13 ms·

Spintronics: Build Mechanical Circuits

503 points by mcp_ 5y ago

pgboswell 5y ago
Hey cool! I made this. It's fun to see it here on Hacker News!
- jkingsman 5y ago
  I took four years of engineering in university and work in software now, and one gif on your page made inductors click intuitively for me in a way that so many courses did not -- thank you!
  - pgboswell 5y ago
    Ha ha! Thanks so much!
    - GistNoesis 5y ago
      I'm eager to see what a memristor would look like.
  - elliekelly 5y ago
    Is there a word or a phrase for this learning phenomenon? When someone is suddenly able to fully understand a concept that has been explained to them before but, for whatever reason, they just didn’t quite “get” it?
    - anjel 5y ago
      Epiphany
  - jbotz 5y ago
    You have a link to that gif?
  - aj7 5y ago
    In my fifties, I finally figured out that the INTEGRAL constuitive relations for inductors and capacitors were much more fundamental than the differential ones. Solved virtually all understanding problems for me.
- mcp_ 5y ago
  I loved playing your last project Turing Tumble with my daughter. So I am really looking forward to your new project.
  - pgboswell 5y ago
    Thanks so much for the kind words.
- Judgmentality 5y ago
  I'm only just hearing about this now but I love the idea and wish you great success.
- deleted 5y ago
  [deleted]
- rkagerer 5y ago
  Quick question: I noticed a Form 3 in the video. How much of the prototyping did you do on it? 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).
  - pgboswell 5y ago
    You know, I don't recommend a Form 3 except in unusual circumstances. It's labor intensive, messy, and expensive. The resin itself is expensive, but then you also have to buy expensive new resin trays frequently because they wear out fast. I used it a lot when I was finalizing the 3D models to get them ready to send off to get injection molds started. The precision of a resin printer was critical. If I were you, I'd use a service like i.materialise.com instead. The prices are low for resin prints and they're pretty fast to ship, too. 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/ https://turingtrust.co.uk/
- devgoldm 5y ago
  Really amazing work, well done! Having something like this when growing up would've made electronics so much more accessible. 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.
- garrettgarcia 5y ago
  I just pledged! My 67 year old mother got me Turing Tumble for Christmas and we worked through the first half of the puzzle book together. It was so nice to be able to explain to her what I do for a living with actual physical switches and marbles. I recommend it to everyone and anyone who will listen.
- cmason 5y ago
  I'm wondering if you'd be willing to expand on why you chose this mechanical, spinning metaphor for electronics vs some other metaphor? 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!
  - pgboswell 5y ago
    Yeah, good question. My first attempts were with fluids: water and air. Water doesn't work very well because there's a lot of resistance to flow unless the pipes are large in diameter. It's not practical for anything but the simplest of circuits. So I went with air for a long time before I realized it had no chance, either - when it compresses and decompresses, it heats and cools, and that energy is lost to the surroundings. It makes horribly inefficient circuits. It's also hard to seal moving parts without adding an unacceptable amount of friction. And finally, you still can't see air moving through a circuit. 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.
  - caspar 5y ago
    This is actually explained on the Kickstarter ("The Making of Spintronics" section).
- hermitcrab 5y ago
  Seems a great idea. I did a physics degree and never 'got' electronics (Voltage, Capacitance etc) at an intuitive level in the same way that I did mechanics (Force, Mass etc). BTW We got Turing Tumble for my son and he really enjoyed it.
nemo1618 5y ago
I've always been curious how far we could push "mechanical computation." Seems like even an operation as simple as multiplication requires tons of metal. If I wanted to compute, say, a SHA2 hash or an Ed25519 signature with zero electricity, would I need a room-sized machine?
- pgboswell 5y ago
  For sure - at least with the parts in their current form. A simple flip-flop takes up a minimum space of about 30 cm x 30 cm. But I wonder how small these parts could get. Like, what if spintronics was invented in the 19th century instead of the 21st century? Would Moore's law have applied to mechanical transistors?
  - dekhn 5y ago
    See https://en.wikipedia.org/wiki/There%27s_Plenty_of_Room_at_the_Bottom https://en.wikipedia.org/wiki/There%27s_Plenty_of_Room_at_th... and https://en.wikipedia.org/wiki/Engines_of_Creation https://en.wikipedia.org/wiki/Engines_of_Creation TL;DR we're nowhere close to exploiting the full potential of nanoscale mechanical systems.
    - mdaniel 5y ago
      For those who don't click on the Engines of Creation link, be aware that at the bottom of that page is a PDF link to the gratis version of Engines of Creation 2.0 from 2007: https://web.archive.org/web/20140810022659/http://www1.appstate.edu/dept/physics/nanotech/EnginesofCreation2_8803267.pdf https://web.archive.org/web/20140810022659/http://www1.appst... 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 ...
sumthinprofound 5y ago
Wish I had this as a kid but still excited to own it once it's released!
dpeck 5y ago
This is from the same person (team?) that made Turing Tumble, which has been great fun to do with my 8 year old. The puzzles are a lot of fun and gives a nice intuitive feel for “circuits” and basic mechanical logic ( ands, ors, counters, etc) computation. Highly recommended if you’ve got a kid in your life who likes figuring out and building things. https://www.turingtumble.com/ https://www.turingtumble.com/
- krasin 5y ago
  Yes, this is from the same person. Turing Tumble is almost amazing. Unfortunately, gears and balls used there are not reliable enough and more complex circuits have abysmal reproducibility (~50%). 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.
  - coupdejarnac 5y ago
    Sounds like a pretty authentic engineering experience then.
    - krasin 5y ago
      Yes. But kids like to be exposed to the joy of engineering first. It's otherwise hard for them to justify the pain that's required to get to the joy of success.
      - jacobolus 5y ago
        Did you try putting the little “high-friction washers” on the gear pieces?
        krasin 5y ago
        Sadly, by the time I discovered the community improvements / hacks, my kids lost all the interest. Hopefully, Spintronics would be more reliable, given that the author is well aware of the unreliability issue with Turing Tumble.
prpl 5y ago
Sort of unfortunate to reuse this term which has been a field of study in solid state physics for a very long time: https://en.m.wikipedia.org/wiki/Spintronics https://en.m.wikipedia.org/wiki/Spintronics
- lapetitejort 5y ago
  The main difference is that spinning gears makes sense, whereas spinning electrons do not! (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.)
  - whatshisface 5y ago
    Intrinsic angular momentum is weirder than intrinsic mass because you can take it out and put it back in - although for most particles you're not allowed to have zero. But you are allowed to take 1 from an electron to go from 1/2 to -1/2. If that is not enough, you can go back from -1/2 to 1/2 by changing your basis vectors. ;)
    - jeffwass 5y ago
      Further - paired electrons can collectively form the spin-zero singlet state, or spin-one triplet state. In either case the two electrons, which are fermions independently, together act like a boson (eg, Cooper Pairs in a Superconductor). Addition of quantum angular momentum is really weird.
    - jacobolus 5y ago
      I don’t know enough physics and haven’t put in enough effort to understand https://arxiv.org/pdf/1910.10478.pdf https://arxiv.org/pdf/1910.10478.pdf but it seems intriguing.
      - whatshisface 5y ago
        I thought complex phase precession was from energy, I don't see how it's related to spin.
lapetitejort 5y ago
I'm amazed at all the ways we can simulate circuits. The classic is pipes and water, however you can also use car traffic, heat transfer, and now gears! My question is can you simulate how resistors behave in series versus parallel? How about capacitors?
- deleted 5y ago
  [deleted]
- pgboswell 5y ago
  Yup. I actually tried making an analog of electronics with water and air first. Water didn't work very well because of the high resistance. Air didn't work very well because of it's compressibility - each time it compresses and decompresses, there's serious hysteresis and you lose a ton of energy.The trickiest part to make in a mechanical version is the simplest part in electronics - the junction: Where one wire splits into two wires. I spent a lot of time trying to figure out how to do that with anything besides a fluid or a gas. Fortunately, planetary gear systems do the trick. Once I got that working, everything fell into place. Using a junction, you can easily make parallel circuits. Capacitors are just torsion springs in the spintronics model.
Xunxi 5y ago
I personally find it quite refreshing to see accessible hardware projects showing up once again. The ensuing discussions are full of nuggets and somewhat esoteric recommendations that always draws me down the rabbit hole where I end up discovering a lot of things I wish I could visualize when I was much younger. Is a pleasurable learning experience. NB:This post and OpenFlexure
ocdtrekkie 5y ago
This reminds me of something I read about the other day (probably also from HN), a mechanical exploratory rover: https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus This really helps visualize how one might make "computation" with mechanical parts possible!
lxe 5y ago
Mechanical inductors, capacitors, and even transistors? That's and incredible feat. Developing intuition about how to put the components together to build something like an oscillator or a flip flop is a must for electronics enthusiasts.
quanto 5y ago
This reminds me of when I was taking an advanced circuit design class. The analog circuit in question had many moving parts, and I just didn't have the intuition. The teaching fellow at the time thought it would help to visualize a mechanical analog (ha!) of the circuit and drew for me a complex mechanical diagram. It was so complex that I found it more intuitive to just study the electrical circuit directly. 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.
syoc 5y ago
This looks really cool. Would be interested myself even if I am probably outside the intended age bracket. I can't help think that the parts look really flimsy based on the videos. They look kind of 3d printed and the plastic seems cheap. Hope that's not the case.
- adeledeweylopez 5y ago
  That's probably because they are 3D printed prototypes. He says in the link that they're working on creating the molds for injection molding.
gene-h 5y ago
I wonder if you could make a torque amplifier[0] with the transistors? A torque amplifier is a mechanical device which takes in a shaft rotation and power outputting the same rotation angle except with higher torque. 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. [0]https://en.wikipedia.org/wiki/Torque_amplifier https://en.wikipedia.org/wiki/Torque_amplifier
- Doxin 5y ago
  I'd imagine that would have to be possible, seeing as the junctions function as differentials. It might be as simple as adding negative feedback to the input of the transistor, though we'll probably need to wait for spintronics to be shipped to find out for sure.
- mcphage 5y ago
  That seems to be where physical computing (pulleys, etc) always falls down—no amplifier. So the system needs to be input with more and more energy, the more gates there are.
jerf 5y ago
I am positively agog. This is amazing. 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.
gugagore 5y ago
I am glad to see that they are using LEGO Technic chains (https://www.bricklink.com/v2/catalog/catalogitem.page?P=3711 https://www.bricklink.com/v2/catalog/catalogitem.page?P=3711) , and therefore the gear pitches are LEGO compatible (at least with the non-bevel gears, but the traditional spur gears). I am excited about the potential of interacting with existing Technic parts!
- scott-smith_us 5y ago
  Ah. I wondered about their choice of chain type vs a ball/bead chain. Now it makes sense.
- worldsayshi 5y ago
  Wow, that's a nice feature!
gugagore 5y ago
There are two possible mechanical analogies to electrical circuits (https://en.wikipedia.org/wiki/Mechanical%E2%80%93electrical_analogies https://en.wikipedia.org/wiki/Mechanical%E2%80%93electrical_...). In domains (electrical, acoustic, thermal, mechanical, ...) there are two kinds of quantities, sometimes called "across" (voltage, temperature difference, ...) and "through" (current, heat, ...). 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.
- colanderman 5y ago
  Interesting, I'm curious why this analogy was chosen, and not the other way around. Current as torque and voltage as (rotational) velocity would seem to allow the junctions to be much simpler -- just a gang of gears on a single axle, rather than the differential mechanism used here -- since torques (like current) add at an axle/junction, while rotational velocity (like voltage) transmits through an axle/junction. 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.
  - mdiesel 5y ago
Animats 5y ago
Oh, that's precious. I hope they ship this, and that the components aren't too expensive. They look expensive.
ajarmst 5y ago
I was a backer for their previous project: Turing Tumble. It was a very positive experience, with timely informative updates and ultimately a high quality product.
- spoonjim 5y ago
  Turing Tumble is so great.
spoonjim 5y ago
I was going to say “this better be as good as Turing Tumble!” Now I see it’s by the same guy. BUY
deleted 5y ago
[deleted]
d--b 5y ago
This is great! I didnt even know there were mechanical analogs to electronic parts. This is going to make electronic teaching an awful lot mote intuitive!
- c-smile 5y ago
  There are also such things as "pneumonics" and "fluidics" : https://en.wikipedia.org/wiki/Fluidics https://en.wikipedia.org/wiki/Fluidics 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.
- hellbannedguy 5y ago
  The USA should start teaching electronics in third grade, and through high school. Don't even grade the kids. I think it's more important ever for kids to know. 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?
hintymad 5y ago
This is amazing and looks fun! I immediately paid to support the project, so I can play the toy later. 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.
- krastanov 5y ago
  I teach and from my experience drive and aptitude is not the problem. "Math" and "abstraction" are not the problem either, except that for many educators they are synonymous with rote memorization which leads to ridiculous amounts of math phobia in the US that I have not seen in Europe. 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.
spoonjim 5y ago
To the founder’s point about math not being necessary for developing intuition about electronics: Michael Faraday’s three volume treatise on electromagnetism, which essentially created the entire scientific field, has essentially zero math in it.
pontusrehula 5y ago
The heading seemed contradictory to me with both "spintronics" and "mechanical" in it until I realised that it is not the other sprintronics (https://en.wikipedia.org/wiki/Spintronics https://en.wikipedia.org/wiki/Spintronics).
- Pet_Ant 5y ago
  Yes I and pedantically bothered by the fact that it isn't really about spintronics nor electronics, but rather mechanical engineering and merely co-opting a more marketable term... that said I'll still buy a copy for my kids. Already playing LaserMaze with them. Even if they don't end up in stem I hope it helps in their A levels one day. https://www.thinkfun.com/products/laser-maze/ https://www.thinkfun.com/products/laser-maze/
ofou 5y ago
Where is the memristor?
oceanghost 5y ago
Amazing. I have a friend whose building a logic system for marble runs-- think and/or/xor/nor gates made with marbles. I love stuff like this.
- ZeikJT 5y ago
  Might want to point them at Turing Tumble, another project by the same creators. https://www.turingtumble.com/ https://www.turingtumble.com/
scott-smith_us 5y ago
In high school I took electronics and learned enough about capacitors, inductors and transistors to design and test simple circuits. I'd gotten a Radio Shack "100-in-1" kit when I was in fifth grade, but the projects within were all opaque recipes to me. Most circuits had illustrations with cartoons components saying things like "I'm the capacitor, and I give a little 'kick' to the transistor!". I remember being kind of surprised at just how un-enlightening these cartoons were. If I followed the wiring steps for a project and then it didn't work, I'd double-check my wiring. If it still didn't work, there was nothing further to do; I just gave up. I had no idea how it 'ought' to work, so there was nothing I could measure or verify that would mean anything to me. 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!
- amelius 5y ago
  Another approach would be to have capacitors with little leds on them which show charge, leads with little leds which show current, etc.
kizer 5y ago
You'd think the water analogy would be easier to build and sell. Regardless, the more "analogies" the better, as the abstract concept reveals itself more readily. 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 :(

503 points by mcp_ 5y ago

pgboswell 5y ago

Hey cool! I made this. It's fun to see it here on Hacker News!

jkingsman 5y ago
I took four years of engineering in university and work in software now, and one gif on your page made inductors click intuitively for me in a way that so many courses did not -- thank you!
- pgboswell 5y ago
  Ha ha! Thanks so much!
  - GistNoesis 5y ago
    I'm eager to see what a memristor would look like.
- elliekelly 5y ago
  Is there a word or a phrase for this learning phenomenon? When someone is suddenly able to fully understand a concept that has been explained to them before but, for whatever reason, they just didn’t quite “get” it?
  - anjel 5y ago
    Epiphany
- jbotz 5y ago
  You have a link to that gif?
- aj7 5y ago
  In my fifties, I finally figured out that the INTEGRAL constuitive relations for inductors and capacitors were much more fundamental than the differential ones. Solved virtually all understanding problems for me.
mcp_ 5y ago
I loved playing your last project Turing Tumble with my daughter. So I am really looking forward to your new project.
- pgboswell 5y ago
  Thanks so much for the kind words.
Judgmentality 5y ago
I'm only just hearing about this now but I love the idea and wish you great success.
deleted 5y ago
[deleted]
rkagerer 5y ago
Quick question: I noticed a Form 3 in the video. How much of the prototyping did you do on it? 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).
- pgboswell 5y ago
  You know, I don't recommend a Form 3 except in unusual circumstances. It's labor intensive, messy, and expensive. The resin itself is expensive, but then you also have to buy expensive new resin trays frequently because they wear out fast. I used it a lot when I was finalizing the 3D models to get them ready to send off to get injection molds started. The precision of a resin printer was critical. If I were you, I'd use a service like i.materialise.com instead. The prices are low for resin prints and they're pretty fast to ship, too. 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/ https://turingtrust.co.uk/
devgoldm 5y ago
Really amazing work, well done! Having something like this when growing up would've made electronics so much more accessible. 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.
garrettgarcia 5y ago
I just pledged! My 67 year old mother got me Turing Tumble for Christmas and we worked through the first half of the puzzle book together. It was so nice to be able to explain to her what I do for a living with actual physical switches and marbles. I recommend it to everyone and anyone who will listen.
cmason 5y ago
I'm wondering if you'd be willing to expand on why you chose this mechanical, spinning metaphor for electronics vs some other metaphor? 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!
- pgboswell 5y ago
  Yeah, good question. My first attempts were with fluids: water and air. Water doesn't work very well because there's a lot of resistance to flow unless the pipes are large in diameter. It's not practical for anything but the simplest of circuits. So I went with air for a long time before I realized it had no chance, either - when it compresses and decompresses, it heats and cools, and that energy is lost to the surroundings. It makes horribly inefficient circuits. It's also hard to seal moving parts without adding an unacceptable amount of friction. And finally, you still can't see air moving through a circuit. 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.
- caspar 5y ago
  This is actually explained on the Kickstarter ("The Making of Spintronics" section).
hermitcrab 5y ago
Seems a great idea. I did a physics degree and never 'got' electronics (Voltage, Capacitance etc) at an intuitive level in the same way that I did mechanics (Force, Mass etc). BTW We got Turing Tumble for my son and he really enjoyed it.

nemo1618 5y ago

I've always been curious how far we could push "mechanical computation." Seems like even an operation as simple as multiplication requires tons of metal. If I wanted to compute, say, a SHA2 hash or an Ed25519 signature with zero electricity, would I need a room-sized machine?

pgboswell 5y ago
For sure - at least with the parts in their current form. A simple flip-flop takes up a minimum space of about 30 cm x 30 cm. But I wonder how small these parts could get. Like, what if spintronics was invented in the 19th century instead of the 21st century? Would Moore's law have applied to mechanical transistors?
- dekhn 5y ago
  See https://en.wikipedia.org/wiki/There%27s_Plenty_of_Room_at_the_Bottom https://en.wikipedia.org/wiki/There%27s_Plenty_of_Room_at_th... and https://en.wikipedia.org/wiki/Engines_of_Creation https://en.wikipedia.org/wiki/Engines_of_Creation TL;DR we're nowhere close to exploiting the full potential of nanoscale mechanical systems.
  - mdaniel 5y ago
    For those who don't click on the Engines of Creation link, be aware that at the bottom of that page is a PDF link to the gratis version of Engines of Creation 2.0 from 2007: https://web.archive.org/web/20140810022659/http://www1.appstate.edu/dept/physics/nanotech/EnginesofCreation2_8803267.pdf https://web.archive.org/web/20140810022659/http://www1.appst... 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 ...

sumthinprofound 5y ago

Wish I had this as a kid but still excited to own it once it's released!

dpeck 5y ago

This is from the same person (team?) that made Turing Tumble, which has been great fun to do with my 8 year old. The puzzles are a lot of fun and gives a nice intuitive feel for “circuits” and basic mechanical logic ( ands, ors, counters, etc) computation. Highly recommended if you’ve got a kid in your life who likes figuring out and building things. https://www.turingtumble.com/ https://www.turingtumble.com/

krasin 5y ago
Yes, this is from the same person. Turing Tumble is almost amazing. Unfortunately, gears and balls used there are not reliable enough and more complex circuits have abysmal reproducibility (~50%). 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.
- coupdejarnac 5y ago
  Sounds like a pretty authentic engineering experience then.
  - krasin 5y ago
    Yes. But kids like to be exposed to the joy of engineering first. It's otherwise hard for them to justify the pain that's required to get to the joy of success.
    - jacobolus 5y ago
      Did you try putting the little “high-friction washers” on the gear pieces?
      - krasin 5y ago
        Sadly, by the time I discovered the community improvements / hacks, my kids lost all the interest. Hopefully, Spintronics would be more reliable, given that the author is well aware of the unreliability issue with Turing Tumble.

prpl 5y ago

Sort of unfortunate to reuse this term which has been a field of study in solid state physics for a very long time: https://en.m.wikipedia.org/wiki/Spintronics https://en.m.wikipedia.org/wiki/Spintronics

lapetitejort 5y ago
The main difference is that spinning gears makes sense, whereas spinning electrons do not! (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.)
- whatshisface 5y ago
  Intrinsic angular momentum is weirder than intrinsic mass because you can take it out and put it back in - although for most particles you're not allowed to have zero. But you are allowed to take 1 from an electron to go from 1/2 to -1/2. If that is not enough, you can go back from -1/2 to 1/2 by changing your basis vectors. ;)
  - jeffwass 5y ago
    Further - paired electrons can collectively form the spin-zero singlet state, or spin-one triplet state. In either case the two electrons, which are fermions independently, together act like a boson (eg, Cooper Pairs in a Superconductor). Addition of quantum angular momentum is really weird.
  - jacobolus 5y ago
    I don’t know enough physics and haven’t put in enough effort to understand https://arxiv.org/pdf/1910.10478.pdf https://arxiv.org/pdf/1910.10478.pdf but it seems intriguing.
    - whatshisface 5y ago
      I thought complex phase precession was from energy, I don't see how it's related to spin.

lapetitejort 5y ago

I'm amazed at all the ways we can simulate circuits. The classic is pipes and water, however you can also use car traffic, heat transfer, and now gears! My question is can you simulate how resistors behave in series versus parallel? How about capacitors?

deleted 5y ago
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pgboswell 5y ago
Yup. I actually tried making an analog of electronics with water and air first. Water didn't work very well because of the high resistance. Air didn't work very well because of it's compressibility - each time it compresses and decompresses, there's serious hysteresis and you lose a ton of energy.The trickiest part to make in a mechanical version is the simplest part in electronics - the junction: Where one wire splits into two wires. I spent a lot of time trying to figure out how to do that with anything besides a fluid or a gas. Fortunately, planetary gear systems do the trick. Once I got that working, everything fell into place. Using a junction, you can easily make parallel circuits. Capacitors are just torsion springs in the spintronics model.

Xunxi 5y ago

I personally find it quite refreshing to see accessible hardware projects showing up once again. The ensuing discussions are full of nuggets and somewhat esoteric recommendations that always draws me down the rabbit hole where I end up discovering a lot of things I wish I could visualize when I was much younger. Is a pleasurable learning experience. NB:This post and OpenFlexure

ocdtrekkie 5y ago

This reminds me of something I read about the other day (probably also from HN), a mechanical exploratory rover: https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus https://www.jpl.nasa.gov/news/a-clockwork-rover-for-venus This really helps visualize how one might make "computation" with mechanical parts possible!

lxe 5y ago

Mechanical inductors, capacitors, and even transistors? That's and incredible feat. Developing intuition about how to put the components together to build something like an oscillator or a flip flop is a must for electronics enthusiasts.

quanto 5y ago

This reminds me of when I was taking an advanced circuit design class. The analog circuit in question had many moving parts, and I just didn't have the intuition. The teaching fellow at the time thought it would help to visualize a mechanical analog (ha!) of the circuit and drew for me a complex mechanical diagram. It was so complex that I found it more intuitive to just study the electrical circuit directly. 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.

syoc 5y ago

This looks really cool. Would be interested myself even if I am probably outside the intended age bracket. I can't help think that the parts look really flimsy based on the videos. They look kind of 3d printed and the plastic seems cheap. Hope that's not the case.

adeledeweylopez 5y ago
That's probably because they are 3D printed prototypes. He says in the link that they're working on creating the molds for injection molding.

gene-h 5y ago

I wonder if you could make a torque amplifier[0] with the transistors? A torque amplifier is a mechanical device which takes in a shaft rotation and power outputting the same rotation angle except with higher torque. 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. [0]https://en.wikipedia.org/wiki/Torque_amplifier https://en.wikipedia.org/wiki/Torque_amplifier

Doxin 5y ago
I'd imagine that would have to be possible, seeing as the junctions function as differentials. It might be as simple as adding negative feedback to the input of the transistor, though we'll probably need to wait for spintronics to be shipped to find out for sure.
mcphage 5y ago
That seems to be where physical computing (pulleys, etc) always falls down—no amplifier. So the system needs to be input with more and more energy, the more gates there are.

jerf 5y ago

I am positively agog. This is amazing. 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.

gugagore 5y ago

I am glad to see that they are using LEGO Technic chains (https://www.bricklink.com/v2/catalog/catalogitem.page?P=3711 https://www.bricklink.com/v2/catalog/catalogitem.page?P=3711) , and therefore the gear pitches are LEGO compatible (at least with the non-bevel gears, but the traditional spur gears). I am excited about the potential of interacting with existing Technic parts!

scott-smith_us 5y ago
Ah. I wondered about their choice of chain type vs a ball/bead chain. Now it makes sense.
worldsayshi 5y ago
Wow, that's a nice feature!

gugagore 5y ago

There are two possible mechanical analogies to electrical circuits (https://en.wikipedia.org/wiki/Mechanical%E2%80%93electrical_analogies https://en.wikipedia.org/wiki/Mechanical%E2%80%93electrical_...). In domains (electrical, acoustic, thermal, mechanical, ...) there are two kinds of quantities, sometimes called "across" (voltage, temperature difference, ...) and "through" (current, heat, ...). 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.

colanderman 5y ago
Interesting, I'm curious why this analogy was chosen, and not the other way around. Current as torque and voltage as (rotational) velocity would seem to allow the junctions to be much simpler -- just a gang of gears on a single axle, rather than the differential mechanism used here -- since torques (like current) add at an axle/junction, while rotational velocity (like voltage) transmits through an axle/junction. 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.
- mdiesel 5y ago

Animats 5y ago

Oh, that's precious. I hope they ship this, and that the components aren't too expensive. They look expensive.

ajarmst 5y ago

I was a backer for their previous project: Turing Tumble. It was a very positive experience, with timely informative updates and ultimately a high quality product.

spoonjim 5y ago
Turing Tumble is so great.

spoonjim 5y ago

I was going to say “this better be as good as Turing Tumble!” Now I see it’s by the same guy. BUY

deleted 5y ago

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d--b 5y ago

This is great! I didnt even know there were mechanical analogs to electronic parts. This is going to make electronic teaching an awful lot mote intuitive!

c-smile 5y ago
There are also such things as "pneumonics" and "fluidics" : https://en.wikipedia.org/wiki/Fluidics https://en.wikipedia.org/wiki/Fluidics 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.
hellbannedguy 5y ago
The USA should start teaching electronics in third grade, and through high school. Don't even grade the kids. I think it's more important ever for kids to know. 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?

hintymad 5y ago

This is amazing and looks fun! I immediately paid to support the project, so I can play the toy later. 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.

krastanov 5y ago
I teach and from my experience drive and aptitude is not the problem. "Math" and "abstraction" are not the problem either, except that for many educators they are synonymous with rote memorization which leads to ridiculous amounts of math phobia in the US that I have not seen in Europe. 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.

spoonjim 5y ago

To the founder’s point about math not being necessary for developing intuition about electronics: Michael Faraday’s three volume treatise on electromagnetism, which essentially created the entire scientific field, has essentially zero math in it.

pontusrehula 5y ago

The heading seemed contradictory to me with both "spintronics" and "mechanical" in it until I realised that it is not the other sprintronics (https://en.wikipedia.org/wiki/Spintronics https://en.wikipedia.org/wiki/Spintronics).

Pet_Ant 5y ago
Yes I and pedantically bothered by the fact that it isn't really about spintronics nor electronics, but rather mechanical engineering and merely co-opting a more marketable term... that said I'll still buy a copy for my kids. Already playing LaserMaze with them. Even if they don't end up in stem I hope it helps in their A levels one day. https://www.thinkfun.com/products/laser-maze/ https://www.thinkfun.com/products/laser-maze/

ofou 5y ago

Where is the memristor?

oceanghost 5y ago

Amazing. I have a friend whose building a logic system for marble runs-- think and/or/xor/nor gates made with marbles. I love stuff like this.

ZeikJT 5y ago
Might want to point them at Turing Tumble, another project by the same creators. https://www.turingtumble.com/ https://www.turingtumble.com/

scott-smith_us 5y ago

In high school I took electronics and learned enough about capacitors, inductors and transistors to design and test simple circuits. I'd gotten a Radio Shack "100-in-1" kit when I was in fifth grade, but the projects within were all opaque recipes to me. Most circuits had illustrations with cartoons components saying things like "I'm the capacitor, and I give a little 'kick' to the transistor!". I remember being kind of surprised at just how un-enlightening these cartoons were. If I followed the wiring steps for a project and then it didn't work, I'd double-check my wiring. If it still didn't work, there was nothing further to do; I just gave up. I had no idea how it 'ought' to work, so there was nothing I could measure or verify that would mean anything to me. 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!

amelius 5y ago
Another approach would be to have capacitors with little leds on them which show charge, leads with little leds which show current, etc.

kizer 5y ago

You'd think the water analogy would be easier to build and sell. Regardless, the more "analogies" the better, as the abstract concept reveals itself more readily. 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 :(