5 ms·

I Built a Mechanical Calculator [video]

127 points by lispybanana 2y ago

bnkd_ 2y ago
Great work !
whyage 2y ago
Great work, excellent video.
tombert 2y ago
I love thinking about the "what if?" universe where we never figured out semiconductors and transistors, but still had roughly the same level of human progress. Would everything be clockwork like Syberia [1]? Would we have something akin to iPhones but done entirely with electro-mechanical stuff with antennas? I guess this is sort of the appeal of something like Steampunk. Mechanical calculators are ridiculously cool to me. If I ever become an eccentric billionaire, I really want to buy an original Curta calculator [2], just because I respect the genius and engineering required to design such a thing. The one in this video is also very cool. Very satisfying to watch all the gears turn at once. [1] https://en.wikipedia.org/wiki/Syberia https://en.wikipedia.org/wiki/Syberia [2] https://en.wikipedia.org/wiki/Curta https://en.wikipedia.org/wiki/Curta
- sebzim4500 2y ago
  You don't have to be a billionaire, I got a Curta mark I for ~£850 on ebay and it's like the world's greatest fidget toy.
  - tombert 2y ago
    £850 is actually cheaper than I thought it was, but it's still a bit much for me to justify right now. If I spent a grand on a fidget toy, I think my wife would be pretty mad at me. Whatever patents that they had have to be expired, I kind of wish someone would make reproductions. I know there's the 3D printed ones, which are cool in their own right, but since 3D printers aren't super precise the parts have to be huge to compensate. I want as close to a one-to-one reproduction as possible, but I guess there's not much money in it.
    - MatthiasWandel 2y ago
      I'm sure they would not have been less than £850 in whatever currency it was sold in back then, inflation adjusted. But the justification was much better than being a fidget toy.
      - tombert 2y ago
        Oh definitely, prior to having cheap computers that can compute gigaflops, I would definitely have bought one to do number crunching. The problem is that if I bought one now, it would simply be a toy and nothing else. That's just a bit more than I'm willing to spend.
        econ 2y ago
        Update it with USB so that it can take input and return results. Hook it up to a cash register for something like an antique store. Ideally one selling small items so that the customer can marvel at the display adding things up.
        tombert 2y ago
        I also have always wanted one of those mechanical vintage cash registers, for the same reason I have always wanted a Curta. They always seemed like they would be fun to play with. I could probably get one of those cash registers to play with for not a ton of money, but my house isn't huge and it's hard to justify the space.
    - ddulaney 2y ago
      It doesn’t help that they made an absolute ton of them: something like 140,000! That means that they’re not particularly rare, and it holds the price down. Add in the fact that authenticity is part of the appeal, plus the fairly expensive process to make a decent replica, it’s not shocking that no replicas have emerged, even though cheap-ish CNCs mean it’s probably easier to do than it ever has been.
- fooker 2y ago
  Maybe without semiconductors we would stumble upon something better sooner. Maybe optical/biological/quantum computing.
renlo 2y ago
Great video, I really enjoyed how down to earth it was. It reminded me of The Secret Life of Machines [1], where we get to peek behind the curtain and see how seemingly "magical" machines (in your case a digital computer) emerges from simple fundamental concepts. [1] https://en.wikipedia.org/wiki/The_Secret_Life_of_Machines https://en.wikipedia.org/wiki/The_Secret_Life_of_Machines
theendisney 2y ago
You can just continue the division by inputting the remainer i think?
rtkwe 2y ago
I don't know if he mentioned, the name doesn't show up in the transcript, it but this seems to be very close to an unrolled Curta, the main difference being that it doesn't use 9s complement for subtraction so it has a more complex bidirectional carry mechanism. Otherwise the function is very similar down to shifting the turns and output accumulator to multiply the entry number. The big drum he makes many of is just one in the Curta that actuates every output dial through a full rotation. 9s complement makes subtraction extremely satisfying on the Curta because it causes a carry on (almost) every single output and turn accumulator dial.
- matt-attack 2y ago
  Yep. The whole time I kept thinking, “oh so that’s why I have to that to the curta” or “oh so now I get what’s happening in my curta!”
- WilliamG52 2y ago
  Hi, I made the calculator and this video. As I discuss throughout and particularly towards the end of the video, my design is based on Thomas de Colmar's Arithmometer (~1820-1860) and Leibniz's Stepped Reckoner (late 1600s), both of which predate the Curta (1930s). Or rather, the Curta is a super cool and elegant refinement of those (and other) designs. I think it is more accurate to say the Curta is like a rolled up version of those (and my) calculator. The "big drum" you mention is sometimes called a Leibniz Wheel, though this naming convention is misleading in some ways: http://journals.cambridge.org/abstract_S0007087414000429 http://journals.cambridge.org/abstract_S0007087414000429. As that article argues (though I disagree with some points), the history of calculating machines is more nuanced than a linear progress narrative suggests. So, I tried to keep my narrative a little tighter and not go much into the calculators of the late 19th century and the designs in the 20th century like the Curta. Also, the Curta's (awesome!) story has been told many times, so I did not feel the need to go into it. Sorry to go on this long, but I think this history is fascinating and how we tell it speaks to how we understand how technology changes through time.
  - gregschlom 2y ago
    Just wanted to say, fantastic work and video. I really enjoyed watching it.
orbital-decay 2y ago
What is the simplest way to do mechanical logic? Without all those fancy looking gears. I wonder how far it can go if you actually optimize it.
- tocs3 2y ago
  I have had an interest in building a mechanical computer for a long time. It has not ever gotten farther that some research into what route to take. There are lots and lots of simple logic mechanisms (many, many in use in real world applications). It can go as far and be as capable as you have time for.
- jecel 2y ago
  An interesting option is rod logic, which is the mechanical equivalent to a PLA (programmable logic array). https://www.jamiekawabatarobotics.com/?p=40 https://www.jamiekawabatarobotics.com/?p=40
- pgarza00001 2y ago
  https://www.youtube.com/watch?v=G_SC7oWL78A https://www.youtube.com/watch?v=G_SC7oWL78A The Whiffletree was used in mechanical calculators. It's an interesting way to encode digital data mechanically.
drcode 2y ago
the madness of cutting hundreds of gears by hand, many with a 45 degree bevel, I couldn't even imagine. madness!
simonjgreen 2y ago
For a second video, this is amazing. It also took me to their first video which is a mechanical hand, also out of wood https://youtu.be/gxT8TfI5DaE https://youtu.be/gxT8TfI5DaE
lo_zamoyski 2y ago
Mechanical computers are a great reminder of what computation is and what it isn't. Computation as studied by computer science is not a physical phenomenon, but a mathematical construct that claims to formalize the notion of an effective method. This claim is perhaps most tangibly expressed in the form of the Church-Turing thesis. Computing devices are not objectively computing. They simulate the formal construct. Anything that can be used "computer-wise" can be said to be a computer in the same manner that anything that can be used chair-wise can be said to be a chair. But there is nothing inherently computational about the device itself.
- Joker_vD 2y ago
  > Computing devices are not objectively computing. They simulate the formal construct. Isn't it backwards? I don't think that e.g. herding sheep into the pen while making a mark on the door for each sheep "simulates counting sheep". Instead, you can use the formal construct "counting sheep" to describe this physical process: "doing this and this will count the sheep". Otherwise you may very easily end up puzzled why maths is so unreasonably effective in natural sciences.
deleted 2y ago
[deleted]

127 points by lispybanana 2y ago

bnkd_ 2y ago

Great work !

whyage 2y ago

Great work, excellent video.

tombert 2y ago

I love thinking about the "what if?" universe where we never figured out semiconductors and transistors, but still had roughly the same level of human progress. Would everything be clockwork like Syberia [1]? Would we have something akin to iPhones but done entirely with electro-mechanical stuff with antennas? I guess this is sort of the appeal of something like Steampunk. Mechanical calculators are ridiculously cool to me. If I ever become an eccentric billionaire, I really want to buy an original Curta calculator [2], just because I respect the genius and engineering required to design such a thing. The one in this video is also very cool. Very satisfying to watch all the gears turn at once. [1] https://en.wikipedia.org/wiki/Syberia https://en.wikipedia.org/wiki/Syberia [2] https://en.wikipedia.org/wiki/Curta https://en.wikipedia.org/wiki/Curta

sebzim4500 2y ago
You don't have to be a billionaire, I got a Curta mark I for ~£850 on ebay and it's like the world's greatest fidget toy.
- tombert 2y ago
  £850 is actually cheaper than I thought it was, but it's still a bit much for me to justify right now. If I spent a grand on a fidget toy, I think my wife would be pretty mad at me. Whatever patents that they had have to be expired, I kind of wish someone would make reproductions. I know there's the 3D printed ones, which are cool in their own right, but since 3D printers aren't super precise the parts have to be huge to compensate. I want as close to a one-to-one reproduction as possible, but I guess there's not much money in it.
  - MatthiasWandel 2y ago
    I'm sure they would not have been less than £850 in whatever currency it was sold in back then, inflation adjusted. But the justification was much better than being a fidget toy.
    - tombert 2y ago
      Oh definitely, prior to having cheap computers that can compute gigaflops, I would definitely have bought one to do number crunching. The problem is that if I bought one now, it would simply be a toy and nothing else. That's just a bit more than I'm willing to spend.
      - econ 2y ago
        Update it with USB so that it can take input and return results. Hook it up to a cash register for something like an antique store. Ideally one selling small items so that the customer can marvel at the display adding things up.
        tombert 2y ago
        I also have always wanted one of those mechanical vintage cash registers, for the same reason I have always wanted a Curta. They always seemed like they would be fun to play with. I could probably get one of those cash registers to play with for not a ton of money, but my house isn't huge and it's hard to justify the space.
  - ddulaney 2y ago
    It doesn’t help that they made an absolute ton of them: something like 140,000! That means that they’re not particularly rare, and it holds the price down. Add in the fact that authenticity is part of the appeal, plus the fairly expensive process to make a decent replica, it’s not shocking that no replicas have emerged, even though cheap-ish CNCs mean it’s probably easier to do than it ever has been.
fooker 2y ago
Maybe without semiconductors we would stumble upon something better sooner. Maybe optical/biological/quantum computing.

renlo 2y ago

Great video, I really enjoyed how down to earth it was. It reminded me of The Secret Life of Machines [1], where we get to peek behind the curtain and see how seemingly "magical" machines (in your case a digital computer) emerges from simple fundamental concepts. [1] https://en.wikipedia.org/wiki/The_Secret_Life_of_Machines https://en.wikipedia.org/wiki/The_Secret_Life_of_Machines

theendisney 2y ago

You can just continue the division by inputting the remainer i think?

rtkwe 2y ago

I don't know if he mentioned, the name doesn't show up in the transcript, it but this seems to be very close to an unrolled Curta, the main difference being that it doesn't use 9s complement for subtraction so it has a more complex bidirectional carry mechanism. Otherwise the function is very similar down to shifting the turns and output accumulator to multiply the entry number. The big drum he makes many of is just one in the Curta that actuates every output dial through a full rotation. 9s complement makes subtraction extremely satisfying on the Curta because it causes a carry on (almost) every single output and turn accumulator dial.

matt-attack 2y ago
Yep. The whole time I kept thinking, “oh so that’s why I have to that to the curta” or “oh so now I get what’s happening in my curta!”
WilliamG52 2y ago
Hi, I made the calculator and this video. As I discuss throughout and particularly towards the end of the video, my design is based on Thomas de Colmar's Arithmometer (~1820-1860) and Leibniz's Stepped Reckoner (late 1600s), both of which predate the Curta (1930s). Or rather, the Curta is a super cool and elegant refinement of those (and other) designs. I think it is more accurate to say the Curta is like a rolled up version of those (and my) calculator. The "big drum" you mention is sometimes called a Leibniz Wheel, though this naming convention is misleading in some ways: http://journals.cambridge.org/abstract_S0007087414000429 http://journals.cambridge.org/abstract_S0007087414000429. As that article argues (though I disagree with some points), the history of calculating machines is more nuanced than a linear progress narrative suggests. So, I tried to keep my narrative a little tighter and not go much into the calculators of the late 19th century and the designs in the 20th century like the Curta. Also, the Curta's (awesome!) story has been told many times, so I did not feel the need to go into it. Sorry to go on this long, but I think this history is fascinating and how we tell it speaks to how we understand how technology changes through time.
- gregschlom 2y ago
  Just wanted to say, fantastic work and video. I really enjoyed watching it.

orbital-decay 2y ago

What is the simplest way to do mechanical logic? Without all those fancy looking gears. I wonder how far it can go if you actually optimize it.

tocs3 2y ago
I have had an interest in building a mechanical computer for a long time. It has not ever gotten farther that some research into what route to take. There are lots and lots of simple logic mechanisms (many, many in use in real world applications). It can go as far and be as capable as you have time for.
jecel 2y ago
An interesting option is rod logic, which is the mechanical equivalent to a PLA (programmable logic array). https://www.jamiekawabatarobotics.com/?p=40 https://www.jamiekawabatarobotics.com/?p=40
pgarza00001 2y ago
https://www.youtube.com/watch?v=G_SC7oWL78A https://www.youtube.com/watch?v=G_SC7oWL78A The Whiffletree was used in mechanical calculators. It's an interesting way to encode digital data mechanically.

drcode 2y ago

the madness of cutting hundreds of gears by hand, many with a 45 degree bevel, I couldn't even imagine. madness!

simonjgreen 2y ago

For a second video, this is amazing. It also took me to their first video which is a mechanical hand, also out of wood https://youtu.be/gxT8TfI5DaE https://youtu.be/gxT8TfI5DaE

lo_zamoyski 2y ago

Mechanical computers are a great reminder of what computation is and what it isn't. Computation as studied by computer science is not a physical phenomenon, but a mathematical construct that claims to formalize the notion of an effective method. This claim is perhaps most tangibly expressed in the form of the Church-Turing thesis. Computing devices are not objectively computing. They simulate the formal construct. Anything that can be used "computer-wise" can be said to be a computer in the same manner that anything that can be used chair-wise can be said to be a chair. But there is nothing inherently computational about the device itself.

Joker_vD 2y ago
> Computing devices are not objectively computing. They simulate the formal construct. Isn't it backwards? I don't think that e.g. herding sheep into the pen while making a mark on the door for each sheep "simulates counting sheep". Instead, you can use the formal construct "counting sheep" to describe this physical process: "doing this and this will count the sheep". Otherwise you may very easily end up puzzled why maths is so unreasonably effective in natural sciences.

deleted 2y ago

[deleted]