Water Computing

Andrew_Cronin writes "This is a nice project that some one did at MIT on building some logic computation systems without using electrons.. So why not use water..."

Comments

10 electrons in H20

[zedge]

So it is not exactly true that they
are computing without electrons.

Cool...but an old concept

[dillon_rinker]

Scientific American had an article about water-based logic gates and circuits some decades ago. IIRC, they even created circuits that had no electronic analogy. I can find no reference to this on the web - perhaps some other science geek with access to a complete collection could find it. I believe it was in the Amateur Scientist, but it's been about fifteen years since I read through the stacks of magazines in the cabinets of my chemistry classroom, so I could be mistaken.

For a similar concept (ie, non-silicon machine logic) that I first read about in the pages of Scientific American, check out the Apraphulians here . For more info on this ancient race, Google is your friend.

Re:Cool...but an old concept

[FozzTexx]

i seem to recall something about logic gates or some sort of logic being built out of matchboxes and beans. it played tictactoe, deciding the best move by plopping out a bean of a certain colour? i can remember neither the details nor the source.

I've seen it in a book by Martin Gardner, the game was called Hexapawn. A quick search on google should turn up more details.

Re:Cool...but an old concept

[McCart42]

Speaking of logic, here's a October 1989 Scientific American article detailing the tinkertoy tic-tac-toe playing machine. Anybody want to make this out of these water logic components? Didn't think so... ;)

Re:Cool...but an old concept

[anonymous loser]

The "apraphulian computer" article in 1988 was an April Fool's joke. A.K. Dewdney has a history of presenting interesting scientific concepts as fiction. You can find examples of this style of presentation in his book Planiverse as well as some of the earlier corewars articles in Scientific American IIRC.

umm.... this is news?

[eclectric]

The "idiots guide to computers" class I was forced to take in college included this project as an example of how logic circuits work. And they one they had was more complex. And it used kool-aid. I've seen this project in at least 10 CS departments. Dammit, this is not news. This would be better if it was a four digit binary adder.

Re:But what about...?

[Anonymous Coward]

how to implement other operation: OR, NOT

Simple. The author gives XOR and AND gates, formed from joining two streams together, without and without a control. (See the article for details, I haven't taken the time to look into it very deeply).

Anyways, XOR's function number is 0110. Split it in two, and you get "A(01) when B=0, NOT A(10) when B=1"--two unary gates formed a binary gate. Split AND's function, 0001, and you get "0 when B=0, A when B=1". Trust me, this is easier than it seems. The unary gates are: 00=0, 01=B, 10=NOT B, and 11=1. Now that we got that out of the way:

• 0 XOR A = A
• 1 XOR A = NOT A
• 0 AND A = 0
• 1 AND A = A

None of those are useful except 1^A=!A. We need NOT to complete our library of functions too. Now we can combine it with other gates like so using Boolean Algebra:

NOT(A XOR B) = A XNOR B
NOT(A AND B) = NOT(A) OR NOT(B)DeMorgan's Law
NOT(A AND NOT(B)) = NOT(A) OR NOT(NOT(B)) = NOT(A) OR B
And now, ladies and gentlement, I present to you, The OR Gate:

not(not(a) and not(b)) = not(not(a)) or not(not(b)) = a or b

This is constructed from: 1 xor ((1 xor a) and (1 xor b)), and of course the 1 is simply a constant flowing stream of high-power water. And obviously, since NAND is a universal gate, this can be done like so:

1 xor (a and b) = a nand b
NAND can make any gate, including NOT, which is then combined as we saw above to form OR, NOR, XOR, XNOR, and even inhibitation and implication if you please.

Did that answer your question?

-jc

Re:So tell me this...

[stratjakt]

nothing, its an xor and an and gate using water instead of electricity.

you know, the type of bullshit an 8th grader would do for the science fair?

sheesh. this /. karma is getting downright embarassing. please relieve me of it, mods.

Re:Why not water?

[packeteer]

Yes i know that water doesn't conduct electricity. But most water cooling systems use water with addatives which cause them to conduct.

Re:But what about...?

[Xzzy]

> 1) how to implement other operation: OR, NOT,

well, following on the system he started you can probably get the effect of OR or NOT by altering how the "computer" reacts to the outputs, using the existing gate.

You could make an OR gate by wiring the two outputs together. Get water in either jet, and you get a 1. Put water in both jets and you get a 1. Put no water in either jet, you get a 0.

A NOT is just as simple, except you need a constant jet feeding through the gate. No water in the other jet means a 0 converts to a 1, water in both jets dumps into waste and creates a 0.

So there you have it.. by tweaking he inputs/outputs of the single existing gate you can create pretty much any conditional you desire.

GEEEZ /. users are morons!

[wirelessbuzzers]

How can people argue about this for so long!?!? If you really know nothing about chemistry, don't post about it.

Oxygen is element 8. It has 8 electrons. 6 of them are valence elecrons (in the 2s and 2p orbitals) and 2 of them are "core" electrons in the 1s orbital. Only the valence electrons get drawn in those dot diagrams, that's why you can only see six on some sites.

Hydrogen is element 1. It has 1 electron. This electron is in the 1s orbital.

Water is H2O, where the 2 is subscript. It has 2 hydrogens and one oxygen, with polar-covalent bonds between them, so there are 2*1+1*8=10 electrons. Two of them are in oxygen's 1s orbital, four of them are in two of oxygen's four sp3 hybrid orbitals, and four of them are shared between hydrogen's 1s orbital and the other two of oxygen's sp3 hybrids (one orbital and two electrons for each hydrogen).

Don't even get me started on sp3* anti-bonding pairs.

Sorry for being inconsistent as to whether numbers should be spelled out.

Re:why not use air?

[einhverfr]

Probably the first "modern"computer, the Z1 (Germany, early 30's) used aluminum moving parts (!)but because of difficulties with these sort of parts, the Z2, Z3, Z4, and Z5 used electronic relays. (Z1 was destroyed by allied bombing).

another problem

[merriam]

a not gate: an xor gate with true -- ie a constant stream -- applied to one input

an or gate: an and gate with not gates at each input and output -- or just join two streams with a simple junction

A recycling system is easily added. A more fundamental problem is that the gates are passive: there is no amplification. You can use gravity, but with feedback some lines will have to go upwards and need a complex pump for each line. Also you may need a lot of height per stage.

Fluid actuated valves would solve this problem, and would be more efficient. Only one pump would be needed -- as in electronics -- to provide the supply pressure. But in the simple case of a four-bit adder, it might be harder to make.

Re:Who else tried this?

[drDugan]

several years ago -- spring '95

a water adder capable of adding 2 8 bit values

LINK

In the Boston Science museum

[Flamesplash]

As the article states this is currently on display in the main entrance to the Boston science museum. it looks really darn cool but it just sits there, no demonstrations or anything. I think they are afraid any actual usage will break the thing. :/

Here's a better image of the contraption

Actually in Russia

[WetCat]

... water analog computers have been used since 1949... till mid 80-x for modelling differential equations.
They were used for large-scale projects, such as modelling of water dams.

Re:Actually in Russia

[Anne Thwacks]

In the London science museum they have an analog water computer that represents the British economy. I believe it predates 1949. I am not sure how accurate a model it was, but it cant be much worse that the digital model they have now.

Reseach shows the more higly qualified an economist is, the poorer his predictions!

Fluidic logic has been around for decades

[Animats]

Fluidic logic has been around since the 1960s. It's often used in industrial process control. It works for both air and liquids. Most industrial systems use air logic, but automatic transmissions often have fluidic logic running on hydraulic fluid.

The MIT students didn't quite get it right. Their gadget doesn't seem to have gain. The key insight needed for fluidics is that a jet of fluid can be diverted with a smaller jet coming in from the side. This allows building a fluidic amplifier.

Once you have an amplifier, you can do switches, gates, flip-flops, and other logic elements. Analog control systems, with fluidic sensors and amplifiers driving pneumatic or hydraulic cylinders, are also possible. When the inputs and outputs are pneumatic or hydraulic, it's often convenient if the control system is, too. Fluidic elements are very reliable, too - there are no moving parts except the working fluid.

One wierd fluidic application is this kosher public address system.

The Bay Model

[bgspence]

The Bay Model in Sausalio is a huge water based analog computer. Check it out at the army page or this VR view.

Analog fluid calculators

[haggar]

(I say "calculators" because I think that computer is underrated).

I have studied about these machines at Uni (I studied in eastern Europe): they use fluids and analog pseudo-circuits to create things like integrators, adders etc. and are capable of solving systems of differential equations in real time. This kind of equations is still a non-trivial problem for digital computers.

However, with the advent of gigabit-clocked CPUs, these machines are definitely out. Their models are, sometimes, replicated in software, though.

1936 Water Integrator photo

[Anonymous Coward]

http://www.zzz.com.ru/67.html

(scroll down for the photo)

Looks like what you'd expect of a hydraulic net that can do integral calculations.

Water Computing -- Been There, Done That

[el bid]

Hasn't anybody heard about the Phillips Machine, used for computing national economies?

The BBC has just done a radio program on Bill Phillips' invention. You can still hear it on

http://www.bbc.co.uk/radio4/science/electronicbr ai ns.shtml

--
el bid