4 ms·

- "...active control system..." https://spectrum.ieee.org/this-maglev-heart-could-keep-cardiac-patients-alive https://spectrum.ieee.org/this-maglev-heart-could

- "...active control system..." https://spectrum.ieee.org/this-maglev-heart-could-keep-cardiac-patients-alive https://spectrum.ieee.org/this-maglev-heart-could-keep-cardi... That's some high-stakes software programming! Passively-stable magnetic levitation is possible with diamagnetic materials (notably including superconductors), but those probably don't meet the requirements of this project. - "This positional control system works as follows: Tiny contactless sensors send out magnetic fields that interact with the rotor, determining its exact location many times per second. If the rotor is moving in one direction or another, the control system puts electrical energy into electromagnetic coils within several actuators, causing them to cancel out that movement."

elromulous 2y ago
Yes, but not as high-stakes as an autopilot in a commercial aircraft!
- argiopetech 2y ago
  Perhaps, but there are a pilot and first officer to take over if the autopilot goes out. You better be in the OR if your titanium heart tries to kill you...
- iancmceachern 2y ago
  Exactly. And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant. This means that all safety critical systems on an airliner need to have 3 filly redundant, independent systems and each needs to be able to function without the other two. In even class III (implantable and safety critical meaning the patient is harmed or killed if they fail) medical devices are only required to be single fault tolerant.
  - shiroiushi 2y ago
    >And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant. Not true. Proof: Boeing 737MAX MCAS system, which relies on only one sensor, and when that sensor ices up, causes the aircraft to fly into the ground, killing many hundreds of people in two separate incidents. This design was fully approved by the FAA.
    - iancmceachern 2y ago
      Yeah, that's a famous example of a failure in the process. The deal there was the MCAS system was originally designed such that it was thought to be not safety critical. It relied on another sensor that was also non safety critical in its other uses. But then over time Boeing made changes that made it safety critical, and rather than upgrade the hardware they put some footnotes in the manual and expected pilots to do things to avert disaster, but then they didnt properly train pilots to those changes to their duties. It was a comedy of errors on many levels. None of it changes my parent comment.
haswell 2y ago
This writeup is significantly better than the OP link. Should probably be the article of record. The section on constant flow vs. variable flow to simulate a heartbeat got me thinking about how weird it would feel to have no pulse, or what it’d be like to experience a moment of excitement/adrenaline without the accompanied pounding in my chest.
JumpCrisscross 2y ago
What are the consequences of a rotor "crash"?
12_throw_away 2y ago
I know these aren't intended for long-term use, and presumably not in ambulatory patients, but still, this passage gave me a tremendous amount of range anxiety: > Patients will wear a 4-kg external controller pack that contains two rechargeable batteries (providing about 5 hours of operation each), although they can also plug in directly to a power outlet. Like, the stress of finding a free outlet when I'm on 7% charge is already bad for my heart
- KolmogorovComp 2y ago
  That's heavy battery package. Is the heart much more efficient than these devices? I'd doubt so. Does anyone know if there's been research to extract energy from the blood directly?
  - fragmede 2y ago
    given that the heart manages to operate inside the body without those two external battery packs, I'd wager that it's more efficient.
    - kaba0 2y ago
      The heart has access to the resources of the body.
      - Rinzler89 2y ago
        Does the human body provide more power to the fleshy heart than two large external batteries?
  - jakobson14 2y ago
    The heart is massively more efficient. Just about everything in all of biology is massively more efficient. Take a moment to consider that your entire body runs on an energy budget of only around 100 watts, of which your brain only uses a measly 20 watts.
smusamashah 2y ago
Article doesn't explicitly say that, is there actually a software running inside this heart? That's very anxiety inducing.

elromulous 2y ago

Yes, but not as high-stakes as an autopilot in a commercial aircraft!

argiopetech 2y ago
Perhaps, but there are a pilot and first officer to take over if the autopilot goes out. You better be in the OR if your titanium heart tries to kill you...
iancmceachern 2y ago
Exactly. And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant. This means that all safety critical systems on an airliner need to have 3 filly redundant, independent systems and each needs to be able to function without the other two. In even class III (implantable and safety critical meaning the patient is harmed or killed if they fail) medical devices are only required to be single fault tolerant.
- shiroiushi 2y ago
  >And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant. Not true. Proof: Boeing 737MAX MCAS system, which relies on only one sensor, and when that sensor ices up, causes the aircraft to fly into the ground, killing many hundreds of people in two separate incidents. This design was fully approved by the FAA.
  - iancmceachern 2y ago
    Yeah, that's a famous example of a failure in the process. The deal there was the MCAS system was originally designed such that it was thought to be not safety critical. It relied on another sensor that was also non safety critical in its other uses. But then over time Boeing made changes that made it safety critical, and rather than upgrade the hardware they put some footnotes in the manual and expected pilots to do things to avert disaster, but then they didnt properly train pilots to those changes to their duties. It was a comedy of errors on many levels. None of it changes my parent comment.

haswell 2y ago

This writeup is significantly better than the OP link. Should probably be the article of record. The section on constant flow vs. variable flow to simulate a heartbeat got me thinking about how weird it would feel to have no pulse, or what it’d be like to experience a moment of excitement/adrenaline without the accompanied pounding in my chest.

JumpCrisscross 2y ago

What are the consequences of a rotor "crash"?

12_throw_away 2y ago

I know these aren't intended for long-term use, and presumably not in ambulatory patients, but still, this passage gave me a tremendous amount of range anxiety: > Patients will wear a 4-kg external controller pack that contains two rechargeable batteries (providing about 5 hours of operation each), although they can also plug in directly to a power outlet. Like, the stress of finding a free outlet when I'm on 7% charge is already bad for my heart

KolmogorovComp 2y ago
That's heavy battery package. Is the heart much more efficient than these devices? I'd doubt so. Does anyone know if there's been research to extract energy from the blood directly?
- fragmede 2y ago
  given that the heart manages to operate inside the body without those two external battery packs, I'd wager that it's more efficient.
  - kaba0 2y ago
    The heart has access to the resources of the body.
    - Rinzler89 2y ago
      Does the human body provide more power to the fleshy heart than two large external batteries?
- jakobson14 2y ago
  The heart is massively more efficient. Just about everything in all of biology is massively more efficient. Take a moment to consider that your entire body runs on an energy budget of only around 100 watts, of which your brain only uses a measly 20 watts.

smusamashah 2y ago

Article doesn't explicitly say that, is there actually a software running inside this heart? That's very anxiety inducing.