This project will start off by describing the basics of electronics. After that, the fundamentals of binary and boolean logic will be described. Lastly we will then move onto the function of the various parts of a simple-as-possible computer (with a few modifications) as described in Malvino's text Digital Computer Electronics. This means that the end product of this Instructable will be a computer that you can program with a unique instruction set. This project also leaves many of the design aspects of the computer up to you and serves as a guide for building your own computer. This is because there are many ways to approach this project. If you already have a sound understanding of boolean logic and the workings of binary feel free to skip to the meat of the project. I hope that you all enjoy and get something out of a build like this, I know that I sure did.
For this project you will need:
1.) A power supply
2.) Breadboards + lots of wires
3.) LED's for output
4.) Various logic IC's (discussed later)
5.) Free time
6.) A willingness to mess up and learn from mistakes
7.) A lot of patience
Optional (but very useful):
2.) Digital multimeter
3.) EEPROM programmer
4.) Sonic screwdriver
Useful Links for a Project Like This:
Digital Computer Electronics: http://www.amazon.com/Digital-computer-electronics-Albert-Malvino/dp/007039861
TTL Cookbook: http://www.amazon.com/TTL-Cookbook-Understanding-Transistor-Transistor-Integrated/dp/B0049UUV38
Step 1: What Is a Computer?
What is a Turing Machine? A Turing Machine consists of 4 parts: the tape, head, table and state register. To visualize the operation of such a machine you first have to imagine a film strip spanning infinitely in each direction. Now imagine that each cell of this film strip can contain only one of a defined set of symbols (like an alphabet). For this example let us imagine that each cell can only contain either a "0" or a"1". These cells can be rewritten an infinite amount of time but retain their information indefinitely until they are changed again. The part of the Turing Machine known as the head can write symbols to the cells as well as either increment or decrement its position on the film strip by a given integer (whole number) of cells. The next part is the table which holds a given set of instructions for the head to execute such as "move right 4 cells" and "set cell to 1". The fourth and final part of a Turing Machine is its state register whose purpose is to hold the current state of the machine. The state includes the instruction as well as the current data on the tape.
That is how simple the operation of a computer is. When your computer operates, it is actually operating as a turing machine. It processes data held on your computer by a given set of instructions and algorithms. The computer described in this Instructable is a very simplistic model of a computer, but it still operates as one that you can program with a set of instructions that it will follow and execute.
Wikipedia on Turing Machines: http://en.wikipedia.org/wiki/Turing_machine