Homebrew TTL logic computer

Although [Jack] just graduated High School and doesn’t have much experience with electronics, that didn’t stop him from building the DUO Adept, a homebrew computer built entirely out of TTL logic chips.

The DUO Adept has 64k of memory, 6K of which is dedicated to the video ram that outputs a 240×208 black and white image onto a TV. Bootstrapping the computer to it’s current state was quite a challenge, as an entire OS was put into th system one bit at a time though DIP switches. After the OS was written to the computer, [Jack] was able to connect a keyboard and started programming. [Jack] programmed a hex editor and a few games of his own design. If all that wasn’t impressive enough, [Jack] also programmed an assembly compiler and emulator for his homebrew system.

We’ve seen a a few homebrew computersbefore, but not many of them are laid out on 17 breadboards like the DUO Adept. With skills like these, we can’t wait to see what [Jack] comes up with next. Check out the video after the break for a walk-through of the build.


  1. Dear Jack:

    You’re epic.

  2. a.d says:

    OK, that’s impressive. Just a shame that breadboard is such a mess.

  3. blarghmaster says:

    hmmmm… wireporn

    all and all… that is mighty impressive

    I do wonder though how well it could be expanded? like say for example adding more memory or a form of networking? image a few crates such as this all farmed together…

    i say again… hmm… wireporn :P

  4. Dave says:

    I’m having some trouble resolving these two sentence fragments: “doesn’t have much experience with electronics” and “a homebrew computer built entirely out of TTL logic chips”

    He damn sure does now. Nice work Jack.

  5. EllisGL says:

    I’ve actually been watching this project for a while, just wished there were real schematics.

  6. fartface says:

    “Bootstrapping the computer to it’s current state was quite a challenge, as an entire OS was put into th system one bit at a time though DIP switches.”

    Wah? Many of us did that in the early years. load with the toggle switches the code that allows us to use the hex keypad to go hella faster.

    Want to try difficult? using dip switches and a push-button to HAND LOAD a eprom for the initial bootload…

    Load, press write, now press read to make sure what was loaded was correct, continue… you make ONE mistake and it’s start over from the beginning and grab a new chip.

  7. fartface says:

    One thing I find fishy, no photos of the board except through the tub to make sure you cant read chip numbers or see how things are wired….


  8. HHH says:

    That guy is great.

    The only thing that could stop him is…..a girlfriend :-P

  9. Andy Goth says:

    For a fun time, copy the contents of http://web.mac.com/teisenmann/iWeb/adeptpage/DUO_OS.txt into the first entry box of http://web.mac.com/teisenmann/iWeb/adeptpage/adept_compiler.html , then click Compile followed by Execute.

  10. Aaron says:

    fartface: Did you miss the “Interior View” link on the photo gallery page? Granted you still can’t read the markings on the chips, but that’s largely because there are seven thousand jumper wires in the way.

  11. Peter says:

    That’s awfully impressive. I read through the description on his website. Nice job. I hope Jack’s considering a career in engineering.

  12. jeff-o says:

    EPIC work here. There’s a bright future ahead for this guy.

  13. Chris says:

    Impractical. Crazy. Like many things here.

    Except this one is just impressive as hell.

    Jack is awesome. If he can do this with TTL and breadboards, imagine what he’ll be able to do with more advanced stuff like FPGA’s…

    @Fartface: Check out the “View Video Demonstrations” link on Jack’s page, there’s plenty of good wireporn shots.

  14. cdilla says:

    Jack, that’s one great piece of work. Pulling together the design, hardware and software skills like that is very impressive indeed.

  15. EFH says:

    Mad props to Jack

  16. Mr Foo says:

    Should’ve used an Arduino.

    Oh, hang on. Wrong comment.

    Wow. Mad, mad, mad stuff. Quite possibly one of the bestest things ever.

  17. Cpt. Obvious says:

    Impressive. Fap level impressive.

  18. svofski says:

    E P I C

  19. MrX says:

    This is indeed impressive.

  20. Miroslav says:

    Impressive. Great video as well… There appear to be few 40 pin chips with 0.6 in. width as well? Microprocessors? :)

  21. CMJ says:

    Miroslav, I’m guessing some type of VRAM

  22. IJ Dee-Vo says:

    n0ob pwning epicness!

  23. lwatcdr says:

    Someone send that young man a wire wrap tool now! Really holly cow batman that is dang impressive just imagine what he will do after college.

  24. Chad says:

    Now for a bootstrap ROM and SD card wiring…

  25. ColinB says:

    Jack, it would be an understatement to say you are incredibly talented. That is an impressive system and you must have had a lot of perseverance to get it working! The JavaScript compiler/emulator is really cool too.


  26. abobymouse says:

    I hope fpga companies send him a bunch of stuff.

  27. Steve says:

    Wow! That is some awesome stuff. And that is one truly giant mess of wiring spanning those breadboards. Excellent job!

  28. Eugene says:

    He is obviously on a mission to understand computers from the ground up. If you look at the other projects he has done a 2 bit relay computer, 4 bit ttl computer and now an 8 bit ttl computer. Very old school. The only thing missing is a vacumn tube computer, but I would not put that in a plastic tub!

  29. Jag says:

    Awesome !. You must be very proud of yourself !!!

  30. JB says:

    Amazing! I like seeing young people interested in technology. I hope he follows up with a college education.

  31. my mind says says:

    This guy has an incredible patience!
    anyway probably with an Arduino would have been better, or in some ways easier…

    very impressive…

  32. Fili says:

    I’d add something like a punch-card reader. Some phototranzistors read black/white dots from a sheet of paper that was printed before and transform it into code. A lot faster than DIP switches and less error-prone.

  33. anfegori91 says:

    This boy is a genius, watch it solving a 4x4x4 rubik cube:

  34. anfegori91 says:

    Note: He is the computer creator :)

  35. Joe says:

    This guy is probably the next Steve Jobs / Bill Gates.

  36. Fred says:
  37. QU3RY says:

    Seriously epic…

  38. Andy Goth says:

    Did anyone else notice the reverse bit order convention? He puts the least-significant bit on the left. For example, here’s 0 through 7: 0000 1000 0100 1100 0010 1010 0110 1110. I guess that’s valid, just a little unusual. Probably much easier to program. I heard a rumor that Alan Turing did the same thing, at least in decimal, such that “51” is fifteen.

  39. bobdole says:

    Andy Goth: Not that unusual. It’s a perfectly cromulent way of addressing, called little endian. http://en.wikipedia.org/wiki/Endianness#Byte_addresses_increasing_from_right_to_left

  40. Jack A18 says:

    Jack you are a legend!

  41. Elias says:

    This. Is. Fucking. Epic.

  42. iHME says:

    That is one impressive build.

  43. Opwernby says:

    @Andy Goth: if you’re using an 8-bit chip, it can make things much easier because then you always know that the lsb of your operand is the first byte; also, with x86-type chips (16-bit and above) the operands are arranged this way anyway, with the lsb first.

    Fantastic achievement, by the way, this thing.

  44. bc says:

    Tremendously well done Jack, this is just the tenacity and grass-roots effort our next generation of developers will need, so refreshing so brilliant, Jack please continue to reach for the stars…

  45. Tweeks says:

    Glad to see that I’m not the only one who breadboards using the rats-nest method.. :)


  46. bigdumbdinosaur says:

    What’s an “assembly compiler?” I’ve been working with computers for years and never met one of those. I know what an assembler is and what a compiler is. But an “assembly compiler?” Is that what results when the Commodore MADS package mates with Aztec C?

  47. michael says:

    that’s good stuff just thinking if os2 can be installed in it

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