507091794&sr=8-2&keywords=5V+vacuum+pump Honestly, ive seen the uarm, and it suites my needs, except i need something that can provide a 100 degree angle from looking straight down as a starting point
12:25 AM rue_house: :) yup
12:26 AM sparrowsword: there is no documentation that i have found giving that information for the uarm..
12:26 AM rue_house: uarm?
12:26 AM sparrowsword: http://www.robotshop.com/en/uarm-swift-standard-4-degrees-of-freedom-metal-robotic-arm.html#Specifications
12:27 AM rue_house: https://www.aliexpress.com/item/3-4-DC-12V-PP-N-C-Electric-Solenoid-Valve-Water-Control-Diverter-Device/32799658533.html
12:27 AM rue_house: that should be a good valve for the low/negitive pressure
12:27 AM rue_house: wow, $500 you have lots of money to burn!
12:28 AM sparrowsword: its a weeks wages
12:28 AM sparrowsword: hence my concern with the arm fitting my needs
12:29 AM sparrowsword: however that investment is far worth the return
12:29 AM rue_house: I put less than $40cad into that one I was showing you, but it took time to make
12:29 AM sparrowsword: ive got more time than money
12:29 AM sparrowsword: which is why i will try an attempt to build my own, and borrow ideas from uarm
12:30 AM rue_house: I can give you any design information from mine
12:30 AM rue_house: you need some flat plastic to start the base, I flatten underground electrical conduit
12:31 AM rue_house: http://ruemohr.org/~ircjunk/tutorials/mech/p1010110.jpg
12:31 AM sparrowsword: you need some flat plastic to start the base, I flatten underground electrical conduit
12:31 AM sparrowsword: this does not make sense to me
12:32 AM rue_house: that, on the left, is underground electrical conduit(pipe)
12:32 AM rue_house: pvc, its called "teleduct" or otherwise "db2"
12:32 AM sparrowsword: ohhh ok
12:32 AM sparrowsword: pvc yeah im familar
12:32 AM rue_house: 2" minimum, upwards of 4"
12:33 AM rue_house: but if you have somewhere you can just buy pvc sheet, go for it
12:33 AM rue_house: I dont
12:33 AM Triffid_Hunter: rue_house: ltns :)
12:33 AM rue_house: I'm up too late
12:34 AM rue_house: ... and your up early
12:34 AM sparrowsword: do you have an autocad file?
12:34 AM rue_house: .... not for the base, "bigger is better"
12:34 AM sparrowsword: so another constraint of my project is i need it to be mobile
12:34 AM rue_house: there are no critical dimentions, less the hold in the middle
12:34 AM rue_house: ok
12:35 AM sparrowsword: it can be very tall, but probably not more than 3x3"
12:35 AM rue_house: its all mounted on the pipe fitting... that I should have you 3d print cause I used a lathe to size a pipe down...
12:35 AM rue_house: can you print abs?
12:35 AM sparrowsword: just pla
12:36 AM rue_house: ok
12:36 AM rue_house: that can work
12:36 AM rue_house: thats all mine are
12:36 AM sparrowsword: if i absolutely haveto i can print abs
12:36 AM rue_house: ok I have autocad for the side plates
12:36 AM sparrowsword: okay sweet!
12:36 AM rue_house: sparrowsword, I'm in gmt-8 what timezone you in?
12:37 AM sparrowsword: same
12:37 AM sparrowsword: my 9-5 is graveyard
12:37 AM rue_house: ok, I have to go to bed, but I'm back from work at 5pm,
12:37 AM rue_house: ah
12:37 AM sparrowsword: i should awake by then
12:37 AM rue_house: we should rake togethor a package
12:38 AM sparrowsword: indeed
12:38 AM rue_house: I can get you the 3d models of whats printed, and we can work out what materials you need
12:38 AM sparrowsword: I cant wait :D
12:38 AM rue_house: you need 5 standard size servos, and an arduino pro mini for sure
12:39 AM rue_house: and an AC adapter, 5V capable of, say 3A or more
12:39 AM rue_house: ... and a usb->ttl adapter...
12:40 AM Triffid_Hunter: probably want pretty strong servos
12:40 AM sparrowsword: define?
12:40 AM sparrowsword: i have a nitro rc car with some replacement parts
12:40 AM rue_house: meh, the whole robot is balanced, so the servos only carry the load
12:40 AM Triffid_Hunter: MG996R are nice, but need spring or counterbalance since they'll still melt if you hold them stalled for too long
12:40 AM sparrowsword: i do beleive i have one, might even be stronger
12:41 AM rue_house: Triffid_Hunter, all the ones I'v made use the chineese S3003 servos, and their all ok
12:41 AM rue_house: https://www.youtube.com/watch?v=slxOrCXxXOg
12:42 AM sparrowsword: how about an airtronics 94359
12:42 AM sparrowsword: oh
12:42 AM rue_house: as long as its a standard size servo its good, if its not true digital, my controller software can operate it
12:43 AM rue_house: https://www.youtube.com/watch?v=5vLEtVLV71I
12:43 AM rue_house: https://www.youtube.com/watch?v=j4uz_yha9uI
12:44 AM rue_house: https://www.youtube.com/watch?v=3N7DNfg4p9I (I later fixed the problem that caused them to de-syncronize)
12:44 AM sparrowsword: do i need a 360 degree rotation?
12:45 AM rue_house: nope
12:45 AM rue_house: 300 will do just fine
12:45 AM rue_house: you can prettymuch even get away with 180
12:46 AM sparrowsword: oh that servo you mentioned is 10$ okay lols
12:46 AM rue_house: its $6 if you shop in the right places
12:46 AM sparrowsword: https://hobbyking.com/en_us/towerpro-mg996r-10kg-servo-10kg-0-20sec-55g.html?___store=en_us
12:46 AM rue_house: https://www.aliexpress.com/item/Smart-Electronics-1pcs-38g-S3003-Standard-Servo-For-RC-Futaba-HPI-Tamiya-Kyosho-Duratrax-GS-racing/32526298732.html
12:47 AM rue_house: https://www.aliexpress.com/item/5pcs-High-quality-plastic-New-38g-FOR-Futaba-S3003-Servo-for-rc-toys-RC-Helicopter-car/32546595421.html
12:47 AM rue_house: https://www.aliexpress.com/item/FREE-SHIPPING-hot-selling-servo-standard-s3003-for-Remote-Control-Toy-car-Truck-Helicopter-Boat-toys/32340799687.html
12:47 AM rue_house: etc etc
12:48 AM sparrowsword: do you recommend a plastic or metal gear?
12:48 AM sparrowsword: ive personally had better luck with metal... but i havent done robotics.. just rc
12:48 AM rue_house: I'v put over 90 hours on one of the robots that has plastic gears with no signs of failure
12:49 AM sparrowsword: so.. doesnt matter?
12:49 AM rue_house: I'd say it dosnt'
12:49 AM sparrowsword: okay
12:49 AM rue_house: that marbel cant weigh much more than what you want to do, and you dont have a big gripper on it
12:49 AM sparrowsword: oh that mg996r looks like it has 60 degrees of rotation?
12:50 AM rue_house: servos are advertized as "90" but will usually do 180+
12:50 AM Triffid_Hunter: mine had 180
12:50 AM Triffid_Hunter: just need to widen the pulse width.. 750us-2250us instead of the normal 1-2ms
12:52 AM sparrowsword: rue_house: what do you suggest for making this arm mobile?
12:53 AM sparrowsword: If you are still awake :p
12:55 AM rue_house: it uses a pipe coupler to attach to the base,
12:55 AM rue_house: just put it in something else
12:56 AM rue_house: https://images-na.ssl-images-amazon.com/images/I/613Nx8dCeAL._SY355_.jpg
12:56 AM rue_house: but, upside down
12:56 AM rue_house: held onto the sheet with an electrical pipe but
12:56 AM rue_house: nut
12:57 AM sparrowsword: hmm, okay. I
12:57 AM sparrowsword: hmm, okay*
12:57 AM rue_house: https://mobileimages.lowes.com/product/converted/031857/031857491024.jpg
12:58 AM rue_house: http://ruemohr.org/~ircjunk/robots/arm10/slide.htm
12:58 AM rue_house: is there a pic in there?
12:58 AM rue_house: if not
12:58 AM rue_house: http://ruemohr.org/~ircjunk/robots/arm9/slide.htm
12:58 AM rue_house: http://ruemohr.org/~ircjunk/robots/arm8/slide.htm
12:58 AM rue_house: http://ruemohr.org/~ircjunk/robots/arm7/slide.htm
12:59 AM sparrowsword: one more contraint that idk if i have mentioned...
12:59 AM rue_house: the arm9 shows it
12:59 AM sparrowsword: i need it to reach 1/2" to 7ft
12:59 AM rue_house: 7 feet?!?
12:59 AM sparrowsword: approximately 6 inches away from its target
12:59 AM sparrowsword: indeed
01:00 AM rue_house: hah
01:00 AM rue_house: this arm is much smaller
01:00 AM sparrowsword: thought about making this arial..
01:00 AM rue_house: 7 feet...
01:00 AM rue_house: that other robots not gonna do that
01:00 AM sparrowsword: pretty sure it will reduce the duration length significantly..
01:00 AM rue_house: but you said portable
01:01 AM rue_house: did you want to put this small arm on a slider?
01:01 AM sparrowsword: yes
01:01 AM rue_house: can you move the job instead of the arm?
01:01 AM sparrowsword: im attempting to replace labels in a warehouse
01:02 AM rue_house: ok
01:02 AM rue_house: why use an arm?
01:02 AM sparrowsword: what other method?
01:02 AM rue_house: how about a large xyz ... ____- bot
01:02 AM rue_house: rectangular
01:02 AM sparrowsword: example?
01:03 AM rue_house: hmm
01:03 AM rue_house: like the robots that move boxes on and off of shelvs in automated warehouses
01:03 AM sparrowsword: yes
01:03 AM sparrowsword: that is step 2
01:03 AM sparrowsword: or project 2
01:04 AM sparrowsword: couldnt i just put the arm on some type of lift?
01:04 AM sparrowsword: driving lift*
01:05 AM rue_house: http://thnet.co.uk/thnet/robots/Env1.gif
01:05 AM rue_house: they aren't suitable for the 'generic everything' so they aren't seen toooo often
01:06 AM rue_house: but it would work well in what it sounds like you want to do, quite easy to build too
01:07 AM rue_house: http://1ugn2l2m3z2y31d4y73c1m5w.wpengine.netdna-cdn.com/wp-content/uploads/2014/11/Festo-3d-Gantry.jpg
01:07 AM rue_house: and put it on a wall instead of a floor
01:07 AM rue_house: 7 feet...
01:08 AM sparrowsword: and probably 150ft long
01:08 AM rue_house: good rails are an issue
01:08 AM rue_house: tho, ...
01:08 AM rue_house: yes... yes....
01:09 AM sparrowsword: so this system can be used with suction cups?
01:09 AM rue_house: suxtion cups to hold the paper, right?
01:09 AM sparrowsword: yes
01:09 AM rue_house: totally
01:09 AM sparrowsword: cant the railing be a slider on ball bearings?
01:10 AM sparrowsword: or something of the sort
01:10 AM rue_house: http://www.homedepot.com/p/Stanley-National-Hardware-6-ft-Chrome-Closet-Rod-in-Polished-Chrome-BB8182-6FT-ROD-CHR/203951146
01:10 AM rue_house: might work for rod, with some printed wheels and printed couplers
01:11 AM rue_house: plstic pipe isn't ridgid enough
01:11 AM rue_house: and most stnadrd metal pipe is too rough
01:11 AM rue_house: copper pipe is too expensive
01:12 AM rue_house: tho maybe less than that clothes hanger rod
01:12 AM sparrowsword: im still kinda fixed on the idea of the arm...
01:12 AM rue_house: you can, but by the time you have the gear to move the arm around, your dumplicating your work
01:12 AM sparrowsword: the placement of labels isnt exactly rectangluar
01:12 AM rue_house: dunno
01:13 AM sparrowsword: hmm
01:13 AM rue_house: your tolerance is +-0.25"?
01:13 AM sparrowsword: yes
01:14 AM rue_house: quite reasonable
01:14 AM sparrowsword: ive thought about using lidar to identify the placement of the labels, do to the odd shapes
01:14 AM sparrowsword: not of the paper, but the location
01:16 AM sparrowsword: the locations are all horizontally level
01:17 AM sparrowsword: Anyways, i must now be attending my 9-5... Thank you so much for your help!!!
01:18 AM rue_house: meh, so much for building another arm
01:19 AM sparrowsword: still think im leaning towards it
01:19 AM sparrowsword: just gotta figure out how to make it mobile... up to 7ft
02:09 AM Triffid_Hunter: over 2m? the torque at your joints will be incredible if you don't have it carefully counterbalanced, and the mechanical power required to move it at reasonable speed will become a consideration
02:47 AM Jak_o_Shadows: plus, any jitter will make it move a lot at that sort of distace
03:48 AM deshipu: oh, the infinite budget post-it-notes guy again?
06:22 AM justasking: do you guys recommend an arduino or an raspberry pi for robotics projects? I want something like a driving car with a camera and some sensors attached in the end
06:29 AM Tom_L: pc
06:32 AM justasking: Tom_L, was that targeted at me?
06:32 AM Tom_L: yeah why not?
06:33 AM Tom_L: they're cheap
06:33 AM Tom_L: os is free
06:34 AM Triffid_Hunter: justasking: both
06:34 AM Triffid_Hunter: justasking: RPi is great at cameras and WiFi, arduino is great at controlling motors
06:35 AM justasking: Tom_L, what is pc? I mean what do you mean with pc?
06:36 AM justasking: Triffid_Hunter, but I am a total noob at assembling stuff on my own. I really wanted to build a small car first and tried to find any tutorials on how to do that but it was pretty hard
06:36 AM justasking: I want to go with some preassembled car building kit now
06:37 AM justasking: and they normally are made for either arduino or raspberry pi
06:37 AM Triffid_Hunter: justasking: plenty of arduino robots around
06:37 AM Triffid_Hunter: haven't seen the RPi ones
06:37 AM justasking: https://www.waveshare.com/wiki/AlphaBot
06:37 AM justasking: they support both
06:38 AM justasking: and the second version of that even supports only raspberry pi
06:38 AM Triffid_Hunter: justasking: go with that then
06:39 AM justasking: I have a feeling that the arduino processor is a bit to weak for my purposes, but on the other hand I read on reddit that a raspberry pi with a full blown OS isn't actually what you want to control motors because of the os interrupts
06:41 AM Triffid_Hunter: justasking: that's why I said both :P
06:41 AM justasking: :D
06:42 AM Triffid_Hunter: justasking: RPi can do lots of high level processing that's simply impossible for the arduino, but it sucks at getting signal timing stuff right due to all the shenanigans that application processors running modern OSes get up to
06:42 AM Triffid_Hunter: arduino is *designed* to get signal timing stuff right
06:42 AM justasking: do you have a good kit or tutorial in mind for building something like that supporting both? or would you recommend getting the alphabot
06:42 AM Triffid_Hunter: so it's not an either/or question, in fact they complement each others' abilities perfectly
06:43 AM Triffid_Hunter: justasking: I've been doing EE for too many years to be able to recommend an all-in-one kit.. if all you're doing is slowly driving around your house, the timing isn't super critical and the RPi one will let you do your other stuff
06:43 AM Triffid_Hunter: however if you're making a balancing robot, use an arduino because the RPi's variable timing will make it fall over
06:44 AM Triffid_Hunter: and then of course you can simply plug the arduino into the RPi and have them talk to each other, then you can have the best of both worlds and do whatever you like
06:44 AM Jak_o_Shadows: agree with Triffid_Hunter
06:45 AM Jak_o_Shadows: also, I think I may have slightly fried the 5V somewhere along the lines for my alarm clock on the stm32
06:45 AM Jak_o_Shadows: So that's jolly good motivation to power it properly
06:46 AM justasking: I'd really like to make a robot that takes pictures and tries to "catch" (just drive beneath) a small ball or something I throw
06:47 AM Triffid_Hunter: justasking: catching thrown objects is probably gonna need something rather stronger than a RPi for the computer vision
06:47 AM Triffid_Hunter: that's actually a really hard thing to achieve
06:47 AM justasking: yes I thought so
06:47 AM justasking: but I'd like to have a hard challenge and maybe fail and then try something easier
06:48 AM justasking: but I thought that maybe in some special cases (non moving background) I could try to get something to work that calculates the approximate direction from 2-3 pictures
06:48 AM justasking: I'd also like to try machine learning approaches later on
06:48 AM Jak_o_Shadows: Grabbing a still ball is probably much easier
06:49 AM Jak_o_Shadows: no real time limit
06:49 AM justasking: How would I "grab" it with a car?
06:49 AM justasking: just driving to it you mean?
06:49 AM Jak_o_Shadows: dunno
06:50 AM Jak_o_Shadows: some kind of jaws?
06:50 AM justasking: Triffid_Hunter, but what would you recommend instead of a all-in-one kit for someone who unfortunately hasn't studied engineering or something related
06:51 AM justasking: but maybe I am just going with the alphabot, it supports both which is actually exactly what I want as it sounds
07:01 AM justasking: ok I am going with the alphabot now, I don't find any good comparable stuff
07:01 AM justasking: thanks a lot for all the help Triffid_Hunter
07:01 AM justasking: Jak_o_Shadows, thank you too
07:01 AM Jak_o_Shadows: no worries dude
09:45 AM rue_house: https://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic
09:45 AM rue_house: didn't think of twist
09:46 AM rue_house: that expalins a few things tho
09:48 AM SpeedEvil: What do you mean? It explains nothing, other than that GR is a good explanation of spacetime.
09:50 AM rue_house: just need to know what, other than mass, can create a space-time dimple
09:51 AM rue_house: I blame diagrams like that for me not being able to mentally picture spacetime in 3 dimensions
09:57 AM SpeedEvil: Spacetime is not 3 dimensional, it's right tehre in the name.
10:01 AM deshipu: we actually don't know how many dimensions it has
10:02 AM deshipu: somewhere between 8 and 20
10:29 AM veverak: nice
10:29 AM veverak: :)
04:18 PM tttb3 is now known as tttb
08:10 PM rue_shop3: pff
08:10 PM rue_shop3: I'm not getting that small
08:10 PM rue_shop3: yet