Could I pursuade you to expand on "Repurposed drone technology has done wonders for legged robots." ? Thanks!

For legged, you want high torque and backdriveability (for shock absorption).

Agricultural drone motors like the eaglepower 8308 are ideal.

They’re cost effective, (~$80 from aliexpress) & you can pair them with a 3d printed cycloidal drive to fulfill both requirements.

Industry actuators are an order of magnitude more expensive than this.

Extra: If you go down this path, you’ll need a driver. The Xdrive is frequently recommended, but there’s a clone that’s significantly cheaper: https://makerbase3d.com/product/makerbase-xdrive-mini-high-p...

thanks for the Xdrive pointer, I just got samples of tinymovr and odrive controllers (with FOC), they seem nice but are more expensive.

This is pretty cool, thanks for sharing. I wish there was a (mostly) 3d printable Cara mini, but I’ll start with Cara.

The layout is doable with hobby servos, but you'd need to patch in current sensing for that bit of the feedback. It's not terribly difficult conceptually but it's an extra complication that most servo power distribution boards don't give you.

You can also strap a capstan to the servo axle, if that's your thing. I've prototyped that myself in the past. You can go surprisingly far with an FDM printer, an SG90, and some dyneema bowstring. One thing I haven't tried is modding one for continuout rotation to get around the way the capstan drive limits the output angle you can achieve - I was happy reducing from ~180deg to ~45deg for what I was doing - but that's relatively well-trodden ground. Might pull that project out of the storage box it's languishing in at some point.

> The layout is doable with hobby servos

Mostly we're past that. Robotics with hobby servos sucks. Been there, done that, robot arm is in electronics recycling bin right now.

I agree it's not great but for scale and convenience it's good. If this was going to just get scaled down, what motors would you pick?

Motor: https://www.aliexpress.us/item/3256804897857573.html?gateway...

The 90KV version is what you want.

"The 90KV version is what you want."

You mean the "KV90 color" of course, ha ha.

That we live in an age where "agricultural drone" is even a word pairing…

Look at the original video/article, they used drone motors for the robot dog, by reusing the rotor/stator and rewinding the coils manually.

So it may still be cheaper for us to train junior engineers in the long run.

It more looks like the purpose of such company was to steal such data.

Look at their privacy policies. It absolutely is. They are harvesting video, voice, and much more.

I second this, personally I'm currently using French version of Khan Academy to upgrade my French (you just do something like fr.khanacademy.org). The French also have a lot of theoretic math resources available and it's what I vibe with at the moment. Whatever gets you to read, listen, learn.

Coffee is a plant demon that created the western civilization as we know it today...

I like this worldview. Prior to coffee, Europe was in the grip of the beer dwarves. Coffee demons took over and invented nationalism, capitalism and Keynesian economics.

Putting Keynesian economics next to nationalism on the evil list was so funny, I almost spit out my coffee.

Is it? Keynesian economics created the economic framework to finance World Wars.

Obligatory recommendation for: Uncommon Grounds: The History of Coffee and How it Transformed our World by Mark Pendergrast

Fantastic book. I first encountered it...in a coffee shop :) Read a chapter and immediately bought the book for myself.

At least the coffee demons aren't quite as bad as the amphetamine demons that produced Nazi Germany.

We could view as amphetamine vs. coffee / black tea.

colonizer fuel

Get a nikon j1/v1.

Honestly it seems like each major player here fumbles the ball in turn, quite fun to observe. But hey, it's a difficult game.

I have some two million KA points, and I'm currently using it to guide me around learning basic physics - I've never used Khanmigo not even once. If I need to ask AI type questions I go off site to Claude or GPT or deepseek.

As other people have noted, asking a.k.a <i>typing</i> questions, especially math-type is fatiguing, and there's no substitute for pen and paper and thinking hard.

KA would be better off using AI on the supply side (but heavily curated) to have more assignments, or better assignments in some sections.

But it's important to recognize KA for what it is, and it's an excellent way to have some sort of a basic curriculum, especially when self-studying, and all of the instructors have great teaching personalities, as far as I can deduce from the approach in the videos.

Searching HN for such a term often gets me at least some of the way there.

It's just RL-everything.