The Analog Thing: An open source, educational, low-cost modern analog computer

by ktpsns • 5 years ago

136 65 5 years ago

smoldesu• 5 years ago

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!

jpm_sd• 5 years ago

The name is not great and it seems like the target market is probably already served by breadboards?

detaro• 5 years ago

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• 5 years ago

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.

retrac• 5 years ago

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.

dugmartin• 5 years ago

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• 5 years ago

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• 5 years ago

For 300 Euros they could've at least integrated one of those cheap ARM-based DSO oscilloscopes.

MisterTea• 5 years ago

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.

louthy• 5 years ago

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.

spicybright2• 5 years ago

How do logic gates work? Does that just use a threshold for T/F, then turn it "digital" with a high and low value?

motohagiography2• 5 years ago

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• 5 years ago

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.

motohagiography2• 5 years ago

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.

tiborsaas• 5 years ago

Now you gave me some hope that the massive time that went into Reason was not wasted :)

chas• 5 years ago

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

pvitz2• 5 years ago

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.

buescher5• 5 years ago

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.

pjc50• 5 years ago

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.

atoav2• 5 years ago

Zener reverse avalanche noise + sample and hold?

PavleMiha• 5 years ago

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• 5 years ago

The quote is saying that digital computing faces cyber threats, which makes analog computing inherently safer. Not that analog computing faces cyber threats.

spicybright2• 5 years ago

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.

md2020• 5 years ago

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• 5 years ago

Any beginner's book about OpAmps will get you started.

buescher5• 5 years ago

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/

jsilence3• 5 years ago

Install VCV Rack and watch Omri Cohens videos. Warning: you might fall deep into this magnificen beautiful rabbit hole.

Schiphol2• 5 years ago

Slightly OT: Does anyone know of a textbook or other resources where (dis(advantages of analog vs digital computing are discussed?

mindcrime• 5 years ago

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

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.

carapace• 5 years ago

"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...

lambdatronics2• 5 years ago

There's a fairly simple reason for the superiority of digital computing, which is that error accumulation in analog is impossible to avoid, so the accuracy of results is limited by the quality of the components, which makes them large/expensive and even then maybe only 1% accurate. Programming them is less flexible, too. The applications are pretty niche.

The analog advantage is that you can directly implement differential equations, so they can be more power-efficient and faster than the equivalent digital simulation.

Schiphol2• 5 years ago

Thanks for this. I am most interested in mathematical comparisons. That is to say, ways in which optimal analog computation (idealizing away from noise propagation, among other things) might be sometimes better than its digital counterpart. Your last point about diff equations is directly relevant to this.

mdp20212• 5 years ago

With "The Analog Thing", you can model dynamic systems including: ° market economies; ° the spread and control of diseases; ° population dynamics; ° chemical reactions; ° mechanical systems; ° a variety of mathematical attractors

glitchc• 5 years ago

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.

throwawayboise• 5 years ago

One of the features listed: "An interface for controlling THAT digitally to develop analog-digital hybrid programs"

buescher5• 5 years ago

A permanent analog computer is just an analog circuit. You can build a PCB with op-amps after you've proved it out.

mpfundstein• 5 years ago

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• 5 years ago

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.

nereye• 5 years ago

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.

munificent4• 5 years ago

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• 5 years ago

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.

jazzyjackson• 5 years ago

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

jsilence3• 5 years ago

Might want to look into the Bespoke Synth.

lambdatronics2• 5 years ago

You're describing a 'field-programmable analog array' (FPAA), the analog equivalent of an FPGA.

atoav2• 5 years ago

So you are telling me this is a synthesizer?

munificent4• 5 years ago

Without any oscillators. :(

jsilence3• 5 years ago

Does the filter ring?

Animats• 5 years ago

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.

Stampo00• 5 years ago

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.

friendly_chap• 5 years ago

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 ?

the_only_law• 5 years ago

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.

analognoise• 5 years ago

I am super excited to buy one of these.

mycall• 5 years ago

This is way better than my Radio Shack 200-in-1 for understanding the logic part better than jumping directly to resistors/capacitors/diodes/etc. What a time to be alive.

giardini2• 5 years ago

Why wouldn't someone write a digital simulation of "The Analog Thing" and sell it?

hulitu• 5 years ago

Because you need an analog to digital converter.

giardini2• 5 years ago

Most analog systems today are digitally simulated. No ADC is required.

The Analog Thing: An open source, educational, low-cost modern analog computer

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