[HN Gopher] Launch HN: Vassar Robotics (YC X25) - $219 robot arm...
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Launch HN: Vassar Robotics (YC X25) - $219 robot arm that learns
new skills
Hi HN -- I'm Charles from Vassar Robotics
(https://vassarrobotics.com/ - not much there but you can order the
robot at https://shop.vassarrobotics.com/products/navrim-robot-
that-l...) We are bringing an upgraded version of the long beloved
SO-101 robot arms to a $219 price point with improved mechanical
design and added intelligence. See what it can do here:
https://youtube.com/shorts/xNyPKJZI400 (demos are sped up as shown
in the video) I've spent a few years building RC planes
(https://cyo.ng/hangar/) and micro gas turbines
(https://set.mit.edu), and I've always wished hardware were cheaper
so more people could experiment. I'm now launching a $219 desktop
robot-arm kit that keeps LeRobot SO-101's kinematics, swaps key
parts for sturdier, more precise SLA prints, and adds two
integrated 480 p cameras. After plenty of supplier haggling, the
whole kit costs less than the twelve servos alone. I'll release the
updated mechanical design under an MIT license by June 30. On the
software side, I'll also release an MIT-licensed MCP server by June
30 that exposes the local robot policy as tools for agentic LLMs
(Opus 4, o3, etc.) to use in long-horizon tasks. Here's how it
works: You can teach the robot new skills through teleoperation.
During inference, you simply talk to the agentic LLM using natural
language instructions. The LLM then calls the local robot policy
through MCP, automatically decomposing your high-level requests
into executable robot commands. Thanks to the LeRobot community
for making such an amazing robot accessible. If you've contributed
to the LeRobot GitHub repo, email hello@vassarrobotics.com for a
20% discount coupon as a small thank-you. I'd love your feedback!
Beyond manufacturing, cleaning up the codebase, and writing docs,
I'm considering: a force-controlled gripper, a parallel-jaw
gripper, an extra wrist DOF (matching the new Trossen and ARX
arms), full force feedback on the leader arm (though that may
triple the price), a more affordable version with lower resolution
each joint, and a longer-reach variant. Which of these--or
something else--would be most useful to you? You can order it here
if you want: https://shop.vassarrobotics.com/products/navrim-robot-
that-l.... Looking forward to any and all comments! --- Edit: A
quick explanation regarding shipping times (as stated on our shop
page): * The first batch of 20 units, which will be shipped by
June 30, is sold out. * The second batch of 100 units will be
shipped by July 15 (unassembled kits) and July 21 (assembled
units). The order limit is to ensure we can ship on time and
maintain high quality. For those who have already placed orders: I
will reach out individually to ask if you would like to receive
weekly progress updates from now until the shipping date.
Author : charleszyong
Score : 213 points
Date : 2025-06-10 19:12 UTC (3 hours ago)
| xchip wrote:
| Please don't call it a root if it uses cheap servos
| charleszyong wrote:
| We are using the same servos as SO-101 from Feetech
| xchip wrote:
| you are using $14 servos (STS3215), movements won't be
| precise... plus you are selling a robot that costs $121 for
| $200... See the original open source project here:
| https://github.com/TheRobotStudio/SO-ARM100?tab=readme-ov-
| fi...
| GordonS wrote:
| Wow! Recently my son has been asking about doing a project with a
| robotic arm, and this looks _amazing_ , especially at the
| hobbyist-friendly price point. And adding in AI is really cool -
| and just the thing to _really_ grab the attention of an eight
| year old boy :) Will these be available in the UK, perchance?
|
| A bit of an aside, but how hard is it to get into building RC
| aeroplanes, compared to FPV copter drones?
| bittercynic wrote:
| Planes, like quadcopters, are as complicated or simple as you
| want them to be. They're available fully ready to fly, as kits
| with different levels of work needed, or you can build from
| scratch and choose your own parts and design.
|
| Flying is pretty different, though. If you're used to a copter
| that will just stay put when you release the controls, flying
| planes will be an adjustment.
| charleszyong wrote:
| Yes yes! Flying an aeroplane has no pause button. You are on
| your own from taking off to landing. It's a great practice
| not to panic under stress (I never flew one but I guess
| racing FPV quadcopters probably has the same feeling)
| charleszyong wrote:
| RC aeroplanes need some practice and a bigger field compared to
| FPV drones. I think I spent a week flying in simulators and
| another 2 weeks crashing several times to get a basic hold on
| it. It's kind of like training a robot foundation model to
| learn a new embodiment
|
| That being said, I enjoyed every moment flying my planes. I
| built and flew quite a few quadcopters but they never felt that
| free because there's always that control algorithm between the
| pilot and the motors, while aeroplanes are basically just
| mapping the movement of the joystick to the servos. I believe
| the UK has a lot of great local clubs, and I believe that's the
| best place to get started.
|
| Side note, when your son gets more experience in the field, he
| might wanna build his own gas turbine to power his planes. And
| this association based in UK is the best on this planet:
| https://www.gtba.co.uk
|
| For UK delivery, let me look into how to set up international
| shipping. Will get back to you by end of the day.
| GordonS wrote:
| I hadn't thought about clubs, probably because I live in a
| small, rural Scottish town... but I just had a quick look,
| and incredibly there's an active club just a few miles from
| me, which I had no idea even existed!
| bri3d wrote:
| Building RC planes is a little harder IMO, but not much.
|
| The main difference in building planes is you have to pay
| attention to center-of-gravity much more; minute differences
| will make the difference between your plane flying amazingly,
| like a brick (nose heavy), or not at all (tail heavy). There's
| also more work to do in setting control linkages and surface
| throws. But, overall, it's not too tough with most models.
|
| Takeoff with planes can be very stressful the first few times;
| you have to choose between ground/runway takeoff, which
| typically results in a very inefficient model due to landing
| gear drag and is prone to flipping over, throwing the plane by
| hand, which requires practice and can be quite hazardous with a
| "pusher" style plane with the prop at the back, and building
| some kind of bungee launcher, which you then have to set up and
| lug around.
|
| Then you have to decide how to fly - line of sight or FPV. Line
| of sight flying is quite an acquired skill and has a very steep
| learning curve - you basically have to learn to "become the
| plane" and understand how your control stick inputs are
| affecting the attitude of the plane without being able to see
| it very well.
|
| FPV plane flying, while less popular than LOS, is very easy and
| much more rewarding IMO. The reaction time in all but the most
| extreme plane stunt flying is much less dramatic than in FPV
| quads.
|
| And, due to quirks of the general hobby flight control software
| scene, most hobby FPV planes have a working loiter-in-a-circle
| setting while most FPV quads have a barely-functional GPS
| rescue mode and little to no ability to actually hover (it's
| very rare for an FPV quad to "just stay put"; this is the realm
| of camera drones).
|
| I fly FPV quads when I need a focus/adrenalin boost and FPV
| planes when I just want to relax and chill. You can fly planes
| in an adrenalin style, but they're much more conducive to just
| looking at the scenery and goofing around. Massive bonus points
| that most plane builds are almost silent compared to an FPV
| quad so you don't worry about bothering people so much.
| bathMarm0t wrote:
| If the goal is the building. Balsa kits (an xacto knife, 2
| bottles of super glue [thick/thin], CA-accelorator) are the way
| to go. Discuss gliders are easy to manage the risk of learning
| how to fly, and are light, so crashes will only be mildly
| catastrophic. I have this one, and it was easy-ish to build
| (~20 hours?)
|
| http://wrightbrothersrc.com/products/gambler.htm
|
| If the goal is the flying. You can't go wrong with an easy
| star. I've crashed mine a million times. You just patch it back
| together humpty dumpty style with thick CA + accelerant. Bonus
| points for the prop being in the back, so if you run into stuff
| you (probably) won't draw blood.
|
| https://mrmpxhobbies.com/product/rr-easystar-3/
|
| Note that the hobby does require some skill w/ flying and need
| some level of risk management. There are cords that let you
| plug your transmitter into a computer/fly over a simulation
| that can help with the former.
| laidoffamazon wrote:
| Alright, watching the video - I'm sold, even at a sped up rate.
| How do I buy? I'll do in-town pickup if that's faster!
| pryelluw wrote:
| A link to the product page, please.
| charleszyong wrote:
| There we go: https://shop.vassarrobotics.com/products/navrim-
| robot-that-l...
| martythemaniak wrote:
| Neat! Does this work with open source models like pi0 and
| OpenVLA? How does the inference-time teaching you outline work
| exactly?
| charleszyong wrote:
| The software stack is built around LeRobot. So anything you can
| run with LeRobot should be able to run with our software. Will
| do more testing before the official release. Personally, I feel
| GR00T N1 or ACT is much easier to train and do a fairly good
| job
| mclau157 wrote:
| will there be options to use GR00T N1 or ACT in the future?
| fragmede wrote:
| How backportable are the upgrades? If I have an SO-101, can I
| just replace a few parts to mount a camera and use your software?
| charleszyong wrote:
| The software is fully compatible with LeRobot's repo. As long
| as your dataset matches your inference time setup, you are good
| to go.
| rohitpaulk wrote:
| Where do I buy one?
| lucidrains wrote:
| Love to know as well!
| timmg wrote:
| https://vassarrobotics.com/
| dang wrote:
| Link added above :)
| timmg wrote:
| Funny, I was just about to build an SO-101, but tariffs adding
| $100 to the price of the servos annoyed me.
|
| How do I buy your kit, please?
| echelon wrote:
| Their website has it! I think I want one too.
|
| https://vassarrobotics.com/
| fragmede wrote:
| Need more videos, especially at 1x speed.
| dang wrote:
| This one shows the chess bit at 1x speed (at least I think so):
|
| https://www.youtube.com/watch?v=TbDTCwzFeIU#t=52
|
| (I timestamped it to skip the initial voice dialog with the
| robot but that might be entertaining for some people as well)
| fragmede wrote:
| damn, nice. that's quite the video!
| tomp wrote:
| I've been looking for a cheap 7 DOF arm. The only reason I
| haven't bought SO100/101 yet is that it's 6 DOF (and that
| delivery to Europe is hard to find..)
| Ninjinka wrote:
| Love how instantly recognizable the default NextJS app is
| iamflimflam1 wrote:
| Interesting - I was just thinking the other day that a well
| implemented MCP server driving a robot with access to a camera
| could be a really interesting project.
| timmg wrote:
| And now I am too!
| Nevermark wrote:
| I love the arm/typewriter "printer"!
|
| It's not exactly on topic (other than fun ideas, begetting fun
| ideas), but a USB-C/WiFi driven typewriter would be a hoot.
|
| EDIT: Found [0]
|
| And for the reverse ... boom! (click! clack!) [1]
|
| [0] https://www.nutsvolts.com/magazine/article/turn-a-
| typewriter...
|
| [1] https://www.usbtypewriter.com
| asadm wrote:
| neat! what camera module did you guys settle on.
| dataminded wrote:
| Enjoy my money!
| lchengify wrote:
| I wonder if I can strap this to my Roborock from 2020 and train
| it to pick up socks.
|
| Roborock sells a new model that does this [1] but it costs $3,000
| and I refuse to pay that on principle when I know it's likely a
| straightforward model with some unsupervised training.
|
| Also I can probably fix it easier once it (definitely) breaks at
| some point due to collisions.
|
| [1] https://www.youtube.com/shorts/vHVQxXVgBm4
| yardie wrote:
| Of course this arrives right after I order all the electronic
| parts and just kicked off the 24+ hour 3D print job to complete
| my SO-Arm101.
|
| But I'm routing for you!
| charleszyong wrote:
| Thank you! Let me know how you like the SO-101 design. If you
| have complaints, I might be able to find a way to fix it ;)
| icedrift wrote:
| Literally same. Just finished printing the leader arm and not I
| have another 20 hour print for the follower.
| loxias wrote:
| Firstly, at the $219 price point you can have my money already.
|
| Beyond that, things that appeal to me are basically anything
| which increase the likelihood I can accomplish high dexterous
| fine motor control skills, for things like tinkering and DIY
| assembly. I think that would include extra wrist DOF and a
| longer-reach variant.
|
| Integrated cameras are an interesting idea, but I'd like to be
| able to swap them out for my own.
|
| My dream is to have some sort of multi-arm table at home. I
| imagine holding a circuit board, small component, soldering iron,
| and wire with four robotic arms I control with shaky hands from
| my laptop. :D
| charleszyong wrote:
| So true. Every time I solder surface mount components, I always
| wish I could have a steady hand. Sadly, this arm doesn't have
| that kind of accuracy. The output shaft of the servos we use
| has about 1 degree of wiggle room and the mechanical structure
| adds more.
|
| To get better accuracy, if sticking with this kind of RC servo,
| it's basically required to have two servos per joint to preload
| each other to kill that wiggle room. It's something I've been
| calculating, but I just can't figure out a way to offer it at a
| good price.
|
| Interestingly, for arms that are popular in academia, even when
| the price goes to $10k (like ARX or Trossen), the wiggle room
| is still there (better, but still there).
| fragmede wrote:
| even something twice the price ($438) would still be a great
| deal. Mind telling us something about your pricing strategy
| trade-off consideration matrix?
| charleszyong wrote:
| Design for manufacturing is one thing. I did it a lot when
| building micro gas turbines in college. Sometimes changing
| the design or manufacturing process will make it 10x faster
| to make one while not compromising the performance.
|
| The second thing is low margin. When people are pricing
| hardware, they usually plan a 50% to 100% margin to offset
| various costs that happen in the real world. From what I've
| heard, in extreme cases, some products cost around $100
| while they are being sold at close to $1000. I believe in
| the Prusa printer approach: you design a good product and
| price it a little bit above cost. So the company grows with
| the community.
|
| Deep down, there are so many times that I wish I could
| afford a fancy tool like a Milwaukee drill or a Mitutoyo
| caliper. And in extreme cases, I really wish I could have a
| HAAS UMC-400 or even a KERN Micro HD+. Now that I can set
| the price, I really wish I could make someone get what they
| want without breaking their bank.
| fragmede wrote:
| that's really great, thanks for sharing!
| tdeck wrote:
| For folks curious about why these kinds of margins are
| built in for hardware products, I found these videos
| informative:
|
| https://www.youtube.com/watch?v=UwrkfHadeQQ
|
| https://m.youtube.com/watch?v=IdAT_SIRK8c&pp=QAFIAQ%3D%3D
|
| https://m.youtube.com/watch?v=63pnz-z_2sU&pp=QAFIAQ%3D%3D
| tdeck wrote:
| I was recently trying to get better angular accuracy with
| servos and minimize backlash. One option that kind of worked
| was to have a pulley on the servo shaft which wound a string
| attached to a spring to add mechanical bias.
|
| But I ended up giving up and going with 400 step stepper
| motors instead. They're larger, draw more current, and the
| drive circuitry is more complicated (it can't get simpler
| than a PWM servo after all). But they're accurate and
| significantly quieter.
| vasusen wrote:
| I love the idea of a trainable robot arm as a learning device at
| that price point.
|
| However, seeing the chess demo instantly makes me think of that
| horrible tragedy with the robotic arm breaking a kid's finger.
| How strong is this to be used around kids?
| charleszyong wrote:
| Yeah, safety is an important aspect. The good news is that the
| servos are not that powerful. Peaking at 3 Nm, with a moment
| arm of 0.2 m, you get 15 N of force, which is basically
| equivalent to the weight of three 500mL water bottles. This
| force might cause some scratches but should not lead to serious
| injuries.
|
| Initially, I was planning to launch a product using Piper Arms
| (much more powerful than the current product). But after
| testing them, I realized they could cause serious injuries if
| not used properly. So I canceled that version. I still have 8
| of them sitting in my office.
| benob wrote:
| I am seeing different prices everywhere: - $199
| https://shop.vassarrobotics.com/ - $219
| https://shop.vassarrobotics.com/products/navrim-robot-that-l... -
| $599 https://www.youtube.com/watch?v=TbDTCwzFeIU
|
| Which one is the actual price?
| bufferoverflow wrote:
| $199 was the Founder's edition, already sold out.
|
| $219 is the unassembled version.
|
| $299 is the assembled version.
| charleszyong wrote:
| $219 is for the unassembled version $299 is for the assembled
| version $199 is for the first 20 units of the assembled version
| $599 was the price before I spent hard hours dealing with
| supply chains
|
| When I was just a hobbyist, I had to pay the price on the
| website. Now that I have some funding to order in large
| quantities, prices come down a lot. I do the dirty work of
| sourcing the components so hobbyists don't have to ;)
| charleszyong wrote:
| Thank you for catching the mistake. I've updated the video
| descriptions.
| vavooom wrote:
| What a unique and fun build! So curious to hear about what ways
| it can be programmed and used for personal projects.
| mclau157 wrote:
| the website is pretty bad....could use a lot friendlier buttons,
| layout, more pictures, maybe some videos
| lysace wrote:
| Sometimes a lack of solid product photos/specs/etc is a
| feature. (To the seller.)
| peepeepoopoo135 wrote:
| Interesting project! Sorry if I'm out of the loop, but how
| exactly does the MCP server hand off visual data to an external
| LLM service to formulate the robot control actions? It's an
| interesting concept, but I'm having a hard time wrapping my head
| around how it works, because I thought MCP was text-oriented.
| codybontecou wrote:
| +1 to this. Curious how the MCP manages base 64 image-related
| data and the encoding + decoding.
| pj_mukh wrote:
| So cool!
|
| I would easily pay $1000-$1500 if you put two of these on a wheel
| base and made it all structurally sound. Extra points if the arms
| sit at least 1-2 feet of the ground and can reach the ground.
| GlenTheMachine wrote:
| You need some technical specs on the website. How many DOF does
| it have? Does it have joint angle sensing? If so, what's the
| resolution? What's the interface to the servos? What's the
| payload capacity? Does it have integrated motor controllers? How
| long is it, and what does the dexterous workspace look like?
|
| As a roboticist, what I'd vote for, in order, is:
|
| - more degrees of freedom
|
| - interchangeable tools, either an actual tool changer (unlikely
| at the price point) or a fixed bolt pattern with electronic
| passthroughs
|
| - better joint sensing, e.g. absolute encoders, joint torque
| sensing
|
| - fingertip force sensing
| rfwhyte wrote:
| As someone who's long dreamed of owning a robotic camera control
| arm, but who doesn't have a spare $50K kicking around to buy one,
| I've been following the development of these kinds of projects
| with great interest. While this particular arm doesn't look like
| it would have enough payload capacity or smooth enough motion for
| the use cases I have in mind, the fact its a couple hundred bucks
| means something that does what I need it to do for an actually
| affordable price isn't likely too far off.
| hbarka wrote:
| Can this be coupled with some kind of vision AI to open/close my
| doggie door when pup-pup wants to?
| mclau157 wrote:
| if this can be extended to full size doors this could be a very
| good business, no more need to modify doors to have doggy doors
| mlboss wrote:
| Opening a door is still a challenging problem for robots.
| Better to have electronic control of doors that can be opened
| programmatically.
| dheera wrote:
| The reality is nobody can afford houses anymore, everyone
| is renting, so modifying doors is usually not an option. If
| you can work with existing infrastructure without modifying
| it, that is marketable.
| aesch wrote:
| While I don't think this will ship in time. There is a global
| online hackathon using these robot arms on Hugging Face June
| 2025, 14-15. https://huggingface.co/LeRobot-worldwide-hackathon
| charleszyong wrote:
| Man, I gotta say that I tried really hard to see if I could
| ship before that, but I failed ;( Chasing suppliers is pretty
| much like dating: sometimes no matter how hard you try, you
| just can't make it happen.
| chrishare wrote:
| Well, hopefully you can find some suppliers you can settle
| down with and live happily ever after
| guywithahat wrote:
| You should put it on Amazon; we used a robotic arm in one of the
| classes I taught, and for logistics reasons it was basically the
| only way we could order stuff. Plus it helps with discovery.
|
| I'm sure there's an extra fee but it's sometimes just impossible
| to order things if you're a big organization from small sites
| like this.
| charleszyong wrote:
| Thank you for the suggestions. I hear you. When I was at
| college, the school system basically only allowed Amazon plus a
| few industry-specific suppliers. Please allow me to prioritize
| manufacturing and testing so that I can ship the product as
| soon as possible and with the highest quality possible. Then I
| will start expanding sales.
|
| Also, the servos we are using actually have a version that has
| lower torque/force output, which would be safer for students
| but also limit what they can do with it. Would you be
| interested in the "safer" version for classes?
| pama wrote:
| First world problems: can I email you and specify a later
| shipping date?
| _tqr3 wrote:
| As another robot hobbyist, I wish there were more detailed
| documentation on how things work. So many projects online just
| show a working demo--usually on YouTube--and it's impossible to
| decipher what's actually happening, or if the robot is simply
| following some predefined movements.
| whoomp12342 wrote:
| combine one of these with an automated robotic mower and have it
| pick weeds, then we are in business baby!
| aesch wrote:
| I'd be interested to hear about your experience working with
| suppliers. How did you go about finding suppliers and haggling
| with them?
| TuringNYC wrote:
| I've been looking for a robot arm for a while to play ping pong
| with me. Curious:
|
| 1. Would we be able to control it deterministically via an API,
| rather than relying on LLM?
|
| 2. What is the latency on this? Do you think it would be fast
| enough in deterministic mode to play ping pong?
| Javantea_ wrote:
| Can you compare your robot to Baxter? I'm curious to see how this
| works.
|
| Congrats on shipping!
| charleszyong wrote:
| Do you mean that Baxter by Rethink Robotics?
| https://en.wikipedia.org/wiki/Baxter_(robot)
|
| Thank you!
| pbrb wrote:
| Ordered. This is so cool. I also started looking at LeKiwi... I
| think I'm going to have to figure out how to make this thing
| mobile.
| polishdude20 wrote:
| Can you explain more how this is possible? For a layman like me,
| what is happening when you tell the robot to do something and how
| does it know it's going to the right place?
| dimitry12 wrote:
| SO-ARM101 has a leader-arm, which is the arm with same exact
| dimensions and same servos - but used to read/record the
| trajectory. You move it with your own hand and teleoperate the
| follower-arm in real-time. Follower-arm is visible in the demo
| videos.
|
| If you fully control the environment: exact positions of arm-
| base and all objects which it interacts with - you can just
| replay the trajectory on the follower-arm. No ML necessary.
|
| You can use LLM to decide which trajectories to replay and in
| which order based on long-horizon instruction.
| bredren wrote:
| I'm down to buy the kit and build but need some idea for how long
| it takes. Like, I was able to detail finish and assemble a 3D
| violin but could not make the time and space to assemble a full
| 3D printer and had to sell it.
|
| Would you please provide more info on what's involved for the
| kit? Ranges are okay.
| charleszyong wrote:
| Great question. I would say that the first time I assembled a
| SO-101, it took me about 3 hours to assemble and calibrate
| everything.
|
| This product is largely based on the SO-101. With all the
| improved designs, let's say it would still take 2 to 4 hours,
| depending on your experience.
| polskibus wrote:
| How can I order it to Europe?
| quadrature wrote:
| I'm curious about how the perception works, how do you find
| correspondences between the arm camera and the stationary camera
| ?
| joshu wrote:
| saw you guys setting up over the weekend! good luck tomorrow
| anythingworks wrote:
| really cool, hoping you're able to ship it in time, given the
| overwhelming demand
| charleszyong wrote:
| Good point. I've limited the orders to 20 units for shipping in
| June and 100 units for shipping in mid July.
| tdeck wrote:
| I love that you're open sourcing the design! Would be curious to
| hear your experience as you build and sell these.
| dimitry12 wrote:
| Do I understand correctly that chess-moving demo decomposes into:
|
| - you recorded precise arm-movement using leader-arm - for each
| combination of source- and target- receptacles/board-positions
| (looking at the shim visible in the video, which I assume ensures
| the exact relative position of the arm and chess-board);
|
| - the recorded trajectories are then exposed as MCP-based
| functions?
|
| Bought the kit. Thank you for the great price! Are table-clamps
| included?
| codekansas wrote:
| This is super cool! What have been your favorite and least
| favorite things about open source robots?
| charleszyong wrote:
| Favorite: git clone and start using (or spending a whole
| afternoon to fix environment issues) Least Favorite: some cool
| projects (especially in academia)--the results need H100s to
| replicate...
| cadr wrote:
| Just to check - do you ship from the USA? (international is
| confusing these days...)
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