[HN Gopher] The Analog Thing: An open source, educational, low-c...
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The Analog Thing: An open source, educational, low-cost modern
analog computer
Author : ktpsns
Score : 118 points
Date : 2021-09-22 10:38 UTC (12 hours ago)
(HTM) web link (the-analog-thing.org)
(TXT) w3m dump (the-analog-thing.org)
| atoav wrote:
| So you are telling me this is a synthesizer?
| munificent wrote:
| Without any oscillators. :(
| jsilence wrote:
| Does the filter ring?
| glitchc wrote:
| While this is a cool idea, it's not terribly useful for anything
| more complex than a toy example. The fact that I need to
| physically wire the components and manually adjust coefficients
| every time I create a new program means that I can only really
| leave one complex program configured at a time. How do I switch
| between programs? Do I buy new THATs then?
|
| It would be much more practical if the analog components could be
| configured digitally through a script, so that multiple programs
| could be constructed and run on the same compute platform. A
| hybrid platform of sorts.
| nereye wrote:
| From a mainstream perspective, there are mixed mode ICs that
| contain a bunch of analog components (op amps, comparators,
| etc.) and allow you to configure them digitally. E.g. the whole
| PSoC series from Cypress (formerly, now Cypress is part of
| Siemens).
|
| Slightly less mainstream, there is the concept of FPAA (field
| programmable analog array), which is the equivalent of an FPGA
| but for analog instead of digital.
|
| E.g. see https://www.anadigm.com/fpaa.asp.
| jazzyjackson wrote:
| i'm not sure how to find the photos but on some old analog
| computers, the entire patch board is swappable. to run a
| program, you would choose from your physical library of patch-
| boards.
|
| kind of like moving an AVR chip from one breadboard to another
| throwawayboise wrote:
| One of the features listed: "An interface for controlling THAT
| digitally to develop analog-digital hybrid programs"
| jsilence wrote:
| Might want to look into the Bespoke Synth.
| munificent wrote:
| _> The fact that I need to physically wire the components and
| manually adjust coefficients every time I create a new program
| means that I can only really leave one complex program
| configured at a time._
|
| This is basically the reality of every musician making music
| with guitar pedals and modular synthesizers. And the answer is,
| yes, you physically make the thing you want. Once you're done
| with it, you tear it down to make the next thing. That's part
| of the magic.
|
| It's like building something out of LEGOs. If you want to re-
| use the pieces, you need to take apart your creation.
| nextaccountic wrote:
| Why can't it work like an FPGA? I set the coefficients in
| software, it programs the analog computer through a serial
| interface, and then I don't need to tweak knobs every time I
| want to change something.
| regularfry wrote:
| It can do. Digital switching of analogue signal paths can
| absolutely be done. MAX335/336/337-type chips are one way
| of doing it, and they've been around for decades.
| buescher wrote:
| A permanent analog computer is just an analog circuit. You can
| build a PCB with op-amps after you've proved it out.
| mpfundstein wrote:
| so in your mind, are FPGAs also only useful for toy examples?
| also, how often do you think a pcb of an electrical product
| changes once deployed?
| djur wrote:
| FPGAs are certainly far more useful due to the fact that you
| can design and simulate them digitally and then mass produce
| them from that design. You can work on as many FPGA designs
| as you want in parallel without having to physically set up
| and tear down each one in turn.
|
| They also don't cost $350 a pop.
| friendly_chap wrote:
| Pretty cool. Typo on frontpage
|
| > As digital computing approaches the limit of Moore's Law,
| analog computing offers a strategy to diversity today's digital
| monoculture.
|
| s/diversity/diversify ?
|
| s/today/in today ?
| Schiphol wrote:
| Slightly OT: Does anyone know of a textbook or other resources
| where (dis(advantages of analog vs digital computing are
| discussed?
| carapace wrote:
| "Why Analog Computation?", oldie but goodie unclassified NSA
| document.
|
| > An introduction to analog computation containing a brief
| description of the analog computer and problems in which it can
| be advantageously applied. Both analog computers and systems
| combining analog and digital techniques are discussed in order
| to show why the Agency's interest in this computation area has
| increased.
|
| https://www.nsa.gov/Portals/70/documents/news-features/decla...
| mindcrime wrote:
| I looked a while back, and it seems that most books on the
| topic fall into one or the other of two categories:
|
| 1. Really old, and really expensive
|
| or
|
| 2. Somewhat modern, and also pretty expensive
|
| FWIW, here's an Amazon List on this topic that I put together a
| while back. Looks like there are one or two that can be had for
| fairly cheap, if used copies are acceptable.
|
| https://www.amazon.com/hz/wishlist/ls/1ZGZWA01QFE1V?ref_=wl_...
|
| I wound up snagging a couple off of a pirate e-book site but
| haven't had time to really dig into the whole thing yet.
| Animats wrote:
| It's cute, but, having used analog computers, it lacks some
| important things. Analog computers are usually reset to initial
| conditions, then started. As time goes on, the outputs change.
| This thing has integrators, so it will generate time-varying
| outputs. You need some way to watch those time-varying outputs,
| such as a plotter or an oscilloscope. This needs a graphical
| display. Something like one of those US$20 digital oscilloscopes
| available on Alibaba.
| analognoise wrote:
| I am super excited to buy one of these.
| motohagiography wrote:
| This is amazing. I use the MakeNoise Maths module on my synth to
| experiment with similar ideas, as I think the next leaps in
| scaling quantum computing are going to come from a generation of
| kids who developed a musical level intuition for wave dynamics
| playing with their parents' analog synths.
|
| Digital has been cool and interesting, but when young hackers
| have the tools and incentives to become de-facto physicists,
| they're going to tear holes in the fabric of reality. This is
| such a cool product.
| jnovek wrote:
| OK, this is increasingly off-topic, but I'm just getting into
| Eurorack and I've been become curious about analog computers...
| not because I know anything about them, but because they share
| a user-interface style.
|
| Can you speak to similarities between them? You seem to know a
| bit about both topics.
| motohagiography wrote:
| Thanks! With the caveat that I profoundly lack depth on both,
| and am a bit artsy craftsy in my intuitions, I did buy the
| Maths module precisely because it was an analog computer.
|
| The intent was to create some generative music, and seeing if
| I could use it to create 1/f noise, and exploring self-
| similarity using a musical ear instead of in code. Still
| working on it.
|
| When you look at what you can do with magnets hooked to a
| synth with a ferrofluid, e.g. https://youtu.be/Q3oItpVa9fs ,
| the sound and your ear helps to develop an sense for what
| kinds of waves can be used to yield physical effects. If you
| can functionally suspend and maipulate a ferrofluid with
| waves, there are likely analogies to laser pulses and
| electrons for quantum computing. Waves gonna wave, etc.
|
| The other piece that grabbed me recently was "analog
| fractals," (https://hackaday.com/tag/analog-fractals/ + that
| rabbit hole) where if you can get those artifacts
| instantaneously as the effect of physical feedback instead of
| rendering them computationally, there are likely faster
| functional approaches to a lot of other problems, only a
| subset of which we use ASICs and FPGAs to implement today.
|
| It's speculative based on laughably incomplete understandings
| on my part, but that's hacking.
| chas wrote:
| One thing to note: the waves in quantum physics have complex
| amplitudes[0] (e.g. a real number + an imaginary number),
| rather than the waves in most synthesizers and analog computers
| which only have a real amplitude. This means that they can have
| very different behavior e.g. wave interference is different for
| real-valued classical waves and complex-valued quantum waves.
| Experience with any wave dynamics is certainly still valuable
| though.
|
| [0]https://physics.stackexchange.com/a/46054
| tiborsaas wrote:
| Now you gave me some hope that the massive time that went into
| Reason was not wasted :)
| pvitz wrote:
| The last time this came up, I spent some time investigating the
| use of analog computers for Monte Carlo simulations and it is
| absolutely fascinating how differential equations or stochastic
| differential equations are being implemented with analog
| components. There are already some chips available that integrate
| these components similar to FPGAs and some toy examples show
| promising results, but it looks like we are not completely there
| yet. Nevertheless, if these chips get further developed, they
| could have a huge impact on neural networks (at least in terms of
| power consumption) and maybe Monte Carlo.
| buescher wrote:
| That would be really interesting - how do you generate the
| randomness?
|
| Every so often when Matlab or Simulink won't integrate
| something simple, probably because of something I did, I wish I
| had an analog computer to compare to.
| atoav wrote:
| Zener reverse avalanche noise + sample and hold?
| pjc50 wrote:
| Randomness is impossible to eradicate from the analogue
| world, so you just take an existing noise source like a
| semiconductor junction and connect it to an amplifier.
|
| Some care is needed to get something that works across a wide
| temperature range, and avoids being easy to overwhelm with
| outside noise sources, but it's a problem with lots of
| existing solutions.
| buescher wrote:
| I mean in a practical way for a monte carlo simulation -
| usually in analog setup you set parameters with discretes,
| so you are going to need to do things like feeding a
| transconductance amplifier with your noise source. You're
| also going to worry about shaping and otherwise
| parameterizing your distribution - do you need uniformly
| distributed noise? gaussian noise? what are your limits?
|
| I can imagine a lot of practical pitfalls and awkward half-
| solutions to trying to do an analog monte carlo; I was
| wondering how the OP went about it.
| pvitz wrote:
| There is actually a fascinating thesis by Yipeng Huang
| ("Hybrid Analog-Digital Co-Processing for Scientific
| Computation") that discusses toy models (i.e. Black-
| Scholes and variants).
|
| As usual, you have a Wiener process and thus need
| Gaussian noise. Yipeng Huang found that some noise
| stemming from a resistor ladder of the chip provided
| Gaussian white noise and he could control the mean by
| feeding it with a DAC and he also had some way to control
| the variance by changing some multipliers (but I can't
| tell you exactly how that worked). Nevertheless, this was
| the analog part and he faced issues with DC drift.
| Alternatively, he looked into generating the noise
| digitally with a microcontroller.
| buescher wrote:
| Thanks - the thesis does look interesting.
| PavleMiha wrote:
| This looks really cool, I found the line "inherently safer than
| digital computing in the face of cyber threats" pretty funny.
| There's no analog internet so what could the cyber threats even
| be?
| jaywalk wrote:
| The quote is saying that digital computing faces cyber threats,
| which makes analog computing inherently safer. Not that analog
| computing faces cyber threats.
| spicybright wrote:
| I feel like that's a silly claim though. If you have no
| networking, wireless, interface for loading code, or really
| any code at all, then of course it's more secure.
|
| You're not doing the same tasks as a digital computer though.
|
| Paper is more secure than digital computing.
| mdp2021 wrote:
| Exactly. And the claim stands, that if you can effectively
| compute (<<model dynamic systems>>) through an analog
| computer, you expand your toolbox with items that are
| beyond a framework involving security issues. (Yes, like
| paper, but paper, while it helps the computer, does not
| compute.)
|
| Another rephrasal of the concept they are proposing: "Don't
| be the man with a hammer" [not all problems are to be
| treated as nails - including the health and safety related
| concerns nails demand].
| pjmorris wrote:
| I've joked for a number of years that I expect to see
| boutique professional offices (lawyers, doctors, dentists,
| etc) springing up that offer 'paper records only' as a
| feature.
| md2020 wrote:
| This looks awesome, but as someone who knows nothing about analog
| computing, what's a good educational resource to go along with
| this so that I can use it to actually learn?
| amelius wrote:
| Any beginner's book about OpAmps will get you started.
| jsilence wrote:
| Install VCV Rack and watch Omri Cohens videos. Warning: you
| might fall deep into this magnificen beautiful rabbit hole.
| buescher wrote:
| Analog computing is about making analogs (today we would say
| usually say simulations) usually of physical systems, usually
| with operational amplifiers.
|
| Learn to model physical systems with differential equations
| first (and in 2021 you will probably also learn to
| solve/integrate them numerically on a computer in the process)
| then go to op amps.
|
| Here are some other interesting problems you can solve with
| analog computers that aren't really modeling problems, though:
| http://dataphys.org/list/dewdneys-analog-gadgets/
| Stampo00 wrote:
| This is so fascinating. I'll be keeping an eye on this. I've been
| doing binary computing all my life, so it's kind of mind bending
| to think of computing using analog circuitry without immediately
| trying to turn it back into binary again.
| the_only_law wrote:
| > As digital computing approaches the limit of Moore's Law,
| analog computing offers a strategy to diversity today's digital
| monoculture.
|
| What sort of industrial roles/domains is analog computing
| particularly fit for. And whats the cancer that we see them
| adopted either replacing or alongside digital computers in those
| roles.
| mdp2021 wrote:
| > _With "The Analog Thing", you can model dynamic systems
| including: deg market economies; deg the spread and control of
| diseases; deg population dynamics; deg chemical reactions; deg
| mechanical systems; deg a variety of mathematical attractors_
| smoldesu wrote:
| I love devices like this, buying a Behringer Neutron completely
| opened my eyes to the possibilities of patching on a bigger level
| than just music.
|
| I do have to wonder who would buy this though. Analog computers
| like this are virtually useless unless you have some particularly
| applied use-case for them. I'd be interested to hear some user
| testimony if anyone owns one of these!
| dugmartin wrote:
| I think they missed the mark only having a single lcd panel for
| output. I think a grid of leds, maybe 10x5, with each column
| having an input jack and a dial to set the range would allow
| much better visualization. That is a lot of extra parts though.
| opwieurposiu wrote:
| The LCD voltmeter is used for precisely setting coefficients,
| to view the output you need some kind of scope. This is
| typical of most analog computers.
|
| https://the-analog-thing.org/wiki/Oscilloscope
| nullsmack wrote:
| For 300 Euros they could've at least integrated one of those
| cheap ARM-based DSO oscilloscopes.
| louthy wrote:
| > Analog computers like this are virtually useless unless you
| have some particularly applied use-case for them. I'd be
| interested to hear some user testimony if anyone owns one of
| these!
|
| You've already highlighted a clear use-case. The Neutron is a
| semi-modular analogue synth. The whole modular-synth scene is
| based on this kind of analogue computing, when I look over at
| my eurorack modules, I have:
|
| * Function generators
|
| * Gates
|
| * AND/ OR / NOR / XOR / NAND / XNOR
|
| * Summing
|
| * Multipliers
|
| * Comparitors (generate a signal based on conditions)
|
| * And more!
|
| That pretty much covers everything in 'The Analog Thing'
| computer.
| spicybright wrote:
| How do logic gates work? Does that just use a threshold for
| T/F, then turn it "digital" with a high and low value?
| denton-scratch wrote:
| Gates are built using transistors that are designed and
| biased so that they "threshold" themselves. You can just-
| about rig a gate so that it's output will be uncertain; but
| in general, gates are not amplifier circuits with some kind
| of threshold on the output. They are intrinsicaly
| electronic switches.
| munificent wrote:
| Yes. Logic gates are essentially the bridge between the
| analog and digital world. Your digital computer is
| ultimately based on analog components that use thresholds
| and high-low voltages.
| [deleted]
| MisterTea wrote:
| > Analog computers like this are virtually useless unless you
| have some particularly applied use-case for them.
|
| Did you miss the educational part?
|
| Electronics is physical math. Amplifiers are a perfect example,
| take an input and multiply it. Resistors can be used to
| subtract or divide. Combining these functions is how an op-amp
| works. Combining more components now allows you to do
| integrals, derivation, and other functions.
|
| From there you take these basic building blocks and apply them
| to real world problems like audio amplification, processing and
| filtering. Of course a lot of this is replaced by digital stuff
| but digital has one huge disadvantage: obsolescence. I can
| repair a 40 year old analog amplifier. I cant repair a 10 year
| old stereo with a dead ASIC or DSP/SoC.
| jpm_sd wrote:
| The name is not great and it seems like the target market is
| probably already served by breadboards?
| detaro wrote:
| > _it seems like the target market is probably already served
| by breadboards?_
|
| I doubt it, assuming the analog groups are well-designed
| that's not trivial to just replicate in a DIY breadboard
| circuit.
| JKCalhoun wrote:
| Because it is an analog computer it is a kind of breadboard
| though, isn't it? ;-)
|
| No, having all the Op-Amps wired up for me, powered for me,
| "nulled" for me is a huge improvement over the mess I would
| have to make on a breadboard to replicate even a part of it.
|
| I only wish it had more than one output (meter) component so
| I could observe steps along the way.
| madengr wrote:
| I'd prefer an analog meter.
| retrac wrote:
| The site emphasizes the educational aspect. I think they have a
| point. Nothing teaches mathematical relationships like hands-on
| instant feedback from a physical system. Patching your program
| and turning knobs in a literal sense jives well with the naive
| mental physics model some of us rely heavily on for reasoning
| and learning.
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