Additively manufacturable micro-mechanical logic gates
nature.com
nature.com
Also, how many toggles can each gate go through before material fatigue causes the logic to get stuck? Some interesting questions which would need answering before it can be utilized by any industry.
I did a PhD in a materials science lab, and my understanding is that at least for metals, you still eventually run into fatigue & failure, even if you stay within the elastic regime (which nominally appears reversible). I'm not sure why plastic deformation would be any better, given that you'll have atom positions shifting and (if crystalline) dislocations propagating. I'm not a fatigue expert by any means, so I'd love to learn more.
On the Wikipedia page for fatigue limit[1], I see a link to a reference that says there are no metallic materials that can be infinitely cycled[2]. Is the bonding somehow different in this 3D printed material that causes fatigue to work differently?
[1] https://en.wikipedia.org/wiki/Fatigue_limit
[2] https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1460-2695....
An analogy might be with transistors - if you run them at high temps, you might get ten years out of them. If you're running them at room temps, you might not be able to see signs of anything other than sporadic failure even over long periods of time.
So the question to answer is, "how does a multi-million pixel display unit array of doubly supported tortional Al hinges going through >1% strain survive for 1000s of hours (much longer than the bulbs) oscillating at 100s of kHz". That's ~10^12 cycles each with ppm defect rates!
Since you know that this far exceeds any reasonable fatigue strain and the defect density /dislocation propagation should be huge! The key is that the aluminum is <1um thick a few um wide and <100um long. The majority if the strain is concentrated at the supported ends, but it's so thin that the whole high strain region is single crystal!
TI didn't originally know why it worked... just that it did.
I won't say mechanical gates are a great idea... and at 1MHz they might start failing after a few continuous months. The truly unfortunate part is that the manufacturing processes aren't really designed to control for the grain structure... they're designed for etch repeatability and conduction stability so yield could fall apart while tour processes seem nominal.
Like as if transistors can't pull that out. Just active logic families all went extinct long long time ago because passive logic (powered at idle) was so much easier to design.
We already have micro-controller designs with zero leakage current at standby(with fast wakeup), which is practically zero-leakage:
https://ieeexplore.ieee.org/document/6690972
I wonder why aren't they being commercialized though.
The Diamond Age is upon us.
I think I remember something about an idea for a mechanical communications system for a Venus lander that worked by wheels that increased or decreased radar reflections so data could be read from orbit by bouncing a radar signal off it.
Maybe combine stuff like this?
Edit: adding link: https://www.theengineer.co.uk/mechanical-rover-explore-venus... .
Sounds like this would be ideal for use in spacecraft.
In other words, it's nice to know that they were able to achieve these results on a 3D printer rather than a multimillion dollar MEMS facility.
Current 3d processes really can’t do that. Yet.
I don't think MEMS is an awesome term for mainstream usage ...
How about "mechonics"? Or "springonics"? Maybe "flexonics"? :)
Was it because the mechanical parts are too prohibitively rigid/inflexible/heavy/expensive for a computer? Or, a real barrier for mechanical computers doesn't really exist, and we didn't have it simply because it was not economically worthwhile to build one after electronic computers were feasible?
1) Energy loss due to friction & constantly working against inertia (regular and rotational).
2) I don't think you could get anywhere close to even a kilohertz without the whole contraption shaking itself apart. When we say a CPU has a clock of 1GHz, this literally means some components are being activated and deactivated a billion times a second.
Both problems seem to be correlated with size. That is, the smaller it gets, the faster a mechanism can run.
I do agree with (2) though - I think anything macroscale would simple be orders of magnitude slower than what we can archieve at microscale. I don't know if there is any way out of this.
This is what I was wondering about.
A general-purpose computer, abierto how slow, is still a computer that can process huge amount of computation. Back in the 19th century, the availability of many mathematical and engineering tables was still a problem. And in 1920s, to calculate the requirements of the Afsluitdijk dam project in the Netherlands, the famed physicist Lorentz helped deriving a model from basic fluid dynamics, and it took several years to run the "computer simulation" - to calculate the differential equations in that model numerically by a team of human computers.
Lorentz said,
> The numerical calculations were so lengthy, that we came close to the ultimate limit of what can be done in this way. I myself had no part in this. I did try once or twice to set up and work out such a calculation, but then it would turn out that I had made a mistake, so that it had to be done all over again by others.
As it has been pointed out, Analytical Engine was a real possibility and unlike the Differential Engine, it was genuinely Turing-complete (I thought it was just a numerical solver, and believed Bruce Sterling's Sci-Fi was a bit exaggeration). Just imagine how the course of history would change if some military or industrial funding in the 18th century went to build such a computer instead...
> Was it because the mechanical parts are too prohibitively rigid/inflexible/heavy/expensive for a computer?
Yes, and it was all those reasons at once. Electrical/electronical computers were better at every metric simultaneously.
> a real barrier for mechanical computers doesn't really exist, and we didn't have it simply because it was not economically worthwhile to build one after electronic computers were feasible
Bit of both: electronics is easier to miniturise, and as a result of that it's easier to manufacture, easier to maintain, lighter, and consumes less power.
Speed of operation of a mechanical computer is limited by the acceleration of the parts.
Without computer you could do it old-way with a panel of switchable bits and clock signal. You enter required bits with user-switchable levers, then switch clock lever up and down, then enter another machine-word. Or make your program on punch cards.
Ultimately the code would compile down to binary; getting it into the machine is just like any other interface.
The idea is that the CPU and peripherals would communicate via mechanical linkage (say, levers moved, or not moved, according to whether the signal is "high" or "low") rather than electronic voltage levels on a wire. For some peripherals, electromechanical adapters could be built that use relays to convert electronic signals to mechanical ones and back, allowing you to theoretically even plug in standard PC keyboards and displays into such a mechanical computer.
soln: save movie file & open using video player
Also, for anyone else having issues playing it, it's posted on YouTube: