My (hopefully) epic school project!

[MelvinS4_]

So, I thought this project of mine would interest you guys.

Here in Sweden, when we enter the last year of high school we have to make a project in order to prove that we are ready to graduate and move on to higher studies. As my project I've decided to make a mechanical computer. That's right, no electricity whatsoever.

More specifically, due to not being allowed to simply build the computer as my project, the project will be about using a mechanical computer as a visual tool for studying computer science.

I'd like to hear your thoughts about this. Do think I'll manage to make it and what to think of it as a tool in order to study computers? When/if I succeed with this I'll make sure to post pictures and a description.

Btw, does anyone happen to know if it has been done before? I've not been able to find any information about a fully mechanical computer actually being built. I know that the British mathematician Charles Babbage made sketches of what he called "The Analytical engine" but it was never finished. (This was also the inspiration of this project in the first place).

[Apuly]

https://www.youtube.com/watch?v=s1i-dnAH9Y4
There are a bunch of them on youtube. Just searching for 'mechanical computer' gives you a whole bunch of results.
As for making the computer itself, I would be very impressed if you pull it off.

[MelvinS4_]

https://www.youtube.com/watch?v=s1i-dnAH9Y4
There are a bunch of them on youtube. Just searching for 'mechanical computer' gives you a whole bunch of results.
As for making the computer itself, I would be very impressed if you pull it off.

While that most certainly is a computer, it is not what I meant. The definition of computer I'm using in this project is a digital, programmable and turing complete computer. It will have a working memory, ALU and so on.

[Nuuppanaani]

Awesome project Melvin!
I'm truely interested on seeing how this comes together.

btw. Prepare for the criticism from piston haters xD

[Legofreak]

Awesome!

If it is supposed to be digital, what kind of movement will define 1 and 0?

I started making logic gates in Space Engineers and was able to make pushrods represent 1 and 0.
I have an example of an XOR on the steam workshop which is made up of NOT and OR gates. NOT is just a lever that goes to the other side and OR has 2 arms that push a lever but cant pull it.
http://steamcommunity.com/sharedfiles/fi...=301359118

I've seen other ways of doing them too. I hope you succeed!

[MelvinS4_]

If it is supposed to be digital, what kind of movement will define 1 and 0?

With digital I simply meant that the data will not be analouge, but rather an exact value. The computer will likely use a high base, perhaps 60 or more.

The program memory might however use binary, since I'm thinking of using punched cards. Not decided on that yet..

[Nickster258]

I used legos. Simple, motor to turn on. Counter-clockwise = 0 Clockwise = 1.

[MelvinS4_]

I used legos. Simple, motor to turn on. Counter-clockwise = 0 Clockwise = 1.

So you've built one? A little more detail would be appreciated. Pictures?

[Nickster258]

I used legos. Simple, motor to turn on. Counter-clockwise = 0 Clockwise = 1.

So you've built one? A little more detail would be appreciated. Pictures?

It was a little while back and I did not take pictures. I simply used a combination of motors and differential gears to achieve it. It was a binary adder and I really could not do much else. I'll see what I can find online.

Edit: This was the closest thing I could find. It uses a simple lever system

[MelvinS4_]

I used legos. Simple, motor to turn on. Counter-clockwise = 0 Clockwise = 1.

So you've built one? A little more detail would be appreciated. Pictures?

It was a little while back and I did not take pictures. I simply used a combination of motors and differential gears to achieve it. It was a binary adder and I really could not do much else. I'll see what I can find online.

Edit: This was the closest thing I could find. It uses a simple lever system

Too bad you didn't take pictures, always interesting to see what solutions different people have come up with. The "ALU" in my computer will very likely be a Charles Babbage styled adder/subtractor. See this for an idea on how it works. I might include a multiplier and sin/cos, not decided on that yet.

[Tjakka5]

I have some experience with building a mechanical computer, so if you need any help you can ask me anytime.

Some things to think about though:
1. What are you going to use to build it? Lego? Knex? Metal? Wood?(!)
2. What are you going to use to do the logic? Gears? Balls? Pins being pushed/pulled?
3. Keep in mind that you'll probably need tons of motors because of friction.
4. How much will it cost? Will you be able to pay for it?

[MelvinS4_]

I have some experience with building a mechanical computer, so if you need any help you can ask me anytime.

Some things to think about though:
1. What are you going to use to build it? Lego? Knex? Metal? Wood?(!)
2. What are you going to use to do the logic? Gears? Balls? Pins being pushed/pulled?
3. Keep in mind that you'll probably need tons of motors because of friction.
4. How much will it cost? Will you be able to pay for it?

Thanks for wanting to help out! I'll be using gears for logic. As for building material, I really only have two choices: wood or plastic. If I could I'd rather make it out of Lego or Meccano, but that stuff's crazy expensive! When it comes to cost, my school has got me covered atleast with a thousand SEK (~140 USD). It's not a lot, but I think I'll manage if I put some money in myself.

[Tjakka5]

Sounds pretty good, altough as I said, you're going to need lots of motors for that.
You see, there's going to be tons of stuff moving (atleast 3 gears for a xor gate) so there's going to be huge amounts of friction too!

Building it out of wood sounds like a great plan! That is, if you know how to work with it :p

I was wondering.. Can I add you on skype? We could brainstorm together a little bit on how you (and I) would create such a thing. Maybe even collaborate a little bit.

[MelvinS4_]

Sounds pretty good, altough as I said, you're going to need lots of motors for that.
You see, there's going to be tons of stuff moving (atleast 3 gears for a xor gate) so there's going to be huge amounts of friction too!

Building it out of wood sounds like a great plan! That is, if you know how to work with it :p

I was wondering.. Can I add you on skype? We could brainstorm together a little bit on how you (and I) would create such a thing. Maybe even collaborate a little bit.

Though I won't make anything that even slightly resembles a xor The machine will not contain a single logic component the way I've planned it. Ofc there will be lots of moving parts but I'll try to combat that by only having one piece of it operate at a time (if the whole thing was to operate simultaeniously it would also require pipelining, something I've never gotten the hang of ).

The biggest problem I'm having right now is how to "mass produce" the gears. I will need a large amount of them and don't feel like making them all by hand ideas?

As for Skype, I'm not quite comfortable talking over the interwebs but I have no problem with discussing here on the forum (via pm) or by mail.

[Legofreak]

find somebody with a CNC router. you can cut as many gears as you want out of cheap material.

If you are able to use 3d modelling simulation software, that would probably help... lol

[Tjakka5]

How are you going to represent data then?

My idea was the following:
Turning = 1, not Turning = 0.
Direction doesn't matter, thus you are able to use some mechanical tricks to make logic gates (or, not, xor, and)

The way I can see you do it is with turn speed (torque), which could definatly work, but would be very interesting to see happen. Especially the registers would be a challenge.

[MelvinS4_]

Data will be represented as the angle of the cog. This way a cog could theoretically store any number since the choice of base becomes arbitrary. Power is not needed for memory, since the cogs (unless written or read from) are always stationary; the amount of moving parts at a time therefore is not that great.

[Tjakka5]

Sounds pretty good, although, with that you wont be able to use bitwise logic, which may or may not be useful. Dividing and multiplying will also be a bit tricky.

[Legofreak]

https://www.youtube.com/watch?v=loI1Kwed8Pk
awesome explaination video of a handheld mechanical calculator

[MelvinS4_]

https://www.youtube.com/watch?v=loI1Kwed8Pk
awesome explaination video of a handheld mechanical calculator

That's actually the mechanism that I'm planning to use for the "ALU". No need to reinvent the wheel, right?

[PhysoniumI]

Base 10 ALUs FTW, right?

How would you manage logic? :3

[MelvinS4_]

Base 10 ALUs FTW, right?

How would you manage logic? :3

Don't think I'll implement any logic actually. It is not needed for most calculations so there's no real need that I can see. Branching will be implemented with zero checking and maybe carry overflow flags.

[Tjakka5]

who needs logic anyways amiright?

[PhysoniumI]

It's not a real cpu/alu without logic

[MelvinS4_]

It's not a real cpu/alu without logic

What? There is no need for logic in an alu at all.

[Tjakka5]

Arthimetic(?) LOGIC unit.
But yeah, you don't need it, although you might want some sort of greater than/lesser than flag somehow somewhere.

[MelvinS4_]

Arthimetic(?) LOGIC unit.
But yeah, you don't need it, although you might want some sort of greater than/lesser than flag somehow somewhere.

Well, suppose I'll just call it the AU then I will have a comparation (correct english?) flag, however I've never considered this to be a part of the logic. Maybe I got my terminologly wrong? Logic for me is only the logical operators on memory and the bitwise stuffs.

On an unrelated note, some help with an IS would be appreciated. I am very bad at designing these so it would help me out alot. I'm thinking of a simple RISC system with 4-8 registers, add/subtract and right/left shifting. Branching will be both conditional and unconditional, with conditions being carry overflow and equal/less than zero. Any thoughts?