Carol's LEGO Difference Engine 2. (click for larger image)
Posted on 02/09/2006 6:26:12 PM PST by zeugma
Before the day of computers and pocket calculators all mathematics was done by hand. Great effort was expended to compose trigonometric and logarithmic tables for navigation, scientific investigation, and engineering purposes.
In the mid-19th century, people began to design machines to automate this error prone process. Many machines of various designs were eventually built. The most famous of these machines is the Babbage Difference Engine.
Because of engineering issues as well as political and personal conflict the Babbage Difference engines construction had to wait until 1991 when the Science Museum in London decided to build the Babbage Difference Engine No.2 for an exhibit on the history of computers.
Babbage's design could evaluate 7th order polynomials to 31 digits of accuracy. I set out to build a working Difference Engine using LEGO parts which could compute 2nd or 3rd order polynomials to 3 or 4 digits.
There is a lot more coming to this page over the next few weeks.
More details on how it works, and more pictures. Including pictures of the engine broken into its basic adder units as well as close ups of the important mechanisms.
Do you want to contact me about the machine?
I am available at: aecarol@coastside.net ..and... aecarol@woz.org
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I can also tie this into current events if you squint just a little bit at it. You see, Lego is a product of Denmark. Given the issues that the country is currently having with whacked out muslims, (is there any other kind?), I figure Lego is tangentially topical.
That tie-in is a major stretch, since it is 'Mentos Cool'(TM), we're good to go. :-)
Very cool- thanks for the post.
BTW mechanical computers didn't die out with Babbage. Every office in the US had mechanical adding machines not very many years ago- they could add, subtract and multiply.
The main guns on the Iowa class battleships are directed by mechanical ballistic computers.
WWII US subs had mechanical fire control computers linked to the periscopes and on-deck binoculars through a Torpedo Bearing Transmitter (TBT) system. Compute the enemy's course and speed, Triangulate their position, enter the sub's course and speed, turn the crank, and it plots the bearing and range for the torpedo shot. Pretty nifty, eh?
You must not live with siblings. Younger, rug cruising, siblings destroy Lego creations because it's fun; older siblings destroy Lego creations to see if they can upset you, and, because it's fun. How do you propose to keep the difference engine in one piece, because you know, friends destroy Lego creations because... it's fun.
Moms destroy your Lego creations because the floor is filthy & she need to clean.
(That's where most of mine went, anyway. :-)
You need this, cleans and sorts!
ROFL!
Now THAT is a useful invention!
I saw an article about a museum attempting to actually build an 'Analytical Engine' about a year or so ago. They were attempting to machine the thing out of the same material Babbage would have used. It turns out that it was not as easy as one would think even using modern machine tools because the tolerances had to be so tight. That's one reason I thought the Lego version was so cool.
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"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?'
I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
Charles Babbage (1791-1871)
Sounds like politicians haven't changed in ages.
It was electro-mechanical. Yeah, platinum is better, but it normally sells at a 15-20% premium to gold, and gold has the advantage that it doesn't corrode. It was a nice bit of hardware. Once we upgraded to more modern hardware, I recovered the gold with a bit of teenage elbow grease. :-)
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