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charleszyong

448 karma · joined October 25, 2021

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charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
For software support, the software is open source, so the community can keep it going even if we’re no longer around (hopefully not anytime soon).

For repairs, the components are inexpensive enough to simply swap in a new one, and you can always find replacements on AliExpress.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Dalton Caldwell: “Make a product people love; worry about making money later.”
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
NextJS (and Vercel) is really easy to use ;)
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
We will have a two-arm version available, as well as a kit for people to convert the current version to two arms—probably in August or September.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Yes, we 3D print and assemble in San Francisco, and ship from there.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
You can sign up for email notifications here: https://vassarrobotics.com/newsletter

It will probably be available in late July. We’re expanding the team, so we might be able to offer it sooner.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
I hear you, man. After using 7-DOF arms, there’s no going back to 6 DOF. I’ll try to develop a version and hopefully get it out in August.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
We’ll probably have an electronics-only kit available in late July. However, it won’t be much cheaper, as we’re running on a very thin margin.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Kuka had this demo years ago: https://youtu.be/tIIJME8-au8

Nowadays, if you’re running a 2–3B parameter foundation model on a standard computer, you’ll probably get a rollout frequency of 1 to 10 Hz. ACT would be faster, but I still don’t think it’s fast enough.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
I need to ship the current orders before taking the next batch, so it will probably be sometime in late July. You can sign up for an email notification for the next batch here: https://vassarrobotics.com/newsletter
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
XLeRobot and LeKiwi are both great!
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
The robot is only as good as the amount of time you’re willing to spend teaching it. If you put in, say, 20,000 hours and make "some" hardware upgrades, you can get it to do things like this: https://www.physicalintelligence.company/blog/pi05
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
I’m running on a very thin margin here. I want to get the robot into the hands of robot lovers without them having to eat McDonald’s all month just to save up for it. (I did that once myself, and I strongly advise against it—it’s really bad for your health, both physically and mentally)
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Very good suggestion! They look really promising. I’ll talk to the company to see if the price will be acceptable.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Interesting. Their servos seem to be PWM servos, which are available at a very good price. I would look into how to hook up all the servos—you’ll probably need an MCU to convert USB to PWM for each servo.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
The advantage of servos is that they can provide constant torque preloading, allowing the preload to be kept low (otherwise, the servo will overheat) but still sufficient.

A spring might also be an option if designed properly. I’ll probably give it a try in July.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Yeah… the accuracy isn’t good enough. A gantry system is probably needed.

There was one robot startup (Haddington Dynamics) figured it out how to do it at a higher price. Sadly they've been acquired and shifted directions I think.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Backlash is a real problem. I’m working with the supplier to prototype a small batch with 20 to 30% less backlash, though this may come at a slightly higher price and potentially a shorter lifespan.

If cost isn’t a concern, harmonic drives combined with brushless servos are excellent. I have a few harmonic drive units, and they’re truly amazing.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Thank you for your support! I’m actively working on the design and building the supply chain. In the next 3 to 6 months, I should be able to:

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.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
The servos we are using in the follower arms are capable of generating about 3 Nm of peak torque. This isn’t a lot of torque, and they can’t move very fast. If absolute safety is your top priority, you could opt for servos that use 7.4V and a low gear ratio, which would further limit their torque output. The consequence is that the arm will be significantly weaker.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Sorry for being MIA for a bit. All 120 units are now sold out. I’ve created a waitlist at https://vassarrobotics.com/newsletter to keep you updated on when the next batch will be available (most likely in late July).

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.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Which country are you in? I can set up the delivery option for your country.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Sure! You can email us at hello@vassarrobotics.com

As long as it’s within this year, I’m sure we can arrange it.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Yes. You are exactly right. If you want the model to have some adaptability, you will need to train a policy like ACT or GR00T.

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)

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
I’ve just set up shipping service to the UK. You should be able to place an order now. Let me know if you have any questions!
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Very good question. Currently, I’ve only sourced power supplies that meet US standards. However, I’m confident I can provide a power supply that works for Australia as well.

When you are placing the order, make sure you put the shipping address to Australia address and so that I will know I need to source corresponding power supply.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Thank you for stepping in. Yes, it’s 5 DOF and a gripper using ST3215 (12V for the follower arms and 7.4V—various gear ratios—for the leader arms).

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.

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Just to clarify, these improvements is for future models.
charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
Thank you for the feedback! Thinking out loud: • Adding one DOF to match ARX kinematics is doable, with a price increase of $30–40.

• 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?

charleszyong··on Launch HN: Vassar Robotics (YC X25) – $219 robot arm that learns new skills
For hardware, folding laundry with just one arm is really hard. So probably you will need a dual arm setup.

For software, even the best policy in the industry struggles a little bit (the arms they are using is about $10k each): - https://youtu.be/Oa19cq_MxE0 - https://www.dyna.co/research

In conclusion, for hardware, it might work if you have two of the arms; for software, it's probably too hard to collect enough data to make it work.

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