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Comment by breakpointalpha | Hacker News Reader

What jumps out at me is the $135 bill of materials.

What a time to be alive!

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/

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.

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...

I haven't looked too carefully, but I suspect those "needs to be strong" parts could mostly be cnc machined with an inexpensive hobby CNC like a 3020, from aluminiumn sheet/bar stock.

That's what I was thinking, too. All but one of those parts can be easily milled from flat plate. The yoke end is a bit harder, but yoke ends are cheap standard parts and there's probably an off the shelf solution. The ball joints they use are standard R/C car parts. Those are available in in a stronger form, nylon with a brass ball, for EUR 0.53.[1] It won't be hard to strengthen this design so it can do useful work.

[1] https://toni-clark-shop.com/Ball-Joint-for-M2-and-M3

Smiles from Detroit. I would look to press those parts, since most contact surfaces are potentially convex and variant-depth parts appear superfluous to requirements. With a shared punch and die you could pull the nest off a laser, press them all in parallel, and break them after the parallel press-forming. Should be cheaper than injection because the cycles can be faster, the material can be stronger, there's only one die, and the unload will be easier?

Yes. Here are very similar parts produced with a punch press.[1] In Silicon Valley. Or in China.[2]

This sort of thing is probably about $40,000 for the first part, $0.05 for each additional part. Designing and making the custom dies is expensive. Banging out the parts is cheap. Mass production works.

[1] https://www.petersenprecision.com/fine-blanking

[2] https://yonglihaomachinery.com/

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

https://m.youtube.com/watch?v=6pbgOmaBx34

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.

Woosh

oh....oh no....

I think the confusion stems from the fact that you're responding to a joke innuendo thread.

They just haven’t watched the Big Bang Theory episode with Howard and the robotic hand:

https://www.youtube.com/watch?v=OYryogNE8Ys

Ooooh. For _that_ application you better have either enough elasticity or reliable force/torque sensors and a good control in place.

...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.

Without repeatability, good luck tuning your robot to do anything reliable.

Real world isn't "reliable". If a robot can't correct for errors, it's not going to survive out there.

> ...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.

The bottleneck for general purpose robots is, and always was, AI.

We've been in a continuous AI breakthrough since 2022. In 2000, this kind of thing was nonexistent.

> 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?

It took me a a distressingly long time to understand this comment. I'm kind of concerned, and have vowed to get out more.

> upwards of $100 per 30 min

That is why I'm self employed.

Search for ‘teledildonics’ on YouTube for one of the most entertaining and comprehensive Emacs courses you’ll find on the internet.

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.

Would adding AnySkin to the finger tips work? ( https://any-skin.github.io ) ?

Depends entirely on the application I guess, but you'd get further for sure. Either way you are now confronted with more complex cable management and maintenance, and additional weight. You'd at least get around gravity compensation with that approach. Personally, I think you need a lot more sensors and complex sensor fusion to achieve acceptable dexterity to be useful outside of an industrial context and this comes at high costs

Maybe this could be an add-on option for the K-Scale robot that is coming out soon? They want $1k for a 5 finger end effector hand.

https://www.kscale.dev/

I can't wait for this to be put on a tall roomba base so it can clean my kitchen.

You haven’t accounted for the 3D printer yet.

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