Fluid Logic Chips

Doc Ruby writes "Colorado researchers 'have constructed microfluidic gates that use the relative flow resistance of liquid to carry out the basic logic operations NOT, AND, OR, XOR, NOR and NAND. The researchers have also combined a pair of gates into a half adder, which carries out half the operation of addition.' All CPUs processing binary logic are made of these types of gates, but usually execute as flows of electrons in wires, not fluids in tubes. Will this advance revolutionize chemistry and computing the way electric gates revolutionized electronics and computing? Will 'fluid programmers' give new meaning to "flowchart"?"

Comments

How fast?

[cbrocious]

How fast could this ever be? Neat, but I dunno how this could ever be put to a practical use. Cool hack none the less.

Re:How fast?

[ikewillis]

I think you mean the speed of electrons. Electrons can't travel the speed of light (in a vacuum)

Re:How fast?

[wass]

Practical uses? Well, for starters, it's microfluidics. So if we're lucky, we'll finally be able to get one of these babies into a package small enough to fit in a watch. You've always wanted a digital watch, right?

It's amusing, but in 1967 this Fluidic Amplifier was billed as "the simplest device known for setting up digital circuit applications."

Re:How fast?

[grumpygrodyguy]

Will this advance revolutionize chemistry and computing the way electric gates revolutionized electronics and computing? Will 'fluid programmers' give new meaning to "flowchart"?"

How fast could this ever be? Neat, but I dunno how this could ever be put to a practical use. Cool hack none the less.

In all likelyhood this will never be used as a replacement for silicon. It's much more likely that stuff like this will be used in bioinformatics & pharmacuetical circles in order to perform massively parallel tests on different molecular combinations.

If there are over 1,000,000 molecular permutations of a particular family of drugs(or DNA). Perhaps this kind of computer could rapidly cycle through all such combinations. Maybe the testing reaction could be performed with a liquid-mechanical ALU of sorts. Then the results could be stored in a liquid memory bank where they could be reviewed. Perhaps indicator dyes, or electrical dyes could be used to signal positive/negative results. *shrug*

Re:How fast?

[hunterx11]

You've always wanted a digital watch, right?

That and little green pieces of paper.

Re:How fast?

[wass]

Speed of light in vacuum, c, will always be faster than the speed of propogation of any particle, mode, or disturbance**.

The speed of light in a material is slower than in a vacuum, by a factor of the index of refraction (usually frequency dependent). Interestingly, it IS possible for particles to travel faster than this apparent speed of light, and in doing so they emit Cerenkov Radation, which is how many high-energy physics particle detectors (eg SNO) detect individual particles.

** For the nitpickers who will inevitably respond to that generalization, it is occasionally possible (in theory, at least) to set up a mode in some carefully-devised system where the speed of propogation of this mode is faster than c, but this mode cannot carry information. Simple example is a linear array of equally-spaced pendula, each with the same fundamental frequency, and with a spring connecting the weights at the bottom to the two pendula on either side. If a mode is set up where all pendula are oscillating at their fundamental frequency, all of them at exactly the same phase, (springs always remain at their unstretched length) then the phase velocity of this mode is infinite. However, there can be no 'information' or disturbance transmitted down the system. In reality, thermal and quantum disturbances would disrupt this mode and it would eventually become something much more complicated. These disturbances would be transmitted at a finite velocity, less than c.

Re:How fast?

[polecat_redux]

that is still a lot faster then we can move an object bigger then an atom.

True, but you wouldn't necessarily need to move a specific liquid molecule through an entire path/circuit. For example, say you have a tube filled with water, and you were to apply pressure on one end, almost instantly, water would be expelled from the other end. The "distance" that any single molecule of water along the path would need to travel depends only on how much water you want to get out of the other end.

For lack of a better analogy, it would be like poking someone with a stick rather than throwing a rock at them - travel time is mostly eliminated.

Re:How fast?

[Jerf]

almost instantly, water would be expelled from the other end.

You can quantify that better. It basically travels at the speed of sound in the medium, because it uses the same forces that sound does.

This is also the solution to the relativity paradox, "What if I take an infinitely rigid rod and tap it on one end, causing the other end to instantly vibrate, with the tap exceeding the speed of light?" The answer is that in this universe, no such infinitely rigid rod is possible; the maximum speed possible is still the speed of light.

This also implies that fluidic computing will always be slower than electronics, because the fundmental speed is orders of magnitudes slower. Which doesn't mean it is useless, I'm just killing two birds with one stone here, showing why this is no threat to electronics :-)

Re:How fast?

[wass]

You, sir, are a moron. They didn't invent a new mechanism for transmitting a signal. Electrons _have_ to be used.

This seems to be a common misperception on slashdot.

Electrons are certainly used, of course, in digital logic circuits. For example representing bits as charge stored in a capacitor, or by mediating the quantum statistics of a transistor for switching (by controlling the charge on the gate of a MOSFET).

However - when a signal is sent down a wire (eg, from a microprocessor, over the data bus, to a peripheral) that signal is NOT being sent through the electron drift. [Although electrons will drift in presence of an electric field, the drift velocity is INCREDIBLY small, look it up.]

If the microprocessor wants to flip a bit from a 0 to a 1, the wire is originally at one potential, and the microprocessor will change the potential. This disturbance isn't instantaneous along the wire, that would violate relativity. The microprocessor basically creates an electromagnetic disturbance that travels down the wire to the peripheral.

Now let's look at this 'disturbance' more closely. Electrons at point A are being ultimately effected by electrons at point B. This effect is mediated through electron interactions, and one knows that that the electromagnetic force is the mediator between electrons. And from Quantum Field Theory one knows that photons are the quanta of the electromagnetic force.

So what this in effect means is that whenever electrons are interacting, photons are being transmitted somewhere during that exchange. Thus, the parent was correct that it's the electromagnetic wave, as opposed to the physical motion of the electrons themselves. that plays the role in limiting digital logic speed.

Re:How fast?

[wass]

it uses the same forces that sound does.

Actually, if you look at the microscopic physics, they both use the same forces. It's primarily electromagnetic forces, although some quantum degeneracy statistics plays a role too, that prevent your hand from going through a door when you knock on it. However, in fluidics (and sound) phonons are being transmitted through the medium, just like photons are transmitted through the wires in electronic systems. However, the sound waves derive mostly from the usually harmonic potentials keeping molecules spaced apart at their average distances. EM waves derive from charges (ie, electrons) moving and reacting with each other.

This also implies that fluidic computing will always be slower than electronics

Practically yes, but to be pedantic - not necessarily always. Maxmimum signal speed in fluidics would by governed by phonons, and in electronics by photons.

In reality the phonon modes, which are usually pretty dispersive (ie propogation speed depends on frequency), have slower propagation speeds than photons (also usually dispersive but usually not as much) in most matter.

But to say 'always' isn't necessarily true, there's no reason a priori to assume in some random material photonic excitations are necessarily faster than phononic excitations.

Redundant Systems and Fluid Dynamics

[mfh]

Will this advance revolutionize chemistry and computing the way electric gates revolutionized electronics and computing?

Not really, because it's basically a copy of the old way except utilizing fluid dynamics. The way electric gates revolutionized electronics was special because there was nothing like it before. What this will do, is enable better redundant designs for deep space probes. Also, a liquid computer likely doesn't get as hot or it won't be as much of a problem if it does.

Will 'fluid programmers' give new meaning to "flowchart"?"

No, we'll just fill all the systems with coffee and call ourselves The Happy Folk.

So in the future

[Camel Pilot]

Will we have computers with a logo that says

"Guinness inside"

In Eastern Germany

[retostamm]

in the 1970's there was a lot of research on Pneumatic Computing. I read a book about that a while back (can't remember the title).

Essentially it worked the same way, plus they had a little "Transistor" where a big airstream would be disturbed if a small control airstream is on.

Obvious advantages of that technology:
- You only need to be able to cut sheetmetal and weld it together
- Not affected by X-Rays unless you melt it (think MAD/Nukes)
- Probably no cooling problems (not sure about this)

Of course, it'd be also very slow. And big.

chemistry and computing?

[k98sven]

Will this advance revolutionize chemistry and computing the way electric gates revolutionized electronics and computing?

I'm not sure if this is a typo.. but I see no real use for this in computing.. unless you want computers which (at best) work like conventional ones except much, much, much, slower.

However, in chemistry.. it may very well become a big thing. One possible use I can think of is for building automated little microlaboratories, controlling the mixage and flow of different chemicals.

This, in general, is a hot research topic in chemistry.. Already in biotech a lot of things similar to this are being put to practical use (Chip assays is an example).

Basically, it's the revolution of miniaturization which is (finally..) coming to chemistry.

Advanced? This is 50's technologies

[nurb432]

The application of fluidics has been around for ages.. even before tubes and 'electronic logic' we had fluidics.. both analog and digital.

Sure its still cool, but dont call it 'advanced'..

Geesh..

Cool Running

[overshoot]

Hate to break the news, but unless someone finds a way to use superfluids (lossless flow fluids, like liquid helium) for these, they're gonna take power to run.

At a rough guess from scaling theory, they're gonna take several orders of magnitude more energy/bit than electronic gates.

Re:It's not like this is new logic...

[NanoGator]

"This is a new way to do binary logic mechanically, but until they get this to the speed of copper chips they're not going to be useful for much."

Would they survive an EM burst?

Re:Sounds great but...

[k98sven]

The width of these channels is 100 micrometers.

The flows here are created by the capillary forces which dominate at that size.

No gravity required.

There are still some bugs in the water gates...

[hpa]

Okay, this definitely calls for a link to... Crunchly!

Mandatory reading for the larval geek...

Fluid computer in Cold War?

[isdale]

I recall there was a ballistics computer built back during the cold war. The idea was that it was immune to radiation effects (EMPulse). I cant find a reference to it in a quick web search.

Corning fluidics (from about 1972)

[klubar]

Many years ago (about 1972), Corning and others made "fluidics" devices that used air to implement simple nand gates. They were looking for applications, such as explosive environments (fireworks factories, cotton processing) that relays wouldn't work well in. The devices had simple sensors and could implement logic by combining nand gates. There were a couple of competitors that made fluidic devices. The Corning were small black cans about 2" high and 1/2 around; the air supply was connected on the top and there were 4-inputs and one output on the bottom.

Cute, but they went no where. I put together a neat high school science fair project with them and got to the county level.

Nice to see the concept recycled.

I swim the body fluidic.

[Doc Ruby]

That could depend on the operations. In the electronic paradigm, fast CPUs process data in parallel, integrated across much slower networks, their messages processed by routers on a much higher symbolic level than processed in the CPUs. A possible fluidics architecture might process chemical reactions which code their results in their products, which are flags for the fluidic processor valve. So networks of partial results can be processed by these CPUs. There are many computational chemistry applications which could be complementary to this kind of processor, with fluids merely the medium which they chemistry conveniently produces, and these chips are suited to process. There's nothing uniquely informational about electrons; they're just the tiny tool we had mastered when we started applying the mechanics of info theory. Now we can harness our latent fluidics techniques, crossbred with our electronic techniques, for a hybrid that can use the most tractable properties of both.

Additionally, humans are more chemical than electronic. Even our neurology, often metaphorically "electric", is really an ion pump. All electronics require lots of adapters to couple with our senses, either chemical, optical or mechanical (including sound). These fluidics are in the same domain as our own primary physical existence. So integrating them with our biology might be more direct. Implants, sensors, medicine, all the much more personal tech applications might be more available to microfluidics than they've been to alien electronics. Surf's up!