[HN Gopher] Low Cost Robot Arm
___________________________________________________________________
Low Cost Robot Arm
Author : pbrowne011
Score : 469 points
Date : 2024-04-02 03:50 UTC (1 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| jerzmacow wrote:
| Wow, I was building a Thor 3D printed arm, and this project looks
| way better! I think I'm going to Pivot.
|
| Side bar: these servos are a game changer.
| brcmthrowaway wrote:
| Are the servos better than SG90?
| regularfry wrote:
| Dramatically. They cost (give or take) ten times more and
| weigh twice as much, for which you get (give or take) four
| times the stall torque, serial positional control, and a 360
| degree range of motion.
|
| Still got plastic gears though.
| michaelt wrote:
| They're "smart" which means you can form a serial bus of
| them, query individual motors' encoder positions and motor
| temperatures and whatnot, adjust the PID parameters yourself,
| and so on. You can also daisy-chain them together, which
| might reduce your cable routing problems.
|
| Downside is when they break, you're out $50 or more - and
| you're going to break at least one. And the manufacturer
| wants you to operate them at 11.1v which isn't very
| convenient. And when it comes down to it, it's still got
| plastic gears, a plastic case, and enough backlash to be
| noticeable.
| brcmthrowaway wrote:
| Wish there was something inbetween that and SG90!
| potatoman22 wrote:
| I printed a robotic arm for school. Unfortunately, we weren't
| using a high quality enough printer, so the tolerances were off
| and things didn't slot together well. I'd recommend people to
| know the precision of their printer before setting off to build
| this.
| dailykoder wrote:
| Learning this is part of the journey imho. You don't even have
| to know that you have to pay attention to tolerances
| beforehand. You'll inevitably learn about it when building such
| thing.
|
| Just always be aware that these things will never be perfect
| and don't get anxious because there are so many perfect looking
| projects on the internet. They most likely went through the
| same mistakes and might even have more people in the
| background. Just enjoy the journey
| throwup238 wrote:
| Alternatively, make everything just a tad out of tolerance and
| drill/sand/machine it to a more precise size.
| steve_adams_86 wrote:
| I tend to do this. I know I could get better at printing
| (though my printer is pretty old), but sand paper and a
| rotary tool are really fast and can be pretty precise and
| accurate too.
| moffkalast wrote:
| It's not so much the printer's fault as the slicer's.
| Calibration is key.
| numpad0 wrote:
| I'd PSA recommend anyone just add 0.25mm fit clearance to every
| single mating surfaces within their designs. It's not ISO or
| anything compliant - somewhere between Atrocious and Enormous
| range and perhaps an mechanical equivalent of Python code with
| no __main__, but just works for me, and it should for lots of
| purposes.
| easygenes wrote:
| Anyone know how the accuracy of this compares to the similar-cost
| adamb314/ServoProject arm? [1] It utilizes a servo mod adding
| dual encoders to compensate for backlash and achieves accuracy of
| +/- 0.05mm (enough to thread a mechanical pencil lead in and out
| of the tip of a pencil). [2] He's been working on the project for
| 5 years, with significant improvements still in the last year.
| [3][4] [1]:
| https://github.com/adamb314/ServoProject [2]:
| https://www.youtube.com/watch?v=SioCwvR_PYY [3]:
| https://www.youtube.com/watch?v=_4mrb2T706s [4]:
| https://www.youtube.com/watch?v=Ctb4s6fqnqo
| serf wrote:
| it should be similar given similar construction; one of the
| reasons dynamixels tend to be pricey is the dual inboard
| encoder setup.
|
| if price is a factor then a servo+encoders setup will always be
| cheaper; there are some dirt cheap encoders out there for the
| creative hacker. dynamixels offer a crappy value compared to
| DIY solutions, they're just easy to use off-the-shelf and have
| nice features that aid construction.. but hardly anything game
| changing.
| throwup238 wrote:
| _> but hardly anything game changing._
|
| Speak for yourself! When I worked on liquid handlers a decade
| ago the fully integrated servos were at least ten times as
| expensive as they are now.
|
| Every time I step away for a few years and jump back in,
| there seems to be at least a half dozen game changing pieces
| of hardware on the market.
| NalNezumi wrote:
| I've built my own GELLO setup (the setup the author based it's
| arm on) and it's quite neat, but as I only use it for
| teleoperation of an real arm, I wonder how useful this low cost
| arm really is? Considering limited range, probably backlash, and
| the limited torque
|
| Also it doesn't seems to use springs like GELLO which was a nice
| add, although the 3D printed parts where the spring was mounted
| broke quickly.
| monkeydust wrote:
| Cool, how are you controlling it, VR (Quest) type setup or
| something else?
| alex_suzuki wrote:
| Anyone who finds this interesting might also like this one, it's
| not DIY - comes fully assembled:
| https://www.waveshare.com/roarm-m2-s.htm
|
| I have one and the build quality is really impressive for the
| price point.
| ipsum2 wrote:
| How is the software support?
| alex_suzuki wrote:
| I've only just started using it via the web UI, no idea.
| dr_kiszonka wrote:
| Nice. What do you use it for?
| alex_suzuki wrote:
| Reproducible test scenarios for barcode scanning with a
| smartphone.
| dr_kiszonka wrote:
| Very clever. This use case would never cross my mind.
| devsda wrote:
| Unless it has to do something with the print quality
| itself, can't this be achieved using a stationary phone
| with its camera towards a monitor displaying 3D transformed
| barcode images ?
| alex_suzuki wrote:
| Yes, possibly. But reading from the screen is quite
| different from reading actual barcode prints, for
| instance you have to deal with Moire patterns and such.
| And frankly it was just a good excuse to buy an arm. Sue
| me! ;-)
| devsda wrote:
| > for instance you have to deal with Moire patterns and
| such
|
| My understanding is e-ink displays will not be suceptible
| to that.
|
| I might just have given you an excuse to buy a large
| e-ink display/monitor :)
| Yenrabbit wrote:
| Haha fair play, this is exactly how things should be!
| 2rsf wrote:
| I wish I had it a decade ago when I tested phone touch
| screens
| moffkalast wrote:
| There's also the 5-dof version that I've seriously considered
| buying at one point, but it's really hard to tell if the ROS 2
| integration is any good:
| https://www.waveshare.com/product/robotics/roarm-m1.htm
|
| A real shame there isn't a 6-dof one, since that's what you'd
| really need to grasp anything properly in the radius around the
| arm.
| mdrzn wrote:
| This is one of those things I have NO NEED FOR but I definitely
| would want one on my desk.
| singularity2001 wrote:
| Any such thing on amazon etc?
| fragmede wrote:
| How's the software side of this? How is the Dynamixel SDK to use?
| isquaredr wrote:
| The geek in me is drooling, but are there any practical home uses
| others have found for robotic arms? Hacking is always more fun
| with a good project
| dr_kiszonka wrote:
| An impractical use would be to have a few of them replace
| monitor arms in a multi monitor setup. You could then rapidly
| switch between a few configurations.
|
| Also, have one to stir pasta in the kitchen.
| Havoc wrote:
| I doubt this is strong enough to carry a screen
| etrautmann wrote:
| Pasta is one of the few things you're not supposed to stir
| while cooking?
| dr_kiszonka wrote:
| I think you should stir it occasionally. It might depend on
| the pasta, though.
|
| https://www.thekitchn.com/kitchen-mysteries-why-stir-
| pas-112...
| vasco wrote:
| Multi monitor robot arm stands would do some cool things. An
| automated rotating sequence when you boot up would feel like
| a scifi movie.
| throwaway38375 wrote:
| On the topic of automatically stirring pasta, I saw this the
| other day!
|
| https://www.amazon.com/StirMATE-Automatic-Variable-Self-
| Adju...
| adolph wrote:
| That is interesting and Amazon has a great algo for
| matching it to laboratory equipment consisting of hot
| plates and magnetic stirrers.
| PeterisP wrote:
| At 1.4 Nm torque, the main motors would likely struggle
| manipulating a 0.5 kg item, they aren't strong enough to hold
| a monitor.
| actionfromafar wrote:
| Sacrifice speed and add a gearbox?
| greggsy wrote:
| I'd use it to pick through and sort the massive pile of Lego my
| children leave behind after an Easter long weekend. Seems
| trivial to do identification based on the high quality corpus
| of block databases. Wouldn't have to be super quick - you could
| just leave it running overnight.
|
| I'm sure someone's written an interesting paper on the ideal
| sorting algorithm too (i.e. large things > small things vs.
| 'just pick up and place the nearest thing'.) I would personally
| just get it to sort them into basic sets before placing the
| trays back in their goddamn drawers.
| IshKebab wrote:
| Picking up and sorting Lego with a robot arm is pretty much a
| state of the art research project (a few years ago at least),
| not a hobby project.
| Grimblewald wrote:
| Depends on your defenition of hobby and if the hobby as
| part of it being enjoyable needs to produce something
| tangible in the short term. Following sota research,
| tinkering, trying new things in a field unrelated to your
| day job can be a fullfilling hobby.
| Terr_ wrote:
| I imagine it is strongly affected by whether the pile is
| already decomposed into individual bricks or not.
|
| The analysis and disassembly of a combined set of bricks
| can frustrate even human eyes, brains, and fingertips.
| 4gotunameagain wrote:
| The devil is in the details. In theory everything is trivial
| with enough SW dev hubris ;)
|
| Even just the path planning towards the block to ensure good
| grip and pick up is not a simple task. Consider all the block
| shapes, possible orientations, collisions..
| otikik wrote:
| My impression is that the fastest/easiest way to do it would
| be putting all the pieces inside hopper with the selector at
| the bottom. Perhaps using compressed air to push the falling
| pieces into different containers as they fall. I believe
| there's already something like that in produce factories,
| separating vegetables by state/size.
| otikik wrote:
| Oh look someone has already done something like that:
|
| https://www.youtube.com/watch?v=04JkdHEX3Yk
| boffinAudio wrote:
| I don't know why this can't just be a cleverly laid out
| arrangement of layered sieves, each one parsing a
| different object .. I don't see how it needs to be
| mechanical in any sense other than "pour in the lego
| junk, out it comes neatly sorted", a la coin-sorting
| machines ..
| flutas wrote:
| I could see people wanting to add on color detection for
| the bricks, but even that could still be solved by camera
| + servos/steppers and a chute that goes to different
| bins. No need for an arm.
|
| Doesn't stop me from wanting one though.
| Groxx wrote:
| The problem with sieves with Legos is that everything
| goes in the square hole:
| https://www.youtube.com/watch?v=Nz8ssH7LiB0
| otikik wrote:
| It is probably possible to do it, but the sieves would be
| quite big, just to account for the very large number of
| pieces, as well as having to "orientate" them correctly
| using only gravity.
| leoedin wrote:
| I interviewed once with a company that made rice and grain
| sorters. They have a massive hopper at the top and pass the
| grain in a curtain through a machine vision camera, and
| then decide in real time where each grain goes based on the
| image.
|
| Apparently pretty much every grain of rice you've eaten has
| been through a machine like that.
| otikik wrote:
| That is very interesting! Thanks for sharing. I did not
| imagine that rice was a good candidate for this
| michaelt wrote:
| _> Seems trivial_
|
| Said like someone who's never tried it :)
|
| For a start you're going to need a camera. Maybe more than
| one. You want depth sensing? Even an cheap choice like a
| RealSense is going to add another $250 to your costs. And
| you'll need a sturdy mount for it, the robot's going to
| vibrate the table and you don't want to suffer motion blur.
|
| Got the camera in a fixed location, over the area you're
| picking from? Then the robot's going to block the camera's
| view when it reaches in. No real-time hand eye coordination
| for you. Putting the camera on the robot's wrist? Now you've
| got motion blur problems - and reliability problems, because
| normal USB cables aren't designed for continuous flexing.
| You've also got a gripper in view all the time - and now the
| camera moves, things are always out of focus.
|
| The reach of the arm isn't long enough to give you many bins
| to drop items off into, considering the number of lego parts
| there are. The longer you make the arm, the greater the
| torque at the shoulder joint. Making the motors bigger? Now
| the elbow motor is heavier. Gearing them down? Now you've got
| gear backlash.
|
| Your Dynamixels will break, for some reason. Maybe eventually
| you'll figure out why. In the meantime, $50 each please.
|
| Parts like the small satellite dish https://www.bricklink.com
| /v2/catalog/catalogitem.page?P=4740... will prove very hard
| to grasp. And there's like 50 different colours, you're going
| to need to know your way around lighting and camera settings
| if you want to reliably tell transparent light blue,
| transparent medium blue and transparent dark blue apart.
|
| And that's before you get into questions like how to tell a
| 2x4 stud brick apart from two 1x4 stud bricks next to each
| other - or how to grasp a brick when an adjacent brick is
| blocking you from getting in with the gripper.
|
| Every single one of these issues is solvable - but by the
| time you've solved them all? You could have hand-sorted that
| lego 20 times over :)
| sgu999 wrote:
| > Even an cheap choice like a RealSense is going to add
| another $250 to your costs
|
| fyi, Luxonis is selling some for $150, I'm still meant to
| try them but they look quite good
| r2_pilot wrote:
| I happen to use a few of their cameras, and they
| generally work as advertised (satisfied Kickstarter
| backer for OAK D and OAK D lite, probably going to buy
| the OAK D pro at some point). But, while I did indeed pay
| less than 250 for them individually, their current active
| depth offerings are $350(and while my oak d is fine for
| my lit, varied environment, I do often wish it was a
| little more accurate). I thought the Lite was also around
| $200 but it's actually $150 as you said. It's a pretty
| good little platform for the price. Be sure to check out
| the experimental repo too :
| https://github.com/luxonis/depthai-
| experiments/tree/master/
| greggsy wrote:
| It's trivial to fork one of the several open source
| projects focused on this problem.
| 4gotunameagain wrote:
| For example ?
|
| [1] lists [2] which uses a robotic arm, but it is closed
| source
|
| [1] https://github.com/360er0/awesome-lego-machine-
| learning [2]
| https://www.thirdarmrobotics.com/q_and_a.html
| MOARDONGZPLZ wrote:
| They really spent a lot of time diving into the
| complexities of your question and I found it really
| interesting. Your handwavey, one sentence response
| without even an example (if there even is one??) is kind
| of rude in this context.
| Max-q wrote:
| I think the easiest way to collect the Lego pieces from the
| floor is by using a vacuum cleaner.
|
| Then look at the sorting as a separate problem :)
| otikik wrote:
| We have a "Lego sheet" - just a regular bed sheet that goes
| on the floor before playing with Legos. When it's time to
| collect, you make a "bag" with the sheet, grabbing (most
| of) the pieces, and then we "pour" them into the final
| container. The sheet goes in top of the pieces on the same
| container so it's also the first thing that comes out the
| next time.
| jrussino wrote:
| I guess this was a common enough solution that now you
| can find products that are essentially what you're
| describing, e.g.: https://www.amazon.com/SAM-MABEL-
| Storage-Basket-Play/dp/B0BV...
|
| From the item description: "TIDY UP IN SECONDS: Say
| goodbye to messy playrooms with our storage organizer!
| The play mat provides a dedicated area for creative play,
| and when it's time to pack up, simply gather the handles
| and tip everything back into the compact storage cube. "
| Animats wrote:
| Not much. I have a UArm on my desk, which is a lot like this
| one but with cheaper servos. It was too inaccurate to use for
| much of anything. I built a force-feedback sensor for it out of
| a 3D mouse. Reasonable idea, but not stiff enougn for the
| application.
| mattlondon wrote:
| Holding a water pistol to shoot at foxes in my garden might be
| useful. They other humane deterrents (ultrasonics etc) don't
| work.
| cocoflunchy wrote:
| You don't really need a robot arm for this though... Also on
| my list of projects for cats :)
| mattlondon wrote:
| Future proofing for when they evolve into flying foxes!
| You'll need the extra degrees of freedom
| eichin wrote:
| From over a decade ago:
| https://us.pycon.org/2012/schedule/presentation/267/ (with
| just a pair of motors to point squirt gun at specific
| angles.) One of the (many) cases where a robot arm would be
| more _general_ without being in any way _better_ :-)
| boffinAudio wrote:
| Roboexotica is screaming for a set of these arms to create a
| production line:
|
| http://roboexotica.at/
| euroderf wrote:
| Drinks mixer! Line up the booze bottles and other stuff.
|
| No need for brute strength. Tolerances of one or two
| millimeters are mostly fine.
| Ekaros wrote:
| This actually sounds to me as bit complicated. As you need to
| adjust angle for each pour from a bottle. And then there
| might be different viscosities involved with some bottles...
| euroderf wrote:
| Angle would benefit from visual recog - shape of bottle
| top, shape of bottle body.
|
| Viscosities - probably finding a booze's sugar content
| online would be 90+% of it.
| fransje26 wrote:
| > but are there any practical home uses others have found for
| robotic arms? Hacking is always more fun with a good project.
|
| A reader of this thread that had a temporary disability posted
| some ideas about practical uses:
|
| https://news.ycombinator.com/item?id=39903953
| MaxikCZ wrote:
| I want the arm to wander around my house, pick up articles of
| loose clothing and put them into washing machine. Then pull them
| out and spread them on a drying hanger. How far away from that
| are we?
| pulse7 wrote:
| It has been here for several millennia... it even has two legs
| to walk around and two rotating cameras connected to a very
| powerful LLM...
| yjftsjthsd-h wrote:
| Nah, that model is expensive and buggy, not to mention closed
| source.
| melagonster wrote:
| but it work. I can't believe that we choose from different
| robots.
| Ekaros wrote:
| Depends where you live... In some places those models are
| entirely affordable. But likely will also there get less
| and less affordable.
| seniorivn wrote:
| most of those are trained on a very flawed data, so in
| order to use it for anything non trivial, you will have
| to invest a lot in fine-tuning, maybe even to an extent
| to call it training
| imtringued wrote:
| https://youtube.com/watch?v=HaaZ8ss-HP4
|
| A decade at most?
| cocoflunchy wrote:
| Not so far for the first part: https://wholebody-b1.github.io/
| fragmede wrote:
| That's it, isn't it. The question is not, how far away from
| that are _we_ , but when can you and I actually afford it?
| Because, as the other commenter snarkily replies, human maids
| already exist. The lifestyle of the singularity is already here
| for the rich. It's trickling down that kind of lifestyle to the
| rest of us that AI robots will enable. (with some amount of
| social upheaval.)
|
| Lets say the robot that can do that comes out next year for $15
| million. Could you afford one? I certainly can't. So pretend
| that it does, what changes for you and I? Nothing. So the
| robots that can do that won't be used as robot maids until the
| price comes down. Which; it will. Open source robotics and
| model-available AI will force things to be affordable sooner,
| rather than later, because we'd all like a robot to do that for
| us. Along with be in the kitchen, doing dishes, cleaning up;
| cleaning the bathroom, doing yardwork, making my bed.
|
| The industrial versions will be used to do hideously dangerous
| things. underwater welding, chainsaw helicoptering, manual
| nuclear reactor rod removal. We already use machines for a lot
| of those difficult/impossible tasks, it's just a matter of
| programming the robots.
|
| Which takes us back to today. How far away from that are we?
| The pieces are already here. Between https://ok-
| robot.github.io/ and https://mobile-aloha.github.io/ the
| building blocks are here. It's just a matter of time before
| someone puts the existing pieces together to make said robot,
| the only question is who will be first to make it, who will be
| first to open source it. Who will make it not just possible,
| but affordable?
| hatthew wrote:
| I think even more difficult than making it affordable will be
| making it _reliable_. OK-Robot says it has has a 1 /3 failure
| rate, and takes ~20x as long as a human, at which point you
| might as well do the task yourself. I'd want the error rate
| and speed improved by an order of magnitude before I'd
| consider it anything other than a fun novelty.
| dandaka wrote:
| AI technology is advancing at an exponential rate
| currently. The inquiry remains whether there's a limit to
| these technologies' potential.
| hatthew wrote:
| And as your error rate decreases, it gets exponentially
| more difficult to decrease it further. My guesstimate is
| that even ignoring the hardware issue, it would be at
| least a decade until we get AI capable of reaching human-
| level performance in household object manipulation
| (across a big enough class of household objects to be
| significantly useful in multiple tasks per day).
| IshKebab wrote:
| Define "we". Professional SotA? Probably like 10 years. Open
| source? More like 100.
| TaylorAlexander wrote:
| Google X was working on that with Everyday Robots (I used to
| work there) but they canceled the project. One of their old
| project leaders left and started Hello Robot, which is doing a
| much better job producing an actually useful thing. I think
| those robots are maybe $25k, but I'm not actually sure.
| 7373737373 wrote:
| Perhaps you could ask Twitch Chat to do that for you:
| https://youtu.be/uzWNgoYJLqM
| sebastiennight wrote:
| Let's look at the economics.
|
| In the US or Western Europe, a human worker would cost you
| about $12-$15 per hour (depending on the actual city and
| whether they're paying their taxes).
|
| You're looking at roughly 4 hours of work per 100 square meters
| (the average housing size[1]) per week to get the listed
| activities done, plus some general cleaning.
|
| So let's call it $60 per week or $3,000 per year. If we
| estimate the average useful lifetime of such a robot at 5
| years, they'd need to cost less than $15k (unadjusted for
| inflation) to make sense.
|
| This does not take into account that the house owner also would
| be paying for a small portion of the societal cost of this
| additional unemployed houseworker. If we assume that there are
| roughly 1 maid per 500 citizens[2] and that each unemployed
| worker costs roughly $20,000 to the State per year[3] then our
| back-of-the-napkin math says the robot worker is generating a
| socialized cost of $400 per year per household member (2.17
| members on average).
|
| So... we need a ~$14,132 fully-automatic, solar-charging bot
| before your dream can break even.
|
| [1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8073340/ [2]:
| https://www.statista.com/statistics/1087472/number-maids-hou...
| [3]: https://blogs.alternatives-
| economiques.fr/gadrey/2016/06/19/...
| samatman wrote:
| It's unreasonable to assume that reduced demand for home
| cleaning would translate one-for-one into unemployment and
| welfare. The bottom of the labor market doesn't work that way
| at all.
| spxneo wrote:
| You have to tradeoff between privacy, automation and cost.
|
| The scenario you described is tough to solve because of edge
| cases sort of like FSD.
|
| If you want that work done then its cheaper to hire a maid. It
| would be nice to have complete privacy and have a robot perform
| all those tasks flawlessly but the price point would make it
| economical to get a human to do it.
|
| Perhaps you can get someone to drive the robot but that puts
| privacy at risk.
|
| Same thing with sex robots it is cheaper to hire a sex worker
| so until something that can get us past the uncanny valley I
| don't think we will see a robot revolution quite yet. The
| hardware alone is prohibitively expensive and there is not
| enough people tinkering at the problem (because to hire humans
| is always safer and easier and cheaper).
| sebastiennight wrote:
| You're not going to get "complete privacy" (aka fully-offline
| local-model-driven) robots outside of building one
| yourself... There'd be just too much of an economic incentive
| to use this as a data collection platform.
| ipsum2 wrote:
| Does anyone have any suggestions on something that's a little
| higher quality, i.e. more torque and larger, like the size of a
| UR5 but cheaper than $30k? There's always seems to be a gap
| between "robot arm with dynamixels/off the shelf servos" and
| "research-grade arms".
| antoniuschan99 wrote:
| I have a dobot mg400 but there are quite a few others:
| uFactory, elephant robotics, annin, dorna, epson (vt6L and
| their scaras), and lynxmotion is releasing their ses-v2.
| ipsum2 wrote:
| Wow, thanks for the list of resources. My problem with most
| robot arms are either they have small payloads, accuracy
| isn't very high, are too slow, or software support is
| terrible. Do you have any specific suggestions for 6DoF? The
| MG400 looks to have 4.
| antoniuschan99 wrote:
| Mg400 is great for the price no issues. Very smooth! Check
| out this review video:
| https://youtu.be/6nGexb_i0aM?si=IP0E76MCGxrTrQEH
|
| What payload are you looking for? Cartesian Gantry's are
| your next bet if you want to handle higher loads. Eg. Epson
| vt6l is ~14k but I'm sure you can build a gantry system to
| handle higher loads for a bit less!
|
| Dobot software sucks though, I ended up programming it in
| python. It's definitely not on the same level as say a Kuka
| or Yaskawa. Epson seems like the best value out of all the
| higher end arms. Software looks good, the arms are built
| well, has a long history in industry, and price is decent
| numpad0 wrote:
| You don't want a cheap && powerful && fast robot in your
| home! Let alone sell a bunch of.
| dosssman wrote:
| Probably not UR5 size, but Aloha robot arm sounds like
| something you might be interested in:
| https://www.trossenrobotics.com/aloha-kits
| ipsum2 wrote:
| Thanks for the link, I would categorize this robot as "robot
| with off-the-shelf servo".
| moooo99 wrote:
| I'm not sure as far as your technical requirements go, maybe
| Igus.eu would fit your needs? They do have a fairly good robot
| automation portfolio that seems to be very price competitive as
| far as I can tell
| ipsum2 wrote:
| Their rebel cobot looks really neat, and price seems great!
| TaylorAlexander wrote:
| I'm very happy with the mechanical design for my four axis
| brushless motor powered robot arm with integrated 3D printed
| planetary gearboxes. I have some hope of picking the project
| back up and better documenting it, though the CAD files explain
| a lot. For the last few years I've been working on my own
| brushless motor controller design and I think this year I will
| have that stable enough to go back to working on this arm.
|
| https://github.com/tlalexander/brushless_robot_arm
|
| https://github.com/Twisted-Fields/rp2040-motor-controller
|
| Direct link to a video of it operating (apologies for the
| Twitter link) here:
| https://x.com/tlalexander/status/1455339851734138880
| coryrc wrote:
| Pretty neat! As a fellow motor controller designer, I worry
| you're wasting time reinventing the wheel in that regard, but
| I really like your project, I also want a farming robot.
| TaylorAlexander wrote:
| Thanks. I specifically want something that is designed in
| kicad, open source, and easy to manufacture at JLCPCB using
| parts already in stock there. Maybe there are more options
| now but two years ago when the Odrive we were using was
| discontinued and their new products got more closed source
| and more expensive, we didn't have a lot of options. At
| this stage I'm very happy we've gone with our own design
| because we have so much flexibility on packaging and
| specification. Working with third party devices sucked.
| ipsum2 wrote:
| This is awesome! I don't have enough background knowledge to
| know how to make one myself, do you ever plan to sell these,
| or make a tutorial on how to build one?
| TaylorAlexander wrote:
| Thank you! I do not plan to sell these arms. I am not sure
| if I will be able to make time to document it (I am
| maintainer on an open source farming robot project which
| takes up most of my time - see profile), but I am working
| on a new actuator concept based on the principles explored
| in this design, and my goal with the new actuator concept
| is to document that and make it more general purpose, so it
| is easier for people to make themselves and explore this
| mechanical gearbox design. This should hopefully popularize
| this design if others like it. I think is fair to say the
| design is probably novel.
|
| A fun fact about the new actuator is that it can be printed
| in plastic at home but is designed to be 3D printed in 316
| stainless steel. I was inspired recently by the relatively
| low cost of 3D printing from China (I used craftcloud), and
| my novel actuator design relies on the fact that 3D
| printing allows gearbox components and robot frame members
| or components to be mechanically unified. This opens up new
| design spaces.
|
| In this design, it is a two stage planetary with one "first
| stage" in between two parallel second stages. The first
| stage is driven by a shaft from a side mounted motor, with
| the shaft going through the gears in one of the second
| stages to reach the first stage sun gear. This parallel
| output better balances mechanical loads across the joint
| both on the input and output sides. This makes it ideal for
| elbow and knee style joints, and might serve to be
| genuinely very useful in robotics worldwide.
|
| As with all my work it will be open source. I don't love
| twitter but that is currently the best spot to get updates
| on side projects like this. I am @tlalexander there.
| Alternatively, star the 3D printed robot arm repo and I
| will update it when my new steel servo design is done!
| SirWart wrote:
| There are a couple of arms commonly used in research around the
| $10k mark, namely the Franka Emika and UFACTORY xArm 6.
|
| The ALOHA project uses the ViperX 300 6DoF, which is around
| $6500 but uses higher quality dynamixels with aluminum parts
| and bills itself as "research grade". I have one of these and
| I'd say it's expensive for what you get, but still cheaper than
| the "factory grade" robots. I will need a bimanual setup
| eventually and I'm probably going to get either an Emika or
| xArm since I'm already hitting the weight limits of the ViperX.
| hyperswine wrote:
| wow, thats really amazing. Are you a hardware engineer?
| gnarlouse wrote:
| This is fantastic! Thank you so much
| cs2818 wrote:
| As a longtime Dynamixel user I agree the U2D2 adapter is pricey
| in comparison to other options, but I would like some
| quantification of the "latency is very high" claim. I have always
| found it to be a sure bet for low latency (~1ms) across a wide
| variety of platforms.
| alexanderkoch wrote:
| It works fine with Linux. The latency issues only exists with
| macos. https://forum.robotis.com/t/u2d2-high-latency/5319
| omeze wrote:
| Im currently waiting on the motors for this, but my bambu p1s
| printed out the parts with minimal stringing in like 90 mins.
| Really to try it out for cooking experiments
| jack_riminton wrote:
| Is there a video of it working anywhere?
| alexanderkoch wrote:
| I've published quite a few videos on Twitter:
| https://twitter.com/alexkoch_ai
| NeilSmith2048 wrote:
| its really cool!
| 7373737373 wrote:
| I'm surprised (or perhaps very unaware) that there doesn't seem
| to exist a company yet that mass produces cheap, high quality,
| reasonably standardized robot arms. So many things like 3D
| printers or CNC machines have entered the consumer/amateur level
| price realm, but this seems to be something still largely
| unexplored. Seems to have Arduino/Raspberry Pi scale potential,
| but I haven't heard of a name/ecosystem that popular yet
| regularfry wrote:
| There have been a few around, but the limiting factor (as you
| can see from the BOM in the link) is the cost of the actuators.
| They get expensive fast.
| hackable_sand wrote:
| I was looking at electroactive polymers (EAPs) and I could
| not find a single company with consumer pricing...
|
| I wish there was more visibility here without requiring a
| PhD.
| FeepingCreature wrote:
| If they don't have to move fast, could you DIY an actuator
| with a stepper and a threaded shaft? Steppers are pretty
| cheap thanks to 3D printers.
| RobotToaster wrote:
| There are arms using steppers and 3d printed epicyclic or
| cycloidal drives.
| FrojoS wrote:
| For a useful robot arm, you need high forces/torques.
| Usually, this is achieved by high ratio [1] gearboxes
| between the motor and the joint. Those are expensive, and
| inefficient and make estimating the output force via the
| motor current almost impossible.
|
| [1] In the order of 1:100, see e.g.
| https://www.harmonicdrive.net/
| FrojoS wrote:
| Sensors too. E.g. force sensors are important for dexterous
| manipulation and safety. But they are all expensive, bulky,
| imprecise, or require constant recalibration, or all of the
| former. Our robotics Prof used to quote his industry peers:
| "The best sensor is no sensor."
| iLoveOncall wrote:
| Skimming through this threads and the various answers to the
| multiple "has anyone found a use for a robotic arm?" questions
| will explain why there's no such company. There simply is no
| consumer-grade market.
| 7373737373 wrote:
| A lack of applications hasn't prevented the sale of a large
| number of Arduinos lol
| moffkalast wrote:
| You can use an Arduino for virtually anything though. A
| robot arm can only move stuff around.
| JKCalhoun wrote:
| Arduinos are also $20.
| moffkalast wrote:
| Arduinos are like $3 if you buy Chinese replicas with the
| old bootloader ;)
| HeyLaughingBoy wrote:
| $20 will get you a 32-bit processor (ESP32), with Wi-Fi
| and Bluetooth 5.0 built in and a 2.8" color TFT screen,
| programmable with the Arduino IDE.
|
| $3 will get you a basic Arduino Nano clone.
| 0xEF wrote:
| Arduinos are for prototyping, which makes the application
| fairly massive. The company I work for used them to develop
| one of our machines before we moved to a custom board. So,
| I'd say they are pretty useful.
| 7373737373 wrote:
| Agreed, they certainly can be/are useful (and fun!), in a
| multitude of ways, but all too often I've also
| encountered peoples' "complaints" that they bought a
| bunch and now don't have a use case for it/are searching
| for one :)
| taneq wrote:
| That's because a toy engineering project is still an
| engineering project and will be way more work than you
| think it is, no matter how much work you think it is.
| It's hard to maintain that energy for long when it's not
| your day job (sometimes even when it is, tbh).
| HeyLaughingBoy wrote:
| LOL. I often tell people online that they're better off
| downloading the free Arduino IDE or playing around with
| the Wokwi simulator until they have a good idea of what
| they want to build and whether or not it's within their
| capabilities before buying parts.
|
| I've built a _lot_ of custom arduino-based projects for
| other people and a substantial fraction of them are the
| "I bought a bunch of stuff, but I don't have time to
| learn how to program it" types.
| f1shy wrote:
| Come on! They are for tinkerers!!! Same as such a robot.
| adaml_623 wrote:
| I don't think we've figured out how to make good cheap
| mechanical actuators. I think that engineers make do with
| inaccurate actuators by changing the mechanism around it. Robot
| arms need a level of reliability that isn't cheap yet.
| Ekaros wrote:
| Also I have understood that robot arms are in real life rather
| complicated to program to operate correctly. So any process
| would take substantial effort. Magnitude harder than
| controlling some relays or reading some sensor data.
| TomK32 wrote:
| Wouldn't be the easiest way to program a robot to "show" it
| its task by simply moving the arm a few times in the paths it
| has to replicate afterwards?
| amatic wrote:
| In a controlled environment - where the object to pick up,
| for example, is always in exactly the same location - you
| could do that. If there is any variation in the location of
| the object, you need vision to localize it each time. You
| need a camera, maybe two, and probably some kind of 3d
| perception, which is an unsolved problem at the moment
| (well, not solved in a general way, there are some
| solutions for specific objects).
| ska wrote:
| Yes, they have systems to learn this way, but it assumes
| the environment is controlled (always) and the task
| identical (always).
|
| Lots of automation works this way, but it actually limits
| the applications quite a bit.
|
| A robot that can safely work along side people (i.e., a
| "cobot") and adjust to environment changes and changing
| work patterns is a whole different beast.
| jfoutz wrote:
| I don't know, but I think the big real industrial kind can
| really really hurt or kill people.
|
| I think the limiter on smaller arms is quality servos with
| real location encoders - this one costs a couple hundred
| bucks for motors.
|
| Not claiming the software is easy! But I think sourcing parts
| is (or has been) really hard.
| KineticLensman wrote:
| > I don't know, but I think the big real industrial kind
| can really really hurt or kill people.
|
| Not a robot arm, but I worked on a project where the
| customer wanted to use a commercial motion platform as part
| of a simulator-based training system for boats. They
| thought they could just put it in the corner of their boat
| shed and get training but were amazed when they realised
| how dangerous it could be to passers-by, especially if it
| moved unpredictably when someone was standing nearby
| without paying attention. It went from 'we just need some
| crowd control barriers' to a full metal cage that was also
| integrated with the building fire alarm system so that it
| would stop cleanly if there was some sort of emergency
| elsewhere.
|
| Other motion-platform-based hilarity ensued when it was
| discovered that the commercial software model they were
| using to drive the sim could in some circumstances capsize
| the virtual boat.
| ectopasm83 wrote:
| I've explored the idea of using super cheap servos to build
| a robot arm/tentacle to pick cherry-tomatoes and it seems
| the only reason you'd want to use location encoders is in
| tasks that require high precision in an open-loop system
| (the robot is blind to its environment but has info about
| his own body). To me it seems you can get rid of this
| requirement if you allow the robot to sense its environment
| using cheap, 800x600 cameras with depth estimation ML algos
| and get away with the accumulated imprecision of sequential
| servos by coupling to each servo a high accuracy/small
| angle servo (just modify the servo's gear box). As for the
| gripper mechanism, you don't need fancy force sensors, just
| use a kirigami effector [1]. See also mobile-aloha [2].
|
| [1] https://www.youtube.com/watch?v=UerxNyu147g [2]
| https://mobile-aloha.github.io/
| ska wrote:
| > cheap, 800x600 cameras with depth estimation ML algos
|
| This typically won't be accurate enough for closed loop
| kinematics, especially at any sort of speed.
| ska wrote:
| > I don't know, but I think the big real industrial kind
| can really really hurt or kill people.
|
| Many medium sized arms are quite capable of generating
| forces that can kill a person.
| RobotToaster wrote:
| I think the main issue is inverse kinematics and path
| planning.
|
| Which is partly why SCARA is popular with amateur robot arms,
| the maths is simpler.
| ectopasm83 wrote:
| Forward and backward reaching inverse kinematics:
| http://www.andreasaristidou.com/FABRIK.html
| Itschris48 wrote:
| - Arm wrestling a toddler? - Handwriting notes for small
| jewelry brand? - Drink mixer? - Handing towel when in the
| bathroom, then getting a new one? - Setting up my morning
| espresso? (grinding the beans and turning on the coffee
| machine)
|
| Which of those can/cannot be done and why?
| michaelt wrote:
| _> Arm wrestling a toddler? _
|
| The most common designs of six-axis robot arm don't have the
| 'rotate forearm sideways' joint needed to arm wrestle.
|
| _> - Handwriting notes for small jewelry brand?_
|
| Possible: https://en.wikipedia.org/wiki/Autopen
|
| _> - Drink mixer?_
|
| Possible: https://www.makrshakr.com/ (arguably more of a
| showy entertainment item than anything else)
|
| _> - Handing towel when in the bathroom, then getting a new
| one?_
|
| Manipulating flexible materials is difficult. As is
| navigating through a house with locked bathroom doors and
| suchlike.
|
| _> - Setting up my morning espresso?_
|
| Depends if you're willing to broaden your definition of
| 'robot' to include bean-to-cup machines.
| jodrellblank wrote:
| > " _Arm wrestling a toddler_ "
|
| Like arm wrestling a brick wall; if you can push it over then
| you win, if you can't push it over then you lose - either way
| there's not much fun in it. And if it can beat the toddler it
| risks injuring them because neither of them really understand
| what's happening and what the risks are. The arm can't stop
| if the toddler says 'ow'.
|
| > " _Handwriting notes for small jewelry brand?_ "
|
| Can be done already with a commercial 2D plotter:
| https://www.axidraw.com/ . It costs twice as much as this
| arm, but you don't have to build it and it already has
| "software for realistic handwriting" and there's a company to
| get support from.
|
| > " _Handing towel when in the bathroom, then getting a new
| one?_ "
|
| Is the arm big enough to be useful for that? It appears to be
| shorter than a typical human arm so it would be cheaper,
| simpler and quicker to put the pile of clean towels a foot
| closer to the shower where the robt arm is sitting, and not
| have the robot arm at all. Plus you wouldn't have to deal
| with electricity in the bathroom or dripping water on the
| robotics as you reached for the towel it was handing you.
| (Are you thinking of a robot arm with cameras for feedback of
| where it's positioned? Cameras in a bathroom won't be popular
| with everyone no matter how much you promise they are
| innocent).
|
| > " _Setting up my morning espresso? (grinding the beans and
| turning on the coffee machine)_ "
|
| Simpler and cheaper done with a timer mains plug which you
| can get for under $10. Put the beans in and load up the
| coffee machine the night before (work you'd have to do
| anyway) and have the timer start them in the morning. If you
| expect the robot arm to unseal a bag of coffee beans, measure
| some out, deposit them in the grinder, close the grinder, and
| close and seal the bag after, you'll wake up to spilled beans
| and unsealed bag a lot of days before you get that working
| reliably. Instead of $250 plus weeks of effort to speed up
| this 2 minute task(!) you can get a Keurig / Nespresso pod
| coffee maker for less than $100.
|
| > " _Drink mixer?_ "
|
| How much spilled wasted alcohol, plus time of disassembling
| and cleaning your robot arm and the surface it sits on, and
| the floor, or finding the bottles, unscrewing the tops,
| handing them to the arm, waiting for the arm to slowly pour
| them which you could have done quicker, then putting the tops
| back on and putting the bottles away yourself, then putting
| the drink stirrer into the arm, then waiting for it to mix
| the drinks which you could have done yourself quicker, before
| you decide this was not a good use of time or money? (How
| often do you drink mixed drinks anyway?)
|
| The robot isn't going to learn to do the task better next
| time like a human could so if you have to get involved in the
| task _at all_ , you may as well do it yourself. And if it's a
| 15 second task like "reaching for a towel" what are you doing
| with your life trying to automate that? Roomba saves a lot of
| time, a lot of annoyance, it could be worth it even if it
| does an inferior job - because you can leave it running over
| and over and over. Same with a robot lawnmower, if you just
| glance around to make sure there's no pets or children in the
| way then let it go, it can save you a good chunk of time and
| if it goes wrong you just get a patchy lawn or dusty floor
| and it can retry tomorrow. But handing you a towel or mixing
| you a drink saves you almost no time, but if it goes wrong
| you get a broken bottle of sticky drink all over or a pile of
| towels on the floor, which has undone months of 'time saved'
| in one go.
| sebastiennight wrote:
| I like how this comment is clear, comprehensive, full of
| common sense,
|
| AND very likely to be completely outdated within a few
| generations (5 years?) of robotics + AI progress.
|
| I would also not discount how easy it is to sell people on
| additional cameras in their homes (including the bathroom)
| for the sake of convenience.
| jodrellblank wrote:
| State of the Art public robot arms include Boston
| Dynamics' Stretch[1]. It's not for sale to the public,
| the price isn't public, it's got 18 suckers on a flat
| tray and runs on a wheeled base and looks like the size
| of an armchair. Boston Dynamics' Spot the walking dog
| robot was launched in 2020 for $75k and was explicitly
| not safe for use in the home or around children.
|
| Do you genuinely think they will improve to the point of
| having finger style grippers, dexterity and adaptability
| to grind coffee, mix drinks and pick towels, and be on
| sale to the public, safe for use in the home, for $250
| (or $2500) by Jan 1st 2030? I would be very surprised.
|
| (Can you get a robot arm today, for any price, to help a
| quadraplegic open their mail, bring a drink with a straw
| in it to their mouth, lift them into a sitting position,
| hold a book in front of them and turn the pages, or ...
| do anything helpful? I'm not aware of any, but haven't
| been looking specifically).
|
| Yes you could probably build a robot today which hands
| you a towel from a pile, reliably and swiftly, or selects
| the bottles of alcohol and opens them and pours and mixes
| a drink - in a carefully controlled and lit environment
| where none of the lids or corks are stuck and the glasses
| are all a similar shape and size and nobody is allowed to
| be near it - I don't say it's impossible with today's
| tech, but it would cost a lot more than $250. A hundred
| or a hundred thousand times more, while being far far
| more limited than a human.
|
| [1] https://arstechnica.com/gadgets/2022/04/boston-
| dynamics-stre...
| jodrellblank wrote:
| After watching the Mobile ALOHA video linked in another
| comment, I'm increasing the probability of me eating crow
| on this one.
| ska wrote:
| > outdated within a few generations (5 years?)
|
| Hardware generations are typically closer to a decade
| than a year. Robotics is moving _fast_ these days, but
| not that fast.
| RecycledEle wrote:
| There is a reason there is no standard hobbyist-grade robotic
| arm.
|
| People think they can build their own robotic arms for leas
| than a "real" robotic arm costs, but the do not account for
| wobble or repeatability.
|
| With all due respect to the person who posted a design for a
| robotic arm made with RC servos on HN, I would like
| measurements of the repeatability. Have it draw the same
| pattern on a piece of paper every day for a week. Show me how
| closely the 7 lines overlap. I doubt that it can draw such a
| thing; it will tear the paper or get jammed without the
| strength to tear the paper.
|
| Source: I've been building hobbyist robots since the 1980's,
| researched robots in the 1990's including a masters thesis, and
| teaching robotics for most of the last decade.
| swalsh wrote:
| Why are you so negative towards this? It's just an Open
| source project... who cares how good it is. It's a great way
| to learn, and play, and experiment.
| f1shy wrote:
| That post is in the category ,,all knew it was impsossible
| until some stupid with no idea made it"
|
| That somebody was 4 decades failing, does not mean that at
| some point it won't be possible. In the last 4 decades the
| prices have lowered and the quality is much better in the
| RC world, if you know where to buy.
| RecycledEle wrote:
| > Why are you so negative towards this? It's just an Open
| source project... who cares how good it is. It's a great
| way to learn, and play, and experiment.
|
| I did not mean to criticize a hobbyist project for
| existing.
|
| I meant to say "There is a reason there is no standard
| hobbyist-grade robotic arm."
| LeafItAlone wrote:
| The hobbyist market is pretty forgiving of repeatability
| issues. The Ender 3 introduced many people (myself included)
| to the 3D printing world and is known for its problems.
| CakeEngine wrote:
| Is this not something that can be addressed with cameras and
| (maybe) learnt approaches now? You don't need blind
| repeatability if you've got good visual monitoring to close
| the control loop, you just (just!) need good accuracy and low
| latency from video to motor control.
| kaibee wrote:
| Why not just throw a SteamVR/Vive laser tracker onto the
| end of the arm and use that to close the loop? They claim
| sub-mm precision at room-sized distances, so it should be
| even better if you had it basically mounted on the base. If
| you wanted to get fancier you could build it into the end
| effector w/ one of these? https://tundra-
| labs.com/products/tl448k6d-vr-system-in-packa...
| taneq wrote:
| Horses for courses. Nobody's going be trying to weld car
| chassis with one of these, true, but also a hobbyist wouldn't
| want some ABB or FANUC or whatever industrial arm in their
| house where it could kill someone. These small light duty
| less-rigid robot arms are fine for what IMO is the really
| exciting stuff like modern machine learning control research,
| which is exactly what this guy's doing with them.
| ectopasm83 wrote:
| https://github.com/adamb314/ServoProject
|
| ^Modifying cheap servos so that a robot arm can repeatedly
| insert a pencil lead. It's a lot of work though.
|
| Most interesting application though fall out of the scope of
| old-fashioned robotic arms, i.e. when you need to sense the
| real world in a non controlled context. For instance to
| develop a robot that can trim wilted flowers, you'll need to
| measure the real world, and as soon as you do that, you can
| just sense your robot arm too, no need for fancy, ultra-
| precise actuators.
|
| Look at this BOM: https://docs.google.com/document/d/1_3yhWjo
| dSNNYlpxkRCPIlvIA...
|
| Do you really need the $6,129.95 & $3,549.95 robot arms for
| the kind of application described ? I doubt it. I'm not a
| robotician, and would love some feeback on this idea.
| mportela wrote:
| > cheap, high quality
|
| Most mechanical things require you to optimize for cost or
| quality
| mglz wrote:
| They do, but cheap is ~10.000EUR currently for a general-
| purpose bot with 1.2m reach. You get a high quality machine and
| software for that. Note that a robot without really good
| kinematics software is borderline unusable. Also, besides the
| arm you need the control box which reliably delivers power and
| commands in real-time. That adds quite a bit of cost too.
| leoedin wrote:
| I worked for a startup developing robot arms for a while. What
| we found was that giving someone a robot arm - even one with
| reasonable APIs and no cost to them - didn't really help
| because the hard part is making useful automations. Mostly
| people spent a few hours playing with the arm and then put it
| on a shelf.
|
| Every use case is completely different and is a lot of work.
| Even when you get something working, accidentally shake the
| desk or crash the arm into something and all your coordinates
| are broken and you have to start again.
|
| Not to mention the actual mechanics are really complicated - to
| have a meaningful payload at 50cm reach you end up with really
| high torque at the base joints (which also need to have super-
| high accuracy), which requires expensive gears and motors. None
| of that is cheap.
|
| Then you get to safety - an arm that has a useful payload is
| also quite heavy, and having that amount of mass flailing
| around requires safety systems - which don't come cheap.
|
| It's a bit like hardware no-code - you can't make an easy to
| use robotic arm because programming it is inherently hard. I
| think the only thing that will change that is really good AI.
| zafka wrote:
| In Robotic assisted surgery, Tracking targets are mounted on
| the robot arm and an infrared camera tracks the exact
| position.
| idiotsecant wrote:
| Yep. Interestingly, there has been a lot of recent work on
| models like RT-2 that might be capable of automating this for
| simple tasks. We might be at the point soon where that
| startup would have been viable!
| polygamous_bat wrote:
| AFAIK RT-2 doesn't quite work outside of Googles micro-
| kitchen, where they collected about a 1000 hours of data.
| idiotsecant wrote:
| That's how prototype tech often work : not very well. But
| its a proof of concept. A general model is probably not
| terribly far off.
| dansitu wrote:
| It's cool to hear from someone with experience!
|
| Do you know if anyone has tried building an arm that uses
| spatial positioning techniques from augmented reality, like
| structured light or pose tracking[1], to understand the
| position of the arm in space without resorting to "dead
| reckoning"?
|
| It seems like that kind of approach would increase the
| physical tolerance and reduce the programming complexity,
| since you know both a) where the arm is supposed to be, and
| b) where it actually is.
|
| [1] https://en.wikipedia.org/wiki/Pose_tracking#Outside-
| in_track...
| ska wrote:
| This is actually pretty common. But getting enough
| resolution to improve on what you can do with the encoders
| isn't so easy.
|
| The more usual application of multi-camera setups etc. is
| in path planning and scene understanding, not low level
| control.
| huytersd wrote:
| A six axis CNC machine is essentially a robot arm without an
| elbow.
| Johanx64 wrote:
| Ask yourself - what problem are you trying to solve? After
| you've defined it, you'll quickly learn that there's much
| simpler and cheaper solution than 6DOF robot arm in almost
| every case. And if you actually do need it, in those cases
| you'll find that 10-20k is actually pretty cheap all things
| considered.
| hawski wrote:
| With my understanding 6DOF robot arms are used when you need
| to be flexible. Today you do this tomorrow (or in a couple of
| months) you will need to do something else. The more diverse
| set of things to do the better. But if you need to do the
| almost exact same thing many times over for a long time it is
| better to design a production line that doesn't use 6DOF
| robot arms at all.
| ska wrote:
| > at there doesn't seem to exist a company yet that mass
| produces cheap, high quality, reasonably standardized robot
| arms.
|
| These do exist, it's just that "reasonably cheap" is typically
| low - mid 5 figures for any sort of reach an payload.
| SSNLF wrote:
| It's cool but just reminds me of the robotic manipulation episode
| of big bang theory.
| rini17 wrote:
| Why not start with something less ambitious, like low cost robot
| platform able to follow people and carry stuff around and avoid
| obstacles. No arms, I am okay using mine to put stuff on and off
| it.
|
| When I had leg injury and used crutches, carrying stuff around
| suddenly became a problem. There are many people with impaired
| movement. And even without that, I often misplace things and it
| could help there.
|
| There are plenty of toy robot undercarriages on aliexpress but
| too small (under 20cm largest dimnsion) to be practical.
| MattHeard wrote:
| i was going to ask if turtlebot was too small for you, but
| thought i should check the price first so uh, yeah, i'm
| guessing you're thinking the 250 price point instead of the
| turtlebot's 1000+
| deelly wrote:
| > low cost robot platform able to follow people and carry stuff
| around and avoid obstacles.
|
| So, basically autonomous self-driving mini vehicle. Sompanies
| spend billions on self-driving cars with quite limited luck.
| penjelly wrote:
| that is because they run in a very different environment than
| an RC-size car in your living room would
| RobotToaster wrote:
| > Sompanies spend billions on self-driving cars with quite
| limited luck.
|
| That's in part because it needs to be very reliable to not
| kill people.
|
| If the worst that can happen is killing a garden gnome or
| running over someone's toes you can tolerate more error.
| eichin wrote:
| Yeah, a "small enough to kick out of your way" autonomous
| driving project is a one or two semester student project
| (if you're starting from nothing, Sebastian Thrun's old
| Udacity course was a good way to bootstrap through the
| algorithmic parts, then maybe watch James Bruton for
| "everything you could possibly imagine doing with wheels,
| motors, and an infinite supply of 3d printer filament")
| jollyllama wrote:
| 100%. Arms are hard. Mobility is hard. Mobile arms are double
| hard.
| rini17 wrote:
| No, rather a larger version of robotic vacuum.
| numpad0 wrote:
| Bellabot[0] comes to mind, there's also a startup doing Roomba-
| like bot that magnetically dock to specially designed shelves.
| Though, they don't sell for $250, so actual Roombas and ROS
| mods for "hoverboard" Segway clones[3] might be more cost
| effective.
|
| 0: https://www.youtube.com/watch?v=l1hQ5YTMJEw
|
| 1: https://www.youtube.com/watch?v=SdVglHOJgiA
|
| 2: https://github.com/hoverboard-robotics/hoverboard-
| driver/tre...
| adolph wrote:
| "Follow me" luggage exists
|
| https://www.aristavault.com/products/follow-me-smart-luggage
| eichin wrote:
| also https://piaggiofastforward.com/ "gita" (I'm not sure
| what the market is for _fashionable_ luggage-robots, but they
| 're definitely going after it...)
| xchip wrote:
| Please stop gluing 3 servos together and claiming you built a
| robot :D
|
| (servos motion is quite jerky, that is why they don't have a
| video showing off this "robot" operating)
| alexanderkoch wrote:
| Here are some videos of the robot moving:
| https://twitter.com/alexkoch_ai. The advantage of this robot
| arm design is that it's very lightweight. The XL330 motors are
| just 18g each. This makes it very suitable for teleoperation
| and robot learning.
| iiJDSii wrote:
| As someone a lot deeper into robotics I totally get this
| sentiment... But I also think it's good to encourage people to
| share the basics, look how many newcomers in this thread find
| it interesting and may explore it further.
|
| I wonder how smooth one could make a cheap servo-based robot
| arm operate with decent control algorithms.
| robmurrer wrote:
| obligatory shout out to Annin Robotics AR4. Here is my build:
| https://commandpattern.org/2023/03/19/ar4-robotic-arm-build/
|
| $2K USD. 2kg payload. millimeter repeatability (if you build it
| well :)
| iiJDSii wrote:
| Nice build! I always wanted one of those AR robot arms but I'd
| rather buy it off-the-shelf than assemble from scratch. I don't
| think anyone sells them pre-built though. This type of 'high
| level hobbyist robotics' is in a bit of business dead-zone
| unfortunately, as it's some combination of too small a market
| and not enough use cases to justify having a company around. Or
| maybe there's potential there but no one's thought of it yet.
|
| Btw I bet your arm's movement smoothness can be improved with
| some different deceleration rates. It was really fun watching
| it sort those beans!
|
| My research goal with one of these 'good enough' 1mm
| repeatability robots would be vision-guided adaptive control to
| complete tasks after seeing examples of them done via human
| manual control. Would be a really interesting ML/AI problem.
| Just need a reasonable hardware platform to get started. Right
| now I'm leaning more towards simple/smaller servo motors like
| in the OP of this post (plus there's the cost/time trade-off).
| robmurrer wrote:
| this is where my research is going. camera -> llm -> targets
| -> tasks -> ros2 arm :)
| mtreis86 wrote:
| I started working on a similarly sized arm. I've got a use-case,
| long time friends with a glass blower. I was thinking of using it
| to make faceted glass pendants. They've got a faceting machine
| but it is manually operated.
|
| The hard part is repeatability. You need tight tolerances and
| each joint in the arm adds inaccuracy the further you get from
| the base. If the base has 1mm of wiggle, the 20cm arm has 4mm
| wiggle at the end, and the arm beyond it has even more.
|
| You also, for faceting purposes, need much finer resolution than
| an ungeared servo will have. Gearing it is tricky because you
| want backlash to keep the join tight, but not so much that it has
| high friction when moving. You don't really want to use a worm
| gear because they're both slow and overly rigid. So a cycloidal
| gear is the best bet for the gears in the arm. You also need real
| servos with some amount of feedback because grabbing at glass is
| sketchy at best.
|
| I was estimating 1-2k build cost, bulk of that is in the
| gearboxes.
| flutas wrote:
| Uneducated in hardware, mostly a software guy for perspective,
| so I could be way off.
|
| Would using something like a stepper motor geared way down with
| a cycloidal gear box work for a situation like this? (in my
| mind) It would give you a very controllable and repeatable way
| to position, with the backlash handled by the gearbox mainly.
|
| Would love to know if I'm wrong though, like I said mostly a
| software guy trying to venture into hardware!
| mglz wrote:
| Servo + Cycloidal or Harmonic gears are usually the way to
| go, but to get them backlash-free is hard (or expensive, if
| you're buying). Once you got that down challenges include:
|
| * How rigid are the links between my joints? Plastic will
| wobble, metal is better
|
| * How heavy is my arm and how does that limit its movement?
| If you go for stiff metal castings, you add weight you need
| to move. The lever arm relative to the base can get really
| long
|
| * Motors are heavy! Ideally you can mount them towards the
| base, but then you need drive shafts or belts, which again
| add flex. (See KUKA arms which have motors 4, 5 and 6 on the
| elbow often)
|
| * How much payload do you need to move? 5kg is already
| challenging in ~1m arms and if you need to move it fast the
| problem gets even bigger.
|
| * Where do you run your cables? Internal is tricky to build,
| external can get you tangled.
|
| And so on. When approaching this you get a totally new
| appreciation for biological arms which arae _insane_ in most
| aspects except for repeatability. And on the software side
| you can enjoy inverse kinematics :)
| adolph wrote:
| Do you think there is a way to take out backlash with
| sensors and software? Something like how additive
| manufacturing systems can use accelerometers to smooth
| artifacts from motor movement. [0] Let's say two cheaper
| cycloidal geared motors running in opposition with a load
| cell between them to maintain the materially compatible
| force.
|
| https://www.klipper3d.org/Measuring_Resonances.html
| Gracana wrote:
| The problem with backlash comes into play when the
| direction of force on an axis changes. If you are
| applying force in one direction and all the backlash has
| been taken up, everything is fine -- any force you apply
| or movement you make will be transmitted to the tool like
| you'd expect. However, if you have to decelerate, or
| you've gone over-center, or the tool/load pulls harder
| than you're pushing, now you have to apply force in the
| other direction, which you can't do until you take up the
| backlash.
|
| If your axis has high enough friction, then nothing will
| move when your actuator is in the decoupled backlash
| region, so you can compensate by adding the backlash
| amount to your target position whenever you switch
| directions. But that means you need more friction than
| tool force, with bigger motors and drivetrain to
| compensate. It's often easier just to build a system with
| zero backlash, then you can focus on tuning for system
| rigidity/resonance (as shown in your link).
| mathiasgredal wrote:
| That was why OP suggested to have 2 motors on each joint,
| going in opposite direction. The problem with this is
| that you now have twice the amount of motors.
| Gracana wrote:
| Oof, I appreciate you pointing that out because somehow I
| got the first part and skipped that one. Yeah, I could
| see that working, but it sounds inefficient.
| mglz wrote:
| I don't want to say no, however it seems very hard to do.
| You get feedback about motor position via an encoder,
| which is usually located on the motors axis and not the
| output element. Since the motor axis spins a lot more,
| you get more resolution. Backlash happens on the output,
| so you could add a second encoder there (but now you've
| got more complexity + cost). An oldschool CNC solution is
| to add brakes to lock an axis out, but this makes your
| system less flexible and doesn't prevent backlash during
| motion. A more modern solution might be to factor
| backlash in to your motion software so that you tell the
| kinematic solver what compliance is acceptable in some
| direction.
|
| > Let's say two cheaper cycloidal geared motors running
| in opposition with a load cell between them to maintain
| the materially compatible force.
|
| This might work, but now you have twice the amount of
| motors.
| mglz wrote:
| One thing that is amazing about industrial robots is how rigid
| they are when at standstill. Breaking systems start to be a
| challenge too at high speeds and loads.
|
| And once you manage to get the hardware working, getting a
| kinematic solver to really _work_ is a massive challenge. Tons
| of edge cases, real-time feedback to handle and the need to
| balance usability with reliability. That 's where robot
| companies charge a lot, and rightfully so.
|
| Whenever you can avoid building a robot arm and replace it with
| simpler kinematics, you should. Hats off to you if you build
| that thing!
| boesboes wrote:
| Have you considered using belts and sprockets? They seem
| effective in 3d printers and pretty cheap
| Gracana wrote:
| Belts introduce elasticity that can be very difficult to deal
| with.
| ska wrote:
| There are lots of belt driven industrial robots. They have a
| different set of trade-offs and challenges.
| iiJDSii wrote:
| I've done similar projects in the past (robot arms pushing
| performance limits in the few thousand $ range), and I found
| pretty good results with stepper motors, and gearboxes with
| sufficiently low backlash. For reference, these designs got to
| approx 1mm repeatability with 2.5kg payload at ~80cm reach,
| meant to model a human arm somewhat.
|
| Here's some specifics if you're interested. Depending on the
| end effector payload requirements, a mix of NEMA34,24,17 can do
| this (bigger ones for earlier joints). You can go
| cycloidal/harmonic gears if you have the budget, otherwise each
| actuator (motor + driver + gearbox + shaft coupling) would run
| you something like $100-$200 depending heavily on supplier and
| exact requirements (+$50 or so for closed-loop systems). So not
| terrible on the price front. Then for the base joint you'd want
| some wider cylindrical gearbox that distributes the load across
| better.
|
| If you're able to work with a machine shop I think you can put
| together something really high quality. Here's some example
| design inspirations, some of them even better than what I
| described I was able to put together as a hobbyist:
|
| https://www.youtube.com/watch?v=7z6rZdYHYfc (this one is
| fantastic; a smaller and lighter version operated more slowly
| would have even less wiggle from the base)
| https://www.youtube.com/shorts/II8gdIXPgaE (this is more
| comparable to the OP)
| https://www.youtube.com/shorts/_x7P9eZCkVM
| https://www.youtube.com/watch?v=g9AfhqOd-_I (most professional
| one I've seen, and almost certainly this BOM would be under
| $3k, probably under $1k in China. In fact I'll go ahead and
| email these guys since this is so cool and I wonder if they
| sell smaller models)
| https://www.youtube.com/watch?v=iB2NAgfVjIs (definitely check
| out Chris Annin, American roboticist who imo makes some of the
| best open source low cost stepper motor robots)
| Climato wrote:
| I think about this regularly just don't have the time to pursue
| it:
|
| Couldn't you build your arm in Nvidia Omniverse by also adding
| feedback like a cheap hig resolution distance or angle detector
| and train an ml model to compensate it?
| GabeIsko wrote:
| Making and animating a 3D graphics robot arm is trivial
| compared to building it in real life. So not so much
| Omniverse, you would want to use a proper simulator like
| gazebo.
|
| But beyond that, the kinematics as well as the force dynamics
| for controlling a serial manipulator are very well
| understood. So there aren't too many gains to be made by AI.
| It is difficult to implement in software due to some tricky
| situations about the nature of motion planning.
| Discontinuities around orientation approaches in 6-DOF
| systems for instance. But widespread use of serial
| manipulators is proof that, although challenging, they are
| relatively solved. It is always interesting to watch an AI
| model or genetic algorithm do some path planning, but this is
| a pretty well trod area of research at this point.
|
| Now, when you want a robot to walk and pick things up at the
| same time... that is when AI becomes something to consider in
| order to figure out how the dynamics should work.
| Climato wrote:
| I meant to control single segments to compensate for build
| quality.
|
| 1 AI model per motor
| GabeIsko wrote:
| But motor and motion control isn't exactly so mysterious
| that we need AI for it. Inductance in electric motors can
| have some odd effects in the acceleration domain, but it
| generally boils down to a second to third order
| differential formula. Even when linking multiple together
| in a serial manipulator, the math is really well
| understood for modeling the motion output. Maybe there
| are some outputs to be gained implementing different
| drive trains in arbitrary circumstances, and monitoring
| how they fail and stuff like that. At that point you are
| really getting into the weeds of operations and
| maintenance more than actual motion control.
|
| The situation that arises into a very complex
| n-dimensional problem that you would want AI to search
| through is the coordinated motion of multiple actuators
| to achieve a very complex output. Like, picking something
| up of unknown weight, running while carrying it up a
| steep hill, waving it around while doing all this. We
| take it for granted as humans with brains that can
| perform all this stuff trivially, but it is extremely
| complex motion.
| app13 wrote:
| Omniverse is a simulation platform specifically designed to
| do things like train/test robotics. It's not a creative
| engine like UE or Unity.
| GabeIsko wrote:
| I'm not super familiar, but they say in the webpage that
| it is specifically for Universal Scene Description, which
| is formally for graphics. Although, after a quick google,
| it looks like they do have a simulation package which
| then runs on top of Omniverse (Isaac Sim?), so I guess
| that is Nvidia's robotics offering.
|
| My general experience with other commercial offerings for
| simulation... is not great. In my experience, people
| usually end up migrating to gazebo, but I have been away
| from the field for a while now so it could be different.
| It is probably a situation where Nvidia will have a few
| coporate clients that they prioritize, and you are on
| your own to get it set up if you aren't on that lists.
| Pretty normal.
| leptons wrote:
| I recently saw this video, using modified servo motors to
| reduce the wiggle...
|
| https://youtu.be/Ctb4s6fqnqo?si=XP0MS0cpjlK_LMQC&t=8
| jannw wrote:
| tight tolerances and repeatability is mostly a combined
| rigidity and resolution issue, which is functionally equivalent
| to a cost issue. Add more money. Unfortunately there is a point
| where programming and hardware costs is higher than a skilled
| artisan ... hence the profession!
| xg15 wrote:
| > _The hard part is repeatability. You need tight tolerances
| and each joint in the arm adds inaccuracy the further you get
| from the base. If the base has 1mm of wiggle, the 20cm arm has
| 4mm wiggle at the end, and the arm beyond it has even more._
|
| Could this be solved by software instead of expensive hardware?
|
| Some idea I had a while ago was to build an arm out of cheap,
| "wobbly" components for the large-scale movements, but then add
| some stages at the end that have a small movement range, but
| can be controlled very precisely.
|
| Finally, add a way to track the deviation of the tool's actual
| position from the desired position very precisely, maybe with a
| tool-mounted camera.
|
| Then you could have a feedback loop in software which tracks
| the tool's deviation from the desired position and uses the
| "corrective" stages at the end to counteract it.
|
| I'm not sure if this would work, however.
|
| (There is also the question how long the "counteracting" would
| take. It's one thing to "eventually" arrive at the desired
| position at the end of the path - e.g. for pick-and-place - and
| another to stay below some maximum deviation for the entire
| path, e.g. for etching or welding.)
| zetalemur wrote:
| Isn't what you describe a PID-controller: https://en.wikipedi
| a.org/wiki/Proportional%E2%80%93integral%...
|
| AFAIK that is the common approach to solve this problem, but
| it still needs _some degree_ of sensor accuracy?
| tomp wrote:
| > Could this be solved by software instead of expensive
| hardware?
|
| Yes.
|
| Imagine a human putting a screw in a hole. You don't follow
| the "optimal" trajectory, you adapt it on the fly, even do
| several quick trials to do it.
|
| Humans do it with a combination of vision, touch and
| planning.
|
| Each of these is currently still a _huge_ problem for AI,
| nowhere _near_ human level.
| ActorNightly wrote:
| Id consider it more a fundamental problem - lack of a way
| to introduce new data to a model without repeating training
| runs and waiting for the error to converge. Humans seem to
| have an understanding of things from a one-shot learning
| run (this is perhaps due to our vast experience with the
| world and ability to run simulations in our head, but a
| subset of that should be possible for ML quite easily)
|
| If you solve this problem, teaching a robot arm to be
| accurate should be pretty easy. You would just have
| stereoscopic cameras that map to a 3d world, and "program"
| in a trajectory of the object, and the model should use
| that trajectory to figure out where to move and how to
| compensate based on visual feedback.
| tomp wrote:
| No, I'm telling you, you're assuming way too much. The
| problems are lower-level
|
| _> stereoscopic cameras that map to a 3d world_
|
| The current state of the art for this is completely
| atrocious.
|
| Take a look at this _very_ recent research:
| https://makezur.github.io/SuperPrimitive/
|
| The idea that robots can "understand" the 3D world from
| vision is, right now, completely illusory.
| ActorNightly wrote:
| I basically agree, I dont think you understood my
| comment.
|
| If you look at transformers in llm, you have a input
| matrix, some math in the middle (all linear), and an
| output matrix. If you take a single value of the output
| matrix, and write the algebraic expression for it, you
| will get something that looks like a linear layer
| transformation on the input.
|
| So a transformer is simply a more efficient
| simplification of n connected layers, and thus is faster
| to train. But its not applicable to all things.
|
| For the following examples, lets say you hypothetically
| had cheap power with good infrastructure to deliver it,
| and A100s that cost a dollar each, and same budget as
| OpenAI.
|
| First, you could train GPT models as just a shitload of
| fully connected, massively wide deep layers.
|
| Secondly, you could also do 3d mapping quite easily with
| fully connected deep layers.
|
| First you would train a Observer model to take an image
| from 2 cameras and reconstruct a virtual 3d scene with an
| autoencoder/decoder. Probably through generating
| photorealistic images with raytracing.
|
| Then you would train a Predictor model to predict the
| physics in that 3d scene given a set of historical
| frames. Since compute is so cheap, you just have rng
| initialization of initial conditions with velocities and
| accelerations, and just run training until the huge model
| converges.
|
| Then you would train a Controller model to move a robotic
| arm, with input being the start and final orientation,
| and output being the motion.
|
| Then hook them all together. For every cycle in the robot
| controller, Controller sends commands to move along a
| path, robot moves, Observer computes the 3d scene,
| history of scenes is fed to Predictor that generates
| future position, which gets some error, and controller
| adjusts accordingly.
|
| My point is, until we reach that point with power and
| hardware, there have to be these simplification
| discoveries like the transformer made along the way. One
| of which is how to one shot or few shot adjust parameters
| for a set of new data. If we can do that, we can
| basically fine tune shitty models on specific data quite
| fast to make it behave well in a very limited data set.
| LorenPechtel wrote:
| But do you need AI? How about this for a screw-in-hole
| machine:
|
| Assuming the hole is in the Z plane: Camera in the X plane,
| observes the screw against a high contrast background.
| Camera in the Y plane, observes the screw against a high
| contrast background. The motors need not know their exact
| position, just be of controllable speed. As the screw gets
| close to alignment the speed on the motor is stepped down,
| it stops when it's aligned. When both cameras report that
| it's in position a motor in the Z plane pushes the screw
| towards the hole, stopping when a plunger next to the screw
| reports the correct depth.
|
| If you have to be concerned with the Z axis alignment you
| make the X and Y backgrounds striped, the alignment of the
| screw is measured compared to those stripes and it's
| rotated accordingly.
|
| This is how a human would handle it--we do not have
| anything like the motor precision to get the screw in the
| hole directly, but we can use our eyes to refine it without
| *needing* the motor precision. Reliably identifying the
| screw from the background is hard but this approach doesn't
| require *identifying* anything. You're just mapping the
| bounding box of the object of a very different color.
|
| If you have a large movement field and a high precision
| requirement you might need two cameras, the second with a
| much narrower field of view.
| guyomes wrote:
| Some research is actually done in this direction. In 2015, a
| paper showed how a robot can adapt to injuries like a broken
| leg [1,2].
|
| [1]: https://www.nature.com/articles/nature14422
|
| [2]: https://hal.science/hal-01158243
| brozaman wrote:
| I'm a software engineer myself so I don't know a lot about
| this, but there are a few patterns that are not far off of
| what you're describing. For instance:
|
| https://en.wikipedia.org/wiki/Input_shaping https://en.wikipe
| dia.org/wiki/Proportional%E2%80%93integral%...
| ska wrote:
| How many degrees of freedom do you actually need, and what
| reach? Those parameters (plus speed) drive a lot of choices.
|
| 1-2k build cost is tiny in this space. I've paid that in
| individual motors (specialized ones, to be fair).
| jononor wrote:
| What kind of manipulation is needed? If a 3 axis or 4d axis
| system can do the job, that is always much cheaper than a robot
| arm, for a given precision and load capacity.
| eutectic wrote:
| Is it not possible to compensate for inaccuracy, if you have a
| sufficiently precise measurement at the hand?
| Mbartu wrote:
| A $250 robotic arm is really a price consumers can reach. How
| does it perform in practical scenarios in terms of durability and
| precision? Is it functional?
| schneems wrote:
| Any idea how much weight this could hold?
|
| I'm wanting to manipulate a fan in my home gym with some eye
| tracking to get it to blow air on my face when I work out, but
| the fan is a few pounds.
|
| Alternatively: any hardware motor suggestions for such a project?
| leoedin wrote:
| Most of these robots will use servo motors - that gives you
| dexterity but means that holding any position requires constant
| holding torque - which means limited payload and a lot of
| wasted power.
|
| For a heavy fan (don't forget the reaction force from moving
| air too), you'd be better off mounting it on a some sort of
| bearing and just using a motor to turn it. That way the motor
| isn't trying to fight gravity all the time. The robot arm
| linked here using Dynamixel servos - you could just use one of
| them to spin a fan on a lazy susan. Much cheaper and less
| complicated!
| dekhn wrote:
| yes, a belt-driven lazy susan is the right answer here (for
| azimuth).
| mclightning wrote:
| this is why servo-powered robotic arms are not interesting to
| me at all. I want one with brushless motors and harmonic or
| planetary drive gearbox. unfortunately you cant build those
| under $750 as far as I have seen so far. that's putting aside
| the added complexity. but I will definitely build one some
| day. there are quite few opensource projects with that setup.
|
| I believe it offers higher torque, better precision and
| ability to just stick to a position with relatively low/or no
| power due to gearing-side resistance.
| spspeaker wrote:
| Why not: keep most weight off the arm by using a fan/compressor
| installed in the base and routing a conduit to the arm? Then it
| will only have to move the conduit, not the heavy motor.
| nerdjon wrote:
| I have zero idea what I am going to use this for, but the idea of
| having a robot arm has fascinated me since I was a kid and I am
| 100% going to start working on this this weekend.
|
| I think I could find some fun projects. I wonder if it could hold
| my microphone and it turn into an automatic microphone arm...
| ozten wrote:
| Impractical, but here are my kitchen use-cases: - Hold a hot pan
| and drip bacon grease into a jar - Hold "almost empty" bottles
| like olive oil upside down to drain them - Making dishes that
| require constant stirring over a long period (tapioca, risotto,
| etc)
| gertlex wrote:
| Hah! Not actually a robot... but I half suspect I could
| convince the that wife a fold-out arm with a modest clamp (that
| could rotate a bit if needed) at the end would be worth
| mounting to a wall along the kitchen counters for
| holding/draining various containers like your first two use-
| cases.
| ozten wrote:
| Julia Child's kitchen was famously functional with a peg
| board wall for quick access to hanging supplies. I could see
| her doing that!
| wedesoft wrote:
| Bought a Sainsmart robot arm because it was cheap and has 6
| degrees of freedom. I don't use it for anything serious though.
| It was just to practice some robotic programming.
| https://github.com/wedesoft/arduino-sainsmart
| tsycho wrote:
| Here's what I want to build:
|
| A rotatable, table-top round disc base, with a contraption to
| keep a mobile phone straight and stable. The stand itself will
| have 4 small unidirectional mics, to figure out which direction
| (after filtering for human frequencies, ideally) is the sound
| coming in. And based on that, it will rotate the phone to face
| that direction (continuosly).
|
| The use case is family video calls that I do frequently from my
| dining table (my whole family is sitting around the table, hence
| there is no one good spot to keep the phone). With this self-
| rotating stand, the phone will auto-rotate towards whoever is
| speaking.
|
| I can write audio-processing code, but I have no idea how to get
| started with the hardware. Feel free to steal my idea, but please
| share with me how you are building it. I just want this to exist,
| and I want to know how to build it for myself as a fun project.
| mbrameld wrote:
| An alternative would be a 360 camera and do the cropping in
| software. It has the advantage of being able to show multiple
| speakers at once.
| willy_k wrote:
| If you can write the code, it could be pretty straightforward.
| From a quick search, motorized turntables already exist, from
| $10-100, both with and without remotes. So you could either
| wire a controller into one, or reverse the remote's signals. I
| also found this guide for a DIY one[0], if that's your
| preferred route.
|
| [0] https://www.instructables.com/15-Motorized-Rotating-
| Display-...
| spxneo wrote:
| i just want a DIY robot arm (6DOF preferred) that can give me
| massages? is there a community around this?
| CTrabandt wrote:
| Does anyone have any suggestions on something that can be used to
| for threading a small needle with a very fine thread? Would need
| high accuracy and repeatability. Higher price would not be a
| problem.
___________________________________________________________________
(page generated 2024-04-03 23:02 UTC)