Edit: the entire run sold out thanks to HN today—thank you all! And sorry to anyone who missed out. You can get in on the next batch here: https://vassarrobotics.com/newsletter.
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.... (Edit: sold out! You can get in on the next batch here: https://vassarrobotics.com/newsletter. I hope we can have your business in the future.)
Looking forward to any and all comments!
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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.
Thank you so much for everyone’s support. My top priority now is to get all the orders shipped on time and with high quality.
$200 is a really nice entry-price point. If I'm being honest, I'm marginally interested in this, but doubt that I'd actually use it too much. But the price point is justifiable for someone who is just interested in it from a learning point of view (if I bought this, used it a few times and learned a bit more about AI as it relates to robotics, it'd have paid itself off easily).
Rooting for you to succeed.
1. Keep the price similar while adding new features, such as a torque-controlled gripper. 2. Re-examine design decisions to see if we can offer a similar product at an even better price.
And you've got an excellent gradient to keep growing!
All the best!
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
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).
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.
Couldn’t you preload with some form of spring?
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
• A tool changer is a great suggestion. A few of my friends are working on kinematic couplings, which would be ideal for this. I’ll need to give some thought to how to pass electrical signals and power to the tool, while also keeping it lightweight.
• Could you share what functionality you want in terms of encoders? The ST3215 uses 12-bit magnetic encoders, which can retain position after power loss. Are you looking for higher resolution? For torque sensing, if the order volume is large, I can add this for just a $20-30 price increase.
• Finger tip force sensing: Is this for applications like picking up an egg?
The post says "kit that keeps LeRobot SO-101’s kinematics" so it's probably very similar to [1] namely 5DOF and a gripper, using STS3215 servos [2]
> As a roboticist, what I'd vote for, in order, is:
As they are making a robot at the $219 price point, I very much doubt they have the money to add anything to the design.
[1] https://huggingface.co/docs/lerobot/so101 [2] https://uk.robotshop.com/products/magnetic-encoding-servo-st...
As for hardware features, we can’t add much to the current model since, as you mentioned, we are running on very thin margins. We’re gathering suggestions primarily for future models.
“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?”
But I’m routing for you!
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.
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?
I love the product though, and I appreciate your input!
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.
Just a quick difference I need to point out as it's critical product spec: leader arms are using 7.4v version of ST3215 (various gear ratios) while follower arms are using 12v version of ST3215. (12v version have higher peak torque at close to 3 Nm)
A bit of an aside, but how hard is it to get into building RC aeroplanes, compared to FPV copter drones?
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.
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.
I haven't built a balsa wood plane in ages. But so, the glue of choice has changed ? No more balsa wood glue with atrocious fumes ?
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.
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.