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Learning binary addition would have been more interesting if it were demonstrated using a Binary Marble Adding Machine.
Video after the jump.
“The core of the invention is a modification of the divide by two flipflop to retain the marble that falls off the right side, and keep it until the flipflop is flipped to the left by the next marble. See small diagram above right. The retention of this extra marble allows the state of the marble accumulator to be dumped. The adder would just as well add without it, but the number would have to be read off by the angle of the rockers, rather than have the device dump the count out. Really, if such an adder were integrated into a hypothetical marble computer, reading out the result as a series of marbles would be an essential element.”
Via: TechEBlog and Make
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June 28th, 2007
Very nice! Its just so simple but it works, great job!
June 28th, 2007
Oh man he’s got DRAWINGS!
June 28th, 2007
I keep trying to think of a way to make it do subtraction too.
But you probably need an extra power source to move the marbles up.
June 29th, 2007
@Henkie
To make it do subtraction you have to cut the range in half (i.e. define your range). Going from -32 (100000) to 31 (011111). This really is a matter of definition rather than math.
Then subtracting a number is adding the so called two’s complement of that number, which is inverting all bits and add one. Adding one is easy (just throw a ball in the most right column). Inverting can be done in several ways, I’m sure.
As you may or may not know, the adding one part is really setting or clearing the carry in a real processor (which is the bit that is used for extending word size). So, adding one is free in a real processor. Also, you may notice (when you try this trick on paper) that sometimes an overflow occurs. That is to say, you’ll need more digits (7) than are available on this counting machine (6). As this bit is out of range in the -32 to 31 area, it should be ignored (in reallity this again is the carry (or a borrow, depending of definition)).
June 30th, 2007
What a very effective way to show how binary works, and how binary addition is done. This would make an excellent teaching tool for teachers.
July 23rd, 2007
Dear Sir/Madam,
Hello this is Mr.Ricky Davis i will like to order some Adding machines i will like u to tell me the types u have in stocks and the price so that i can tell u the one i like and i will give u my credit card for the payment Asap.
Regards
Ricky Davis
July 23rd, 2007
Hi Ricky,
Go to the creators Web site and look at the bottom of the page for an email address.
http://woodgears.ca/