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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:
http://twincitiespianolab.blogspot.com/2011/11/optically-routed-nor-gates-1.html
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:
http://twincitiespianolab.blogspot.com/2011/11/optically-routed-nor-gates-1.html
Parts and Tools.txt322 bytes
![How to Send Data by Light: Fiber Optics [Updated]](http://img.instructables.com/files/deriv/FRI/42MI/GU7FXUSW/FRI42MIGU7FXUSW.SQUARE.jpg)
http://youtu.be/RkpPbfy900M
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
Youtube vid here:
http://youtu.be/R2N5o67Uxf8
Ed
Here's some links to some of his computers (If you don't mind):
http://www.instructables.com/id/The-Dragon-a-desktop-computer/
(My favorite)
http://www.instructables.com/id/The-Cockworkers-Server/
(Clockworker's,for some reason the link is misnamed)
and
http://www.instructables.com/id/Buidling-a-Steampunk-mini-computer-for-the-Ladies-/
(My second favorite)
This though took me by surprise! I am looking forward to more details.