Water Logic Gates Built at MIT
ndogg writes "This story is all wet. Paulo Blikstein at MIT has created a water computer. The one boolean logic gate he created functions as a half-adder (i.e. both XOR and AND). He then proceeded to create a four bit adder."
It's called fluidics, and it's decades old.
It uses compressed air or water to create logic circuits.
There was a big interest during the cold war, since they wouldn't be affected by the electromagnetic pulse of a nuclear bomb.
I've seen this somewhere....
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http://hardware.slashdot.org/article.pl?sid=02/10
What sig ?
...in fact, Fluidics is a very important field of study that is widely used in aerospace or mission-critical applications, where electronic control devices don't offer the reliability of cannot support the environment. Also, military technologies use Fluidics in order to prevent malfunction in a nuclear war, when electric devices cease to work.However, the idea was not to send people to space or to control missiles, but rather make a device that could help people build computation with their own hands - and demystifing the computer. I would assume that this is simply his personal write up of the project for a general audience. If it was submitted as a research project, I imagine it would be accompanied by a more thorough report which would have likely discussed the background of Fluidics with appropriate references.
New for fluidics, or for hydraulics ?
In a course on automation in the eighties, I had already seen pneumatic components and their equivalent description by Boolean concepts.
In 1995, I followed a course on automation which included pneumatics and hydraulics hands on, and the course also described certain components in Boolean terms. In fact, when I was there one of the teachers was building a pneumatic computer (never got the details on it, unfortunately).
Since the basic functions of pneumatic and hydraulic components are about the same, there is no theoretical reason why it is not possible to build a hydraulic computer.
There is one practical problem, however. Hydraulic components are mostly power components, designed to work with oil and with pressures from 10 to 100 bar, and they need a lot of space, and they are rather slow. Pneumatics is much faster and lightweight.
Yes, the main accomplishment is that it has no moving parts.
Naah. I have a copy of the 'Tomorrow's World' Annual somewhere from about 1967 showing binary log fluidic gates without moving parts. At the time, this was considered to be a possible alternative to silicon electronics for speed and compactness. People had also been anticipating MEMS technology, and saying mechanical calculators would eventually overtake electronics. Back then a transistor was still a can with three legs.
Correct me if i'm wrong but a computer cannot be created from an AND gate and an XOR gate
you are wrong, XOR together with AND is enough (neither is sufficiant on its own)
NOT A = 1 XOR A
A NAND B = NOT (A AND B)= 1 XOR (A AND B)
A NOR B = (NOT A) AND (NOT B) = (1 XOR A) AND (1 XOR B)
A OR B = NOT ((NOT A) AND (NOT B)) = 1 XOR ((1 XOR A) AND (1 XOR B))
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