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chris

The Turbo Entabulator - a 3D-printable, fully mechanical computer

by chris Jun 9, 2013
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"A master piece of engineering, i hope more comes from this maker."

-A random bunny found in a hole

But can it play DOOM???

I'm learning Java, so as a project, I decided to make an emulator of this "computer".
(As of this writing), it isn't complete, but it should be sometime soon.
As the "emulator" supports many 'memory banks', the punchcard system uses a boolean array as follows:
counter1 increment, counter1 decrement, counter1 check 0, counter2 increment, counter2 decrement, counter2 check 0... and so on and so forth.
If anyone is interested, it can be found here: https://github.com/dmelcer9/MechanicalComputerEmulator

I built a larger electromechanical version with the same basic architecture called the 'Numbotron': http://www.chrisfenton.com/the-numbotron/ - my website has a link to a simulator so you can play around with it. That one has 8 x 3-digit registers, and a drum that can hold 20 instructions. The main difference between the two, architecturally, is that the Numbotron will skip instructions if the 'check if zero' condition is true at the start of the instruction, whereas the turbo entabulator will still inc/dec all of the selected registers once if that's true. I haven't thought about how to do that entirely mechanically yet, but it lets you do branch predication, which enables much more complex programs for it (like finding prime numbers!). Check it out!

Great idea. Was anyone able to put it into work?

cool - but what does it do?

But, does it reduce sinusoidal deplenaration?

I had an operation for that but when they pull the plug out of your nose it's a killer !

"An Excellent Computer."

-Chef Excellence

Thank you Chef Excellence for this review.

I am very new in learning how to position pieces so that they come off of the table without a crowbar and so that clean up is clean (not too many little stubbies from scaffolding).
I noticed that you place thin things so that they print vertically. Is that the way you printed them? I have found that when I do that (not on your stuff but others) it starts to wobble at the top and does not finish well - especially round things with a small foot print.
do you have some tips on when to do it vertically and when to lay flat. Also figuring out when to raft and when to scaffold.
Thanks - your computer things look great - can't wait to print them.

I pretty much always print long/thin things with the longest dimension on the platform. I have a Thing-o-Matic which has a moving platform, rather than a moving extruder, so very tall/thin parts printed vertically rarely work.

I too am a newby at 3D printing but I think I can help your problem. Typical for me is to print a fine pyramid with a misshapen blob at the tip. If you have a fan use more cooling so tall prints are stiffer at the top. If you can't do that, try printing 2 or 3 at once so each can cool while the print head travels between them.

Very cool. I think it would be nice if you gave us an explanation of what exactly was going on in the video though.

No problem! With each revolution of the hand-crank, a little punch card on the 'cylinder' (the rectangular box that has the 4 punch cards draped over it) selects a set of hooks that get lifted up. Each hook is tied to a string, so that when the hook gets lifted up, the string gets pulled on. Each one of the three counters has two strings connected to it. Pulling on one string increments the counter, pulling on the other string decrements it (if you tried to pull both at the same time, it would just jam up!).

The 'cylinder' gets rotated 90 degrees, so that the next 'instruction' punch-card selects the hooks, when the little hooked lever-arm behind it is raised up. Each of the counters also has a little indent on its surface, so that when it reads '0', a spring-loaded lever gets raised up (three additional hooks are used to optionally force these levers downward, so that the state of the counter will get ignored), which rotates a shaft that ultimately raises the lever-arm that advances the cylinder - Voila! The machine executes an 'instruction' that looks something like this: "Increment or Decrement this set of counters until one of the counters reaches zero"

The four instruction cards on the cylinder form a little program that computes the fibonacci sequence, a number sequence where the next number is formed by adding the two previous numbers (1,1,2,3,5,8,13,21,34,etc.). In the video, I pre-load the machine so that the first two counters each read '1', and the last counter reads '0'. As I turn the crank, the counters get incremented or decremented until the result gets deposited in the right-most counter (and I left a spare hook to ring a little bell when the next result was done, but sadly, I couldn't find a suitable bell in time).

The video is of my computing the fibonacci sequence up to '8' on the right-most counter. I was really excited at the end, since I think it took me about 5 tries to get it to run without something jamming up or skipping. It was too hard to turn the crank and explain what was going on at the same time, and I was using a laptop webcam to film it, so it wasn't easy to move it around a lot. The pictures really give a better view of how the machine works.

What are the specifications for the cards?
My CAD software was giving me a bunch of issues with trying to measure position and size of the holes, and wouldn't give a round number.
Thanks

The instruction holes are on 0.3" centers, and 0.5" tall x 0.2" wide. The cards are 1.8"x3.3"x.1" thick. The centering holes at the top and bottom are centered in the middle of the cards, but the hole centers are offset 0.25" from each edge (the holes themselves are 0.25" diameter).

Here is the link:
http://www.thingiverse.com/thing:661438
Thingiverse messed up the project, but instructions are in the description.

Customizable Punchcard

Thanks- I am also trying to learn openscad, so that will be a nice challenge.
I'll post the thingiverse link when(if) I'm done.

Congrats at being featured here and on leapfrog 3d printers.

Congrats on being Featured, I knew you had it in you!

How many gigahertz? :D

That's really awesome!!

My reaction: WOooOOAAAA!

Holy smoke, you guys are just in time to produce an analogue chesscomputer to celebrate it's a 100 years ago that the chesscomputer made its debute!
It could mate king+rook versus king at a tinier board from a specific startposition against any legal counterplay.
See http://en.wikipedia.org/wiki/El_Ajedrecistahttp://en.wikipedia.org/wiki/E...

You nutter! Love it!

Uber-mega-points for the name. I mean, it's totally awesome, and appropriate as well, so that name takes it right over the top. Well done sir!

I should make this as a ode, to my days working at Babbages before it got turned into gamestop ;)

Holy Crap! This is amazing!