knexcomputer.blogspot.com
The K'NEX Computer: September 2007
http://knexcomputer.blogspot.com/2007_09_01_archive.html
Mechanical Computing: Thinking with Balls. The K'NEX Calculator is now located in the Olin College library. If you are interested in a demo, feel free to visit! Posted by Jeff DeCew. Subscribe to: Posts (Atom). Built the K'NEX calculator and other logic devices while attending Olin College. It started as a final project for the Computer Architecture class and became a fun side project. The goal was to create a 4-bit programmable computer, but we settled for a calculator instead. Links to devices by others.
knexcomputer.blogspot.com
The K'NEX Computer: KNEX Calculator
http://knexcomputer.blogspot.com/2007/03/knex-calculator.html
Mechanical Computing: Thinking with Balls. The K'NEX calculator stands over 10 feet tall, and can perform 4 bit addition and subtraction operations in about 30 seconds. The slowest part of the operation is the user entering the balls. From there the balls trickle down, computing the result of the operation, and then sending that through a 4 bit decoder. Which flips a flag that tells the user the answer. Since it is 4 bit, we can add and subtract numbers from 0 to 15. Posted by Matt Donahoe. I have been t...
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The K'NEX Computer: The 4-Bit Accumulator
http://knexcomputer.blogspot.com/2007/01/knex-accumulator.html
Mechanical Computing: Thinking with Balls. This is the 4-Bit Accumulator we made at the end of last semester. An accumulator is different than an adder because it uses the result of the last operation as an input for the next operation. This one can add, subtract, and load. Posted by Matt Donahoe. January 26, 2007 at 9:57:00 PM EST. July 1, 2007 at 1:27:00 PM EST. September 7, 2007 at 3:12:00 PM EST. October 19, 2007 at 7:27:00 PM EST. Subscribe to: Post Comments (Atom). Links to devices by others.
knexcomputer.blogspot.com
The K'NEX Computer: 1-Bit Half Adder
http://knexcomputer.blogspot.com/2006/11/1-bit-half-adder.html
Mechanical Computing: Thinking with Balls. A half adder takes two, 1-bit inputs and outputs their sum as one, 2-bit value. It is made up of an AND gate and an XOR gate. Since it has the same number of inputs as outputs, it is easy to create a version using balls. We use a stated XOR to compute the digit in the one's place, and a waiting AND to compute the amount that carries over into the two's place. The A ball goes in and becomes the CARRY, while the B ball becomes the SUM. Posted by Matt Donahoe.
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The K'NEX Computer: Ball Theory
http://knexcomputer.blogspot.com/2007/01/how-it-works-part-1.html
Mechanical Computing: Thinking with Balls. Part 1: The Bit. The position of the ball determines its value. The left column is zero, the right is one, and the middle is indeterminate. Balls pass through the middle column only when they are changing state. We can get a ball to change its state by removing walls and adding ramps. This animation shows a bit being reset to zero. Part 2: The Not Gate. Part 3: The AND Gate. The animation above shows the gate in action. It has two inputs (A,B) and two output...
knexcomputer.blogspot.com
The K'NEX Computer: 2-Bit Decoder
http://knexcomputer.blogspot.com/2007/01/k-2-bit-decoder.html
Mechanical Computing: Thinking with Balls. This is a 2-bit decoder. It is used to access a desired memory location. A regular decoder takes a binary number as an input, and "activates" the corresponding bit of output. In our case, we first reset the decoder such that all output bits are active, and then as we enter the binary input, the incorrect outputs are deactivated. This was Jeff's baby. So maybe he will describe it more. Posted by Matt Donahoe. July 1, 2007 at 3:11:00 PM EST. The vertical decoder w...
knexcomputer.blogspot.com
The K'NEX Computer: November 2006
http://knexcomputer.blogspot.com/2006_11_01_archive.html
Mechanical Computing: Thinking with Balls. A full adder is comprised of 2 half adders and an OR gate. Ours is specially designed so that carry-in and carry-out are at the same height. This allows multiple full adders to be linked together. The full adder is on the right. The handsome man on the left is Jeff. This photo was taken in the Academic Center at Olin. This test shows what happens when the inputs are A=1, B=0 and Carry In=1. 1 0 1 = 10 which is a carry and no sum. Posted by Matt Donahoe. We are b...
knexcomputer.blogspot.com
The K'NEX Computer: 4-Bit Adder
http://knexcomputer.blogspot.com/2006/12/4-bit-adder.html
Mechanical Computing: Thinking with Balls. If you look closely, you can see that this 4-bit adder is 4, 1-bit full adders connected together. The carry-out of one adder drops into the carry-in of the next, moving from right to left. Since these pictures were taken, we modified the adder to be an adder-subtracter. We also added a zero flag. Posted by Matt Donahoe. Subscribe to: Post Comments (Atom). Built the K'NEX calculator and other logic devices while attending Olin College. Links to devices by others.
knexcomputer.blogspot.com
The K'NEX Computer: February 2007
http://knexcomputer.blogspot.com/2007_02_01_archive.html
Mechanical Computing: Thinking with Balls. Memory Accumulator = New Plan. We finally completed work on the 16-bits of Data Memory, and attached it to the Accumulator. The final result is a rather attractive looking tower of K'NEX. The dimensions of it are almost exactly 1' x 4' x 9' (an interesting coincidence for anyone who has read "2001: A Space Odyssey"). The project has reached an impressive milestone, and we have been showing this beast off around campus, with mostly befuddled, but positive reviews.
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