Spintronics: Build Mechanical Circuits
kickstarter.com
kickstarter.com
I would suggest to pgboswell that it may be interesting to reach out to a few local professors who teach introductory circuits at some nearby universit(y/ies) and do an in-person demo of the components. You may find you have a significant educational market you could tap into. I could well believe there's a lot of people who just never quite make it over the abstraction gap to understand circuits who would be able to follow them if they could physically interact with a mechanical circuit running at human orders of magnitude.
Highly recommended if you’ve got a kid in your life who likes figuring out and building things. https://www.turingtumble.com/
I tried it with my kids and they were very excited up until this unreliability killed all the fun. I wish Turing Tumble had a premium version with a better determinism.
Hopefully, Spintronics would be more reliable, given that the author is well aware of the unreliability issue with Turing Tumble.
My impression is that the main design flaw with Turing Tumble is the steep board angle, and it would have worked a bit better if designed for a 45° (or something) board. That and using heavier rotating parts with a bit higher moment of inertia. But I think it’s still great despite the occasional malfunctioning part.
As for frustrated kids: I think interaction with an adult who could notice parts sometimes malfunctioning (and correct them on the spot) would probably help forestall some frustration. But my kid is only 4.5 so we have to do the puzzles together.
Probably, an update to a later version. I don't know?
Specific thread that I had read at the time is https://community.turingtumble.com/t/crossovers-dont-work-or...
While my memory is fuzzy, it was indeed crossovers which caused majority of undeterminism, at least in the set I had. There are some alternative 3d-printable implementations if you walk by the links there. I didn't try.
If/when technology switches over to the micro-mechanical, we'll suddenly all be scrambling to re-introduce a generation to this 1800s-era mechanical design stuff...
Probably not. Micromechanics is completely different from larger scale mechanics, the kinds of problems you have to solve and the tools you have to solve them are often completely turned on their head.
For now, it looks like the progress has mostly been:
mechanical -> electrical -> optical (/RF)
Basic principles haven't changed much though, and it's always interesting to understand those. There is just the "field" concept that can be tough to understand.
I can't think of anyone I know close to me that would really appreciate this gift, so I'm with another comment on here that gifting it online somehow would be something I'm interested in. I'd feel happy knowing I'm supporting a great product and helping the less fortunate of the younger generation get better access to fun educational tools.
Also, I wish there were a pledge level where I'd buy one kit for me, and anonymously gift one to any random kid in another part of the world who wants one but can't afford it (kind of like OLPC did).
That's a great idea with the anonymous donation. If anyone is looking for a great place to donate, one really cool program is the Turing Trust. It's run by Alan Turing's great nephew, James Turing. He's awesome and he does amazing work. Here's their website: https://turingtrust.co.uk/
Most of the popular electronics books I've seen use a water or fluid metaphor to describe how components work (eg the fantastic Practical Electronics for Inventors).
Not at all intending to be critical with my question, just curious.
As a non-electrical engineer who dabbles in electronics, I'm excited for your work to help others learn and happy I can back it!
So I stepped back and thought about how to do it mechanically. But the hardest part of a mechanical circuit is the absolute simplest part in electronics: the junction. That is, where electricity flows in one wire and splits along two wires. How do you make chain or a belt split? Not only that, but it has to follow Kirchoff's law: the sum of currents leaving the junction must equal the current entering the junction. I finally realized that's what a differential gear arrangement does, and planetary gears are a sort of differential arrangement that would work perfectly for this. It was very, very hard to make the mechanical junction so that it had low resistance while under load, but I eventually got it. Once I had that, I knew it would all work.
BTW We got Turing Tumble for my son and he really enjoyed it.
My first guess was that the analogy here appears to be velocity is voltage and force is current, but I think I have that backwards. The battery, which I was taking to be a ideally a voltage source without internal resistance, appears to be a constant-torque mechanical device. Connecting it in series to different resistances means it spins at different speeds (different current is drawn).
But the battery will also spin if it's not connected to anything... so I'm struggling to keep the analogy straight while thinking about how these parts behave ideally and non-ideally.
Looking at the ammeter, it's definitely velocity = current.
Edit: and finally direct evidence
> But the most practical place for [ground] to be is anywhere there is zero force (i.e., voltage) on the chain.
Edit: I suppose a/the major reason is to get the resistance = friction analogy down. With current as torque, friction acts as conductance. E.g., a constant-torque/"current" motor would need to be held still (high friction) to prevent its speed/"voltage" from growing, whereas with the equivalent electrical circuit, you need to short the terminals (low resistance) of a current source to do the same.
I suppose the reason for this seeming discrepancy is that, in an electric circuit, wires are separated by high resistance. But in a physical circuit, "wires" are separated by low friction (= not touching). Flipping around the natural behavior of a junction allows you to take the dual of the entire circuit, thus causing the behavior of resistance and friction to line up.
This isn't so much analogies, more that the physics of natural systems means they're governed by 2nd order differential equations, so really do behave the same.
More importantly, they're all forms of energy and transferable. Power=IV=Fv=TO=PQ.
The analogizing comes from saying "I is like P and V is like Q", or vice versa.
2nd order ODEs are very common, and I agree that it is unifying to see different systems modeled by the same equation. But I think more fundamental than that is the understanding of "through" and "across" variables, the notion of a "port" [1], and series/parallel toplogies for combining two one-port components to form a new one-port component.
You could still make an analogy between domains, even if you don't have second-order ODEs. This is clear even from your comment because, note that a spring+damper is going to be a first-order ODE. You would need moving mass to store kinetic energy, in addition to the spring to store potential energy.
Spin Volt = 0.1 newtons
Spin Coulomb = 10 meters of chain
Spin Ampere = 10 meters of chain per second
Spin Ohm = 0.1 newton-seconds per meter
Spin Farad = 100 meters per newton
Spin Henry = 0.01 newton-second-seconds per meter
Spin Watt = 1 newton-meter per second
For at least planar circuits there is a dual circuit that is equivalent with voltages and currents switched. So maybe both analogies are correct.
https://basicelectronicsguide.blogspot.com/2018/08/duality.h...
This is what I wish I'd had at the time. I'd have understood intuitively what each of the components did. The time-scale is slowed down enough that I could see what was going on. I could build and test in stages and see how each new change affects the outcome. Endless experimentation and possibilities...
This is just terrific!
Is a pleasurable learning experience.
NB:This post and OpenFlexure
After years of working with electrical circuits, I now often find it easier to translate a mechanical system in question to an analogous electrical system and analyze it. In fact this is where the phrase "analog electronics" comes from: It is an analogue of a real world (often mechanical) system. At the end of the day, these are all (mostly second order) differential equations.
They will take a long time to compute something like SHA2
TL;DR we're nowhere close to exploiting the full potential of nanoscale mechanical systems.
Since I just now learned about that link, I haven't read the book to know, but I have always been interested in finding out if the ability to create smaller and smaller machines is possible by having an outer machine which manufactures an inner, smaller, copy of itself, apply the process of induction, define the termination criteria, ..., profit!
Or, maybe I'm thinking about the problem all wrong -- it's not the actual construction machinery that's the problem, it's providing the input materials to each step (gears, levers, fasteners, wiring(?), etc)
There's a Factorio-clone hiding in this problem ...
So you end up having to learn an experiment at a more and more difficult to access scale to figure out how to make something actually work.
That’s real life anyway.
Many cell phones now have sensors that are mems-based, built using lithography (accelerometers being the best example). In many senses, we've started to achieve the goals of the book.
You might also enjoy Diamond Age.
I'm about 175 pages into that PDF and am now sorry that I drew attention to it. I was beguiled by the name recognition and the snazzy title, but I find the text filled with hand-wavery and aspirational thinking, and it also seems to focus a lot more on DNA than I would have expected
I also find even their aspirations suspicious that any such machinery could ever possibly exist to just tweezer atoms around like marbles and voila gold from lead!
We can already push atoms around with macro-scale actuators that have nano-scale accuracy (which is clumsy, to be sure), and there is little doubt that the hardware to do so will get smaller and more capable over time.
This is because the speed of sound, which limits how fast mechanical signals can propagate, is much lower than the speed of light.
The main advantages of rod logic is that its compact and power efficient. The aforementioned CPU would consume ~100 nW.
Really the reason why Drexler analyzed rod logic in the first place is that it was easy to analyze and something that his proposed assemblers could plausibly construct, better alternatives for fast computing may exist.
You're implying that parallelization can make up for the slower clock speeds, which is true but only for some workloads, and then the system is constrained by bandwidth to get instructions and data to the parallel cores as fast as possible.
I've marked your account legit so this will not happen to you again, and I've approved your comments that got throttled, so they're up now. Welcome to HN and congratulations on this exceedingly cool work.
Reversible computing tries not to destroy information, allowing to go under Laundauer's limit [1].
When you discard the previous value held by your flip-flop, you clear the output bit, returning electrons (or a chain displacement) to the power supply. If you can instead repurpose that energy, you'll have to supply a lot less energy since you'll dissipate less. That would be reversible or adiabatic computing [2]. I have to note that processors these days are mostly power-limited, trying not to melt themselves as the energy flux inside a chip approaches that of a nuclear reactor. Just look at modern sockets and count the pins dedicated to power supply![3]
[1]: https://en.wikipedia.org/wiki/Landauer's_principle
[2]: https://en.wikipedia.org/wiki/Reversible_computing#Reversibi...
[3]: https://arstechnica.com/gadgets/2015/11/5d-electronic-blood-...
Of course electronics aren't standing still, but resistance tends to get harder to deal with as feature sizes decrease.
See more generally: https://en.wikipedia.org/wiki/Nomogram
This was an important component in mechanical computers to amplify outputs disc integrators which outputted shaft rotations at low torque.
It might be a fun device to make because you could use this to make part of a steampunk exoskeleton where the user can turn a small arm to move a much large arm. Because torque is amplified it will be easier to move the heavier arm.
That said, I wonder if it will really make learning circuit easier. I have a hard time imagining that kids would give up learning circuit just because they couldn't get the abstractions. The biggest obstacle to learning, per my limited observation of course, is always lack of innate curiosity or sometimes talent. Those who get discouraged by the so-called difficult abstraction probably do not need to learn circuitry in the first place.
By the way, I find the promotional video interesting. There are a few frames that talk about how a kid had to resort to maths and what not to understand circuits, and videos showed kids checking out oscilloscopes, square waves, some complex circuits that looked like Y-delta transforms, and voltage-ampere curves (or something like that). I mean, if a kid would look into those things, why would we worry that the kid can't learn circuit? And since when looking into math is a bad thing?
Boswell's idea seems aligned with the movement of progressive math education in the US, which advocates that there's gotta be an easy and intuitive way to motivate and enable every kid to discover and grasp math concepts. I think it's a noble goal. I'm just not sure if everyone is born with the drive or aptitude.
When you hear people avoiding math in teaching, they usually mean avoiding the rote "non beautiful" perversion of math frequently presented by educators with limited math experience.
This really helps visualize how one might make "computation" with mechanical parts possible!
When I was taking physics, the water analogy of circuitry helped me out a lot, especially with regards to capacitors and inductors. Inductors being like a water wheel, taking time to ramp up to speed then reinforcing flow of current (as I remember?). And capacitors being like a rubber sheet separating water. A strong current provokes a respective force against the water on the other side and slowly stretches the rubber until current stops; the key thing is it requires constant voltage to keep the rubber stretched; the elastic energy of the rubber is analogous to the stored electric field in a capacitor (?).
Physics was hardest for me... I preferred the more structural and compositional nature of computer science. Things changing continuously is hard for my brain :(
My question is can you simulate how resistors behave in series versus parallel? How about capacitors?
I pick third grade only because I was thinking about kids safety. I don't know when kids stop swallows stuff these days.
I wonder why they don't start teaching kids important stuff early on, like; mechanics, finance, starting a business (profitable lemonade stand, and how ridiculous a permit is technically needed to operate, building residences. I for one colored to many maps, and memorized who Ecuador produces.
I think in the USA electronics couldn't be taught in grade school is the shortage of teachers who barely understand electricity, and math now, but that would change eventually?
I just pictured a dad from the future telling 13 year old Opie to fix the Tesla in Dan Akroyd voice. "Opie, but you learned how to properly dischge a capacitor in Miss Orliey's class?"
Maybe just reading, writing, and arithmetic after all that?
These are used, for example, in avia and rocket engines - in first or independent contours of their control systems. Such logic devices are very reliable, relatively simple and can work at extreme temperatures.
Electrons have spin. Although 'classical semiconductors' exploit the electron's spin via the Fermi-Dirac distribution in transistors, the actual sign / direction of the 'spin' is ignored in everyday electronics. Making use of this available spin degree-of-freedom opens up a whole wealth of new possibilities.
Spintronics has already revolutionized certain industries (eg, GMR in magnetic hard drives), and there are further open areas of research (eg, spin as qubit basis states in quantum computers).
(I kid of course. Spin in physics relates to inherent angular momentum. If you wonder why that exists, you may also want to wonder why mass exists.)
Addition of quantum angular momentum is really weird.