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By Jack Eisenmann

Building a TTL computer is both fun and educational! This guide will help you construct your own DUO Compact and install software. You will learn a lot about CPU architecture and digital logic. You will also gain a flexible platform for developing programs.

Why create a DUO Compact and not a modern Intel machine? Intel processors are prefabricated and execute over 400 kinds of instructions. Unless you investigate every corner of the architecture, your Intel computer will be a mysterious black box. The DUO Compact only executes 1 kind of instruction! By building a DUO Compact, you will get your hands "dirty" with low level logic. You will learn the DUO Compact architecture from the inside out. Even with a minimal instruction set, your DUO Compact will run useful programs and nifty games.

The project should cost about $160 to complete. My price estimations are below:

If you already have some electronic components, you can save money.


Please follow these steps in order. If you have any questions or problems, please contact me at esperantanaso at I should respond within a week.

  1. Understand TTL
  2. Learn the DUO Compact architecture
  3. Build and test the bare core
  4. Add peripherals
  5. Install OS and programs

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