In the second part Kamen talks about how the arm's control systems were developed, simplifying an 18-degrees of freedom movement space so that it could be controlled almost subconsciously by the user.
Part three is where Kamen talks about his not-for profit scheme to get young people interested in science through robots: "For Inspiration and Recognition of Science and Technology" (FIRST); "like sports, nobody ever walks around saying 'I wanna be second'."

Interesting stuff, as I said, and the Luke arm seems to have a pretty astounding future ahead of it. I can't help thinking I'd've asked a few more direct questions though. Is the arm dexterous enough for it to let a wearer/user use the toilet? When the Luke arm gets to that level of sophistication—and, more importantly, when its developer/users trust it enough to do intimate tasks like that with it—that's the point at which I reckon the arm will stop being a science-technology showpiece and really make a difference in people's lives. Over to you in the comments. [Kara.AllthingsD]

Dean says that fatalities are down because of battlefield tech and triage methods. But that many soldiers are coming back missing limbs. He wanted to make an arm to replace their missing ones. He wants it sensitive enough to pick up a grape or allow soldiers to use a razor to shave, but be self-contained in terms of power. And a two- year deadline.

He say that a year later, they built an 8.9-pound arm using titanium, custom motors, and so on. There's 18 degrees of freedom, and they're now seeing a demo of a man who is scratching his nose. Dean says he did this in one year.

The control techniques are revolutionary. He's playing a video of a guy who didn't have both his arms for 18 years, and learned how to use the arms effectively in less than two dozen hours of training. He's showing a video that shows a guy who knows how to punch, pass a Ping Pong ball to his friend and pour a drink for another man who is holding a cup with the same type of arm. Then the video shows Chuck, the man with no arms, for the first time in 13 years, feeding himself cereal.

Holy shit, now he's showing a video of a guy using the arm using only his MIND. He learned this technique in two days, but Dean says it was more like the system learned how to interface with the human.

Looking at what he's doing, the guy drinks and people applaud. It's been two days. But the amazing thing is that he's put the cup down so it's become a lower brain stem function in two hours of doing cup functions.

Attaching the arm directly to nerves required a lot of surgery.

But there are limited arm functions, even if it's very complicated. Learning how to control a back hoe, with four controls, takes years. And the arm has 18 degrees of freedom. But people don't learn how by using each degree. In fact, it's more efficient, Dean says. There are three degrees of freedom, so they did macros. With this, a man learned how to pick up bottles, nails and other items.

Attaching the arm was a challenge, day to day. Nine pounds on an arm is heavy over a few minutes, let alone a day. So they knew that no one would wear them because of that. So Dean designed air bladders that shift the weight on the body when passive (like fidgeting in a chair) and inflate to be hard when the servos in the arm detect load.

When they did a demo for the secretary of the Army, they showed a man picking up 12 grapes and eating them without breaking or dropping any.

You can literally use infrared light, reading signals going through the skull without any invasive insertion. That's what we're working on next as a controller.

Dean is taking five minutes to explain the plight of the modern world and the responsibility of the smart, rich people in the world to help change that. I'm not sure I have the words to express his thoughts, so I'll wait for the official D video and embed it here later.

Vid from All Things D:

[All Things D]