Hand: open-source Robot Hand

296 vineethy 88 7/17/2025, 12:08:38 PM github.com ↗

Comments (88)

breakpointalpha · 5h ago
What jumps out at me is the $135 bill of materials.

What a time to be alive!

Animats · 3h ago
Feetech is selling actuators which are mechanically R/C type servos, but have a bidirectional computer interface allowing the control computer to find out what's happening at the servo.[1] This isn't new; Dynamixel has been doing it for over a decade. But not at this price point. This Feetech servo is $17, while Dynamixel units start around $70 and go much higher.[2]

The parts list has "need to be strong" for many of the small parts, but they are 3D printed PLA plastic. That's the low end of 3D printing. None of the videos show the hand handling anything.

So this is really the proof of concept model. If there's enough interest, someone could make the parts by injection-molding of something better, such as polycarbonate or glass-filled nylon. The total plastic volume here is so tiny that the plastic cost is negligible, and there's no reason not to use a high-quality engineering plastic.

Nobody seems to do hobbyist injection molding much. TechShop had a desktop injection molding machine, the CNC milling machines to make molds, and even Autodesk Moldflow to design them. But nobody used those tools. A few university maker spaces have similar machines. Because most of the world's plastic stuff is made by injection molding.

[1] https://www.feetechrc.com/

[2] https://www.robotis.us/dynamixel/

[3] https://makerspace.engineering.nyu.edu/machines/pim/

mionhe · 2h ago
Mold design is still difficult when the parts aren't dead simple. The software I've seen is okay with the simple stuff, but once you get even a little more complex you have to understand simultaneously how to design good parts for molding and how to design good molds, both of which are heavily dependent on the type of plastic you're using and the size of the press you have access to. Not to mention how to machine good molds from metal, which is a challenge all on its own due to surface finish and tolerance requirements (and weird geometry that makes the CAM choke...)

In other words, we're not really there yet to bring that activity into the hobby realm. But I hope that we're not too far away.

Animats · 2h ago
They're little linkage parts, mostly flat.[1] Some of those holes are bearings. None of those parts are hard to make, but they need to be strong. They could be made by CNC machining, or in quantity by injection molding, or stamping. But tiny working parts in 3D printed PLA will be too flimsy for that hand to do much work.

Totally fixable problem. Then this hand can go to work.

If this thing catches on, someone might sell an upgrade kit with stronger parts. The designer is already considering a servo upgrade.

[1] https://github.com/pollen-robotics/AmazingHand/blob/main/ass...

stefanka · 1h ago
It’s one of best designs I have seen, I admit. But for that price you cannot get absolute encoders outside the motor, reliable force/torque sensors (think picking up a strawberry), tendons (thread below). It might be too limited for research and real-world projects unfortunately.
jjangkke · 4h ago
Most hand related jobs upwards of $100 per 30 min

If this Robot hand can do those jobs we could see some industries take a hit

0_____0 · 4h ago
People have been making end effectors using hobby servos for ages. These servomotors are designed for use in an RC aircraft, they're light, cheap, and expendable.

Industrial needs care not about weight, care less about cost, and care a great deal about capability, repeatability, and reliability.

This is a cool project for a hobbyist but it's not meant to be a serious industrial machine.

Edit: what is with this thread? Lots of very generic positive comments here but not much thinking about what this is actually useful for.

johnmaguire · 3h ago
I think the confusion stems from the fact that you're responding to a joke innuendo thread.
stefanka · 1h ago
Ooooh. For _that_ application you better have either enough elasticity or reliable force/torque sensors and a good control in place.
trhway · 1h ago
They haven’t watched Big Bang Theory.
stronglikedan · 2h ago
> Lots of very generic positive comments here but not much thinking about what this is actually useful for.

How can you say that when the person you are responding to is talking about what this is actually useful for?

pwndByDeath · 3h ago
Woosh
0_____0 · 3h ago
oh....oh no....
ACCount36 · 3h ago
...that's how it was in year 2020.

What you're missing is: today, we're nearing the point where actual general purpose robots become viable.

Which means: the purpose of a robot is no longer to sit at a factory line and precisely execute the same exact motions on repeat 24/7. The purpose of the next generation of robots is to learn generalized behaviors, adapt to circumstances, and carry out circumstance-specific actions with active sensor feedback. Which means completely different requirements for effectors.

Which means: repeatability can go get fucked, for one.

stefanka · 1h ago
> ...that's how it was in year 2020

Humanoid robotics research was pretty popular in the early 2000s already, with remarkable, reproducible results not only in videos. It’s definitively more present in the media now.

lukan · 3h ago
Without repeatability, good luck tuning your robot to do anything reliable.
ACCount36 · 2h ago
Real world isn't "reliable". If a robot can't correct for errors, it's not going to survive out there.
MisterTea · 57m ago
> upwards of $100 per 30 min

That is why I'm self employed.

kakapo5672 · 1h ago
It took me a a distressingly long time to understand this comment. I'm kind of concerned, and have vowed to get out more.
delijati · 4h ago
mrbonner · 2h ago
You haven’t accounted for the 3D printer yet.
echelon · 4h ago
I can't wait for this to be put on a tall roomba base so it can clean my kitchen.
Brajeshwar · 6h ago
Here is what I’m more keen on, rather than the human-like robots that we are all expecting. For instance, I would like a wall-mounted or floor-standing multi-arm robot that serves as a kitchen assistant. One can add or reduce arms as needed/desired. It is custom-equipped with a fire extinguisher, thermometer, and the usual must-haves for a kitchen. It will hold the cutlery, plates, and other items as needed. It will also advise on the likes of, “No, salts usually go in a pinch, would you like me to add in just about 5 grams?”

Thus, similarly for the garage, the DIY table, etc. Just Arms would be good.

bredren · 1h ago
It slices, it dices...

Seriously, though. Vassar Robotics (YC company) has an arm kit available for order now. The original ship date for my order just got pushed back due to an upgrade in the camera spec.

It won't be able to hold knives (I don't think) but there are companies working to bring about your hoped-for wall arm right now.

thrance · 5h ago
Tbh I would rather not have computer-guided knife-flinging arms in my home, be them on wheels or fixed to the wall.
sroussey · 5h ago
I have a parrot (whose beak is sharp enough, thank you very much) that loves to grab a knife out of the knife block and spin around with it.

I have to put a towel over it though today he pulled the towel off and still grabbed the knife and was holding it up when I turned around.

0_____0 · 4h ago
Like a mischievous toddler with wings...
seanthemon · 5h ago
It's a well known fact that birds aren't real and you must be a target now.
goopypoop · 2h ago
perhaps sir would prefer… tentacles?
scotty79 · 4h ago
I always imagined robot hands hanging and sliding on rails under top kitchen cabinets.
mclau157 · 7h ago
Pollen Robotics and HuggingFace are doing a lot for robotics right now!
ge96 · 6h ago
Wonder if it will get adopted (huggingface robot) I noticed the eyes/cameras go behind the neck thing for sleep mode
agumonkey · 4h ago
Anybody knows of similar projects for exoskeleton or support devices?
lucidrains · 4h ago
agumonkey · 3h ago
thanks a lot
Joel_Mckay · 31m ago
Yes, it is a technology originally intended to make spacesuits less brutal on astronauts hand/wrist/forearm fatigue.

Last I checked, project was shelved in 2020 for various reasons. =3

TheAceOfHearts · 2h ago
Does anyone know what design considerations, if any, might've gone into deciding to have 4 fingers instead of 5? And what tradeoffs that entails?

I actually saw this posted a few days back on Twitter and had been wondering if there was any deeper consideration for the number of fingers. It seems like you save around $10 in parts by getting rid of a finger, based on the information in the BOM.

p_d_r · 1h ago
It looks like the width of the servos driving each finger makes a certain finger spacing necessary, and I bet five made for an awkwardly wide hand.
binsquare · 5h ago
The world is designed with humans in mind, it's great to see robotics evolve in this direction to take advantage of that!
baq · 4h ago
Literally the reason for all publicly traded robotics companies going up recently.
poly2it · 4h ago
Why was this downvoted?
FBISurveillance · 2h ago
Great stuff. So 2x$135 and I'll finally get my t-shirts folded for me in the laundry room.
ortusdux · 6h ago
I wonder if I have time to make one of these and then decorate it to look like Thing for Halloween!
SequoiaHope · 3h ago
Beautiful design and I love that it’s in onshape with an aliexpress BOM. I might build this!
fitsumbelay · 3h ago
I love that it's cartoon style -- 3 fingers and a thumb instead of four
amelius · 8h ago
Would it be possible to have tendons running through the arms, so the weight of the hand is reduced?
atrus · 7h ago
Will Cogley has had a few different designs with tendoned hands.

https://www.youtube.com/@WillCogley

https://willcogley.notion.site/

So, there are designs out there for that too!

stefanka · 7h ago
Most tendons materials are elastic. That lead to create calibration problems and require proprioceptive sensors in the hand
Symmetry · 3h ago
In practice force sensing is more useful than proprioception in most cases, at least for grasping. Generally you won't the dimensions of an object you're attempting to grasp anywhere near as well as you would know the shape of the hand you're using so a certain amount of underactuated compliance makes the job a lot easier.
stefanka · 1h ago
I agree. But even then elasticity had to be taken into account (and maybe even gravity), if the object is very delicate.
fusslo · 7h ago
Huh, never thought of that

I wonder if companies are experimenting with materials like UHMWPE for non-elastic, high strength-to-diameter tendons.

I dont know if you'd have to weld the dyneema to the anchor points, though

stefanka · 7h ago
Roboy used dyneema tendons if I recall correctly. Fluidic actuators is another option. IMO, additional sensors and sensor fusion are necessary but this will raise the costs and demand to control software significantly. We are researching humanoid robots for quite some decades now and these problems are easily underestimated (similarly to autonomous driving). I doubt we'll see them in our houses very soon.
fusionadvocate · 4h ago
The issue is not that these problems are easily underestimated, but that the researchers are very proficient at repeating the same mistakes over and over again.
stefanka · 1h ago
Or both …
imtringued · 7h ago
I think you're misunderstanding the essence of the problem. If you use tendons, you'll need a neural network in your control loop that can learn continuously so that it compensates rope stretch and changes in friction through wear and tear.

A lot of problems in robotics reduce down to continual learning. Essentially all system identification tasks become obsolete the moment you have a self learning system and yet we have an AI industry preaching that AGI is around the corner without this "crutch".

stefanka · 6h ago
Not to mention that they easily break and are annoyingly tedious to be replaced (I had to assist often enough on such "surgeries" in our lab)
stefanka · 6h ago
You don't necessarily need neural networks for that, there are more specialized function approximations that learn faster and enable life-long learning for kinematics/dynamics and extrapolate better than NN which are more general purpose.
amelius · 6h ago
You could add encoder patterns to the tendons, like stripes. And then use something like a mouse-sensor to track them. This is still much lighter than servos.

Another idea is to use an external camera or two and to track the fingers with a deep learning model. But this can become messy if other objects are in view. And it might also introduce more control delay in the feedback loop than a simple sensor.

stefanka · 1h ago
If space permits you should add absolute encoders in the joints. In a finger that’s likely a challenge. In an arm, that’s easy
spauldo · 3h ago
I would think pressure and angle sensors tied to a PID loop would suffice, but I'm not a roboticist.
stefanka · 1h ago
If you can get a feedback loop at the respective joint, then yes, this might be enough. In case of an arm (not this hand), you can often only observe the end of a chain, and then, that’s more complex
glitchc · 5h ago
This is great, but to make a comparable hand, we also need very sensitive sensors, at minimum pressure and temperature, across the entire surface area.
falcor84 · 5h ago
Absolutely, though I'd be ok with just pressure as a starter.
mandeepj · 7h ago
The bigger or biggest question is - how much weight it can lift? If we assume it can lift half a pound, then what changes it’d require to make it lift 10/20/30 pounds and so on?
micromacrofoot · 6h ago
hands hold, arms lift — a hand without an arm isn't going to have much strength
horsawlarway · 4h ago
Yes, but this is "bring your own arm" so the person above you can easily build the arm out to whatever specs they'd like.

They probably want to know relatively important information like

- Breaking force (how much force will break a finger)

- grip force (How much force can the fingers exert to hold an object once closed)

- holding force (combination of grip force and material properties [ex - friction] that gives you an idea how much force can be applied to prevent slipping)

- closing force (How much force is exerted during closing [similar but distinct from grip/holding])

Or, with a lot less specific detail but still generally useful as a starting point...

- payload capacity (approximately how much can this safely manipulate)

mft_ · 7h ago
This looks like a nice, approachable robotic model of a human hand that can be printed and experimented with.

But... is a human hand the best design for a robot to grip things with? Or could we surmise that the human hand evolved as a pretty good hand given the materials and senses that were available to evolve humans from, while in theory a totally different design might be optimal for gripping when constructed from metal, plastic, motors, etc.?

LeifCarrotson · 6h ago
A human hand is probably the most appropriate design for a robot to grip a variety of things that were designed to be gripped by human hands.

For any one specific thing, be it a doorknob, a rope, a sheet of paper or fabric, or a pair of scissors, there's probably a different design that's several orders of magnitude simpler and cheaper, and also much stronger and more reliable. Single-axis parallel grippers, circumferential chucks, vacuum cups/vacuum pads, electromagnets, cam lock and release mechanisms, and so on are common in industrial robotics.

Assume your robot's only task is to grab a spool with a 35 +/-0.5 mm ID core from from an infeed rack and place it on a spindle, you're not going to try to build a five-finger human sized servo-operated hand and tuck two of those fingers away to awkwardly pinch outwards from the inside, you're going to grab a Schunk JGZ concentric gripper off the shelf and plumb a pair of air lines to it. If it also needs to grab a tab from some tape on the spool and pull it into the machine, you're just going to add an asymmetric pincer like an angular tumor on two of the jaws - or graft on an entire separate parallel gripper like some polydactyl appendage, or tool-change, amputating and reattaching hands at will.

I have also observed that humans are quite good at anthropomorphizing robot arms: a small, well-tuned motion can be universally recognized as a nod of agreement, shrug of confusion, wave of acknowledgement, or sigh of disappointment, even if the equipment is a bright yellow 6-axis piece of cast iron with menacing claws where the hand (or face? they're often the same) should be. Googley eyes and a "Hi my name is" sticker make this even more convincing.

But if you need a single tool to grip a doorknob, a rope, a sheet of paper, a pair of scissors, AND an unknown variety of other arbitrary household objects... it's probably best to start with an approximation of the human hand. Also, while claws may be appropriate for a work environment with the robot inside a fence, in collaborative situations hands are just less intimidating.

Someone · 6h ago
> For any one specific thing, be it a doorknob, a rope, a sheet of paper or fabric, or a pair of scissors, there's probably a different design that's several orders of magnitude simpler and cheaper, and also much stronger and more reliable.

Also, if you’re designing a robot gripper for any one specific thing, it’s quite possible that you can tweak the design of that specific thing to make the task easier. As an extreme example, screws and screw drivers evolve in parallel.

turtledragonfly · 5h ago
As an aside, this "robot tentacle" paper was referenced in a recent HN story: "SpiRobs: Logarithmic Spiral-shaped Robots for Versatile Grasping Across Scales"[1]

Seems like a pretty high bang-for-the-buck for versatility and capability with only a few cables controlling it.

[1] https://arxiv.org/pdf/2303.09861

ctxc · 6h ago
Good point, well put.
TechDebtDevin · 6h ago
Would you prefer necrobotics!?!

https://www.smithsonianmag.com/smart-news/scientists-use-dea...

How long until human hands are put on robotics??

jimhi · 5h ago
This is the craziest thing I’ve seen in awhile
ygjb · 4h ago
The question you are asking opens up a whole other field of questions. The amount of AI and robotics "in the field" is only going to increase. As that increase comes do we want to continue to build for a human capabilities and limitations, or do we want to build for machine capabilities and limitations.

I think the ethical approach is to build for human capabilities and limitations. We have already seen what happens when we allow business to optimize for the lowest common denominator, and that is why we have regulations that emphasize accessibility. If we allow or encourage businesses to build robots that lack human capabilities and limitations that operate in the real world alongside humans, then even if those robots are assistive in nature (either a prosthetic robot hand, or a full blown humanoid robotic assistant), we will displace or redefine what humans are capable of, and diminish the role of and respect for human beings in our society.

hansvm · 6h ago
Among other things, the ability to pretrain for a task by just copying human motion is pretty powerful.
atrus · 7h ago
Depends on what you mean by best ofc :P

If anything, the human world is built for humans, so a lot of existing things are naturally compatible with human hands. Also, take into account flexibility. It might not be the best for one job, but it's really okay at a lot of jobs.

beAbU · 4h ago
The human hand is arguably the best general purpose gripper of human-scale objects. Only took evolution a couple of hundred million years to figure it out.

If you can limit the scope of things to be gripped, e.g. a sheet of paper, a baby chicken or a 100x100mm square steel girder then no doubt there is a better design out there.

eichin · 1h ago
Not exactly. The human hand is really advanced within the constraint of "you can't just arbitrarily replace damaged parts". If you can swap in replacement fingers, 3 of them is fine (and much easier to model and perform grasping calculations.)
magicmicah85 · 7h ago
Is there a better design? I ask this genuinely, I really don't know but I suspect that the human hand is versatile enough to allow it to be programmable for a variety of tasks.
a_wild_dandan · 6h ago
Our modern world was built for hand-havers, so we build hand-havers for general interaction with the modern world. This vicious cycle will end, but a certain amount of inertial clunkiness is inevitable in nascent technological disruptions. Especially in moments as grand as the second industrial revolution.
bigmadshoe · 7h ago
It’s easier for humans to train a human hand
espadrine · 6h ago
I agree that there are some robotic designs that unnecessarily mimic human limbs. I have in mind heads, and feet (instead of wheels).

A hand however, is useful because so many manufactured objects have been constructed for their purpose.

swiftcoder · 5h ago
Feet are used for roughly the same reason a human-like hand is preferable - human-designed spaces tend to not be perfectly compatible with wheeled locomotion.

The ability to negotiate stairs is table stakes for a household robot. It's already a pain when one's Roomba-like is defeated by a small ledge...

jjk166 · 4h ago
Well we aren't all wearing mecha-claws to improve upon our feeble human design.
mandeepj · 7h ago
You can make it switchable! Think of it more like a dye, if that helps.
numpad0 · 6h ago
Why should not we build robots that mimic us?
schainks · 4h ago
I swear I've seen this before somewhere..
ImPostingOnHN · 8h ago
Looks like this product is called AmazingHand (and there are billions of "hand"s in the world), so the title might have some room for improvement as far as searchability goes.

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