A Turing Machine Built With Lego, And a Place To Put It 74
New submitter Otis_INF writes "To honor Alan Turing, two researchers at the CWI built a simple LEGO Turing Machine, to show everyone how simple a computer actually is. Primary goals were to make every operation as visible as possible and to make it using just a single LEGO MINDSTORMS NXT set."
And if a simple Turing machine gets old, Reader miller60 adds a link to this Lego data center "that recreates all the major features of an IT facility, assembled from 5,772 pieces, 28 figures, and 1 meter of fiber optic cable. The builder, Tanaka, has uploaded details to the Lego Digital Designer Gallery so others can build and adapt their own."
Turing machine emulation using physical memory (Score:5, Informative)
As has been (kinda harshly) hashed out on hackernews, this is really a turing machine emulated on a NXT using lego as a physical memory display. This is still cool, but its not "turing machine built out of lego" except by the extreme interpretation that a NXT computer is sold by the lego corporation.
There have been some genuine mechanical turing machines built with varying level of success.
Its pretty easy to make an electromechanical relay based turing machine if for no reason other than price (well, price compared to when I was a kid, its still gonna be a chunk of change)
When I was a teenage kid a simple DPDT 12 volt relay at radio shack cost me something like two HOURS of labor income, and now as a "highly" paid jack(-ass) of all computational trades I can buy a simple DPDT from Mouser for something like two MINUTES of labor income. I've got a bitslice ALU design (admittedly not a turing machine) down to about 22 relays per bit. Latching relays are about 50% more money than non-latching. Also QPDT relays are "cheap" and commercially available.
large PCBs are expensive. Yet sockets and hand wiring is not cheap either (although it looks cool)
I'm stuck on (electro-)mechanical memory storage devices. There was a single bit core memory design from a 1970s electronics magazine that used simple steel washers as cores, terrible magnetic properties but cheaply and widely available. However I don't want an electronic design. Latching relays are cheap enough for registers and ... surprisingly enough ... latches ... but they're a bit expensive for main memory. For example an Altair size of memory made of latching relays would cost me about 256 bytes * 8 bits * 3 bucks per latching relay equals $6.1K just for storage not to mention decode logic. Until I can figure out a way to get below $1/bit purely electromechanically I think I'm stuck.
The history of computation, since the 1940s (before even my time) has always been "computation is cheap, memory is expensive"
That has been done before (Score:5, Informative)
Re:It's an LBA, not a TM (Score:4, Informative)
Look, I may be an annoying aspie too here, but the project isn't cool because it uses a fucking computer to simulate a computer.
"Therefore, to avoid limiting the instruction size and to protect the running program, we chose to write the instructions to a file on the NXT brick and uses the simplest interpreter to run these instructions."
so the point is just to be a pointless cool looking device. it's not implemented in lego.