Steampunk Electro-Optical Logic Machine




About: Wide range of interests supported by my day at Nonin Medical.
Could a digital computer have been built prior to 1900?  Babbage's Difference Engine shows one possibility of a mechanical computer but what about an electrical approach.  The Steampunk Electro-Optical Logic Machine uses photoconductors and gas discharge tubes which were both in use by 1880 to form a NOR gate logic array.  The principles of Boolean logic were also available by this time to assist in the systematic design of such a device.  The routing of light through total internal reflection had also been demonstrated.  

Although the specific materials and methods used here would not have been available by 1900 this device is interesting as a way to visualize how  the basic logic gates; AND, OR, XOR, XNOR, Set/Reset Latch and D Latch can be formed by connecting NOR gates.  This breadboard also can be "routed" while it is powered up.  Results are immediately visible without having to use an oscilloscope or voltage meter.

A word of caution this circuit is powered by 110VAC.  Observe all pertinent safety precautions when building, testing and using the circuit.  

Videos of the circuits can be seen here:

More background info available here:



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    13 Discussions


    7 years ago on Introduction

    Even if you only get as far as a few basic computing elements, I think you may have won steampunk computing.

    2 replies

    Reply 7 years ago on Introduction

    Thanks! I will be posting a the routing for a very simple vending machine stae machine in a couple of days.


    6 years ago on Introduction

    A computer could have definately been built before the 1900s. All the components of the first computer existed and were in use at least a hundred years prior to whenthe first computer was actually built.


    7 years ago on Introduction

    And furthermore this video shows real time rocking flipping and flopping between Q and Q/ by routing Q/ back to D input. This is the basis of counting and this circuit is now able to count to 1 and back to 0. Not too shabby.

    If you do watch the video give this a thought. This family of logic gates is unique (as far as I know. . . OK SEED* but can YOU make one at home?) in that it does these three things:

    1. Accepts input from user
    2. Computation of input data
    3. Outputs result of computation to user

    all with the same logic device. In fact it is almost "transparent computing" in that what ever it is that is going on, you can see it. You might go a little crazy trying to keep track of what you are seeing of course but nonetheless, nothing is hidden.

    SEED = Self Excited Electro-Optical Device


    And now it can do "sequential stuff ." Thanks much to you and P2PU for getting me back into the research thing.

    Youtube vid here:



    7 years ago on Introduction

    A little delay in detailing construction plans and circuit applications I'm sorry to say. On the plus side I am working on a series of articles for Electronic Engineering Times ( on the subjects of Steampunk, electro-optical circuits and the history of computing. Will follow up with links and more info soon.

    That is neat! On a side note, love the pictures of the Steampunk Tardis, that one of his friend was working on...

    Speaking of computers, have you seen some of user, Horatius.Steam's computers? He got some neat computer case mods... true they're not as pure Steampunk tech as yours is, as they are modern computers.....
    Here's some links to some of his computers (If you don't mind):
    (My favorite)
    (Clockworker's,for some reason the link is misnamed)
    (My second favorite)

    Evidently I have been influenced by Richard Nagy's (Datamancer's) work, more than I realized. Cause at first I thought this was a scanner inside of a book, like his....
    This though took me by surprise! I am looking forward to more details.

    1 reply