Homebrew Turing Machine

Mike Davey, a maker from Wisconsin, built a classic Turing Machine with a 1000 foot instruction tape that holds up to 10k. Though Turing's machine was just a thought experiment, the paper in which it is described has enough detail to create it in real life. The machining is absolutely lovely, and when it's in motion, it's a thing of beauty.

A Turing Machine (Mike Davey)

DIY Turing Machine (IEEE Spectrum))

(Thanks, Erico!)



  1. Would be awesome if it used a wider variety of symbols, say Mandarin, and pronounced them when it read them.

  2. What do the 10 k’s do? You’d think you’d need more of the other letters — k isn’t very common, in English at least, so you’d expect the machine to be loaded up with e’s or a’s or t’s instead. Weird.

  3. I desperately want to break into this guy’s house while he’s away and write a blocky, machine-like “2” at the end of whatever tape he’s got loaded into it.

  4. This is awesome. I can’t believe how polished the whole project is. I could easily see this thing churning away on a pedestal in a museum. Excellent work Mr. Davey!

  5. Weren’t turing machines supposed to also store their program on tape?

    Putting it on SD card seems like taking a short cut.

    Would have been faster to use magnetic tape instead of the optical one. ;)

  6. I feel really weird saying this, but… it was oddly beautiful seeing it write out those nice, perfect ones and zeroes.

    That tickled some sort of really neurotic pleasure center in my brain.

  7. As a BS in CS I would like to argue that the Turing machine is not simply a ‘thought experiment’ but a _revolutionary_ model in computing theory. In my Finite Automata and Grammars class (the hardest class I ever took) it was proven to me that if you can build a Turing machine on paper to solve a problem, then it is therefore mechanically or electronically computable.

    1. Thought experiments can still be revolutionary, just ask Einstein. Relativity started as a series of thought experiments.

  8. That is just awesomely cool.

    Here is this extremely sophisticated, industrialized *realization* of a Turing machine actually emulating (with absurd precision) the theoretical idea that inspired it in the first place. Isn’t that irony delicious?

    And that playfulness extends out to the maker who created it. He obviously delighted in the painstaking work he took, just like the machine he built could be said to “delight” in painstakingly performing this simple, abstract computation. A computation that harnesses resources inside the machine’s controller chip that of course vastly exceed its own complexity.

    Far out!

  9. Two papers were written on the computability of numbers. One was by Turning and the other by Alonzo Church. Turning came to the U.S. to study with Church at Princeton.
    When he was back in England working on a more efficient way to decode the Enigma machine, electronic were pretty primitive. He needed a delay line to do a logical operation with an earlier result. It was an acoustic delay line and used a mixture of alcohol and water in a glass tube. The preferred liquid was gin right out of the bottle.

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