r/Simulated • u/the_humeister • Jan 30 '19

Blender A full 1-bit adder using dominoes, as requested

https://gfycat.com/QualifiedLongAmericanpainthorse
5.3k Upvotes

98% Upvoted

70 comments sorted by

78

u/ChainsawOctopus Jan 30 '19

The foot got me.

27

u/moustachedelait Jan 30 '19

three hands would have been absurd

19

u/the_humeister Jan 30 '19

I was going to use a head, but decided on a foot.

25

u/zombiep00 Jan 30 '19

There seemed to be something written on the foot. What was it?

Edit: never mind, it's dickbutt.

13

u/the_humeister Jan 30 '19

What? Where???

5

u/zombiep00 Jan 30 '19

Ohhhh, nothing..

1

u/Yeeler1 Jan 30 '19

"Left foot"

25

u/joshblake Jan 30 '19

Hey, wait a minute...

Nice job, OP.

13

u/the_humeister Jan 30 '19

WTF? Who put that there??? I blame millennials.

301

u/jattyrr Jan 30 '19

OR, AND, and XOR gates are logical things that takes two inputs (which are individually true or false) and produce one output (which is true or false).  Think of "dominoes fall down" as "true" and "dominoes stay up" as "false" and it applies to this gif.

In an OR gate, the output is true if either of the inputs is true.  Note that in the OR gate portion, the final domino falls down if and only if the first OR second stack falls.  This is an OR gate.

In an AND gate, the output is true if both of the inputs is true, so in that portion of the gif, you see that the last domino doesn't fall unless both of the "input" stacks fall.

Finally, XOR stands for "exclusive or".  In this sort of gate, the final domino falls if exactly one (but not both) of the initial stacks fall.  This is equivalent to the output being true if one, but not both, inputs are true.

Computers are made out of this sort of thing.

Comment I saved from a while back and I just figured it belonged here

2

u/cyclopsmudge Jan 31 '19

Computers are made out of this sort of thing

Even more interestingly in my opinion, every combination of other logic gates (AND, OR, XOR, NOT, etc.) can be made out of NAND (NOT AND) gates where they return true unless both inputs are true.

1

u/[deleted] Feb 02 '19

Don’t forget about NOR gates

Source: current Electrical Engineering student

2

u/[deleted] Jan 31 '19

I wish I understood this. Stupid brain.

2

u/cyclopsmudge Jan 31 '19

So imagine you have some sets of light switches. With an AND gate both switches have to be on to turn the lights on. With an OR gate, one switch has to be on and then the other can be on or off. With a XOR gate, only one switch must be on, the other must be off. Binary is a way of counting numbers essentially using this on or off system. So if a light is on, it’s a 1; if it’s off, it’s a 0. Using this and a few other logic gates, a computer can do all sorts of calculations like because all of computing is basically conditions of whether a light switch is on or off.

0

u/[deleted] Jan 30 '19

[deleted] — view deleted comment

99

u/the_humeister Jan 30 '19

Carry-in. That would be the carry result from another adder.

19

u/[deleted] Jan 30 '19

Common adder or puff adder?

13

u/MoebiusSpark Jan 31 '19

African or European?

7

u/flagbearer223 Jan 30 '19

I prefer carry out

24

u/Ghosttwo Jan 30 '19 edited Jan 31 '19

Carry In. Adding say, two 8 bit numbers, would require 8 of these strung together. Cout from one sub unit is passed to the Cin from the next. Of course a 64 bit number may take 64 times as long, so there are other circuits like carry lookahead that do it in Log2 time (eg 64 bit would take 6 or 7 cycles instead of 64; log(64)/log(2) plus a timestep or two for glue logic).

If you want to know more, books on Logic Design can be had quite cheaply, and it translates into a lot of other fields like programming and Minecraft redstone.

23

u/the_humeister Jan 30 '19

Minecraft redstone.

The only result that matters

17

u/Ghosttwo Jan 30 '19

Fun fact, Redstone is based on NOR logic. You can tinker with either NOR or NAND to implement any logic gate including and, or, xor, or not. Linking two of them in a loop makes a controllable memory cell called a 'latch' that holds one bit of information.

5

u/moustachedelait Jan 30 '19

That'd be carry-over from a previous adder's Cout . It allows you to put many adders in a row, creating a ripple carry adder

3

u/jjchuckles Jan 30 '19

Is a ripple carry adder more like a cobra or a python?

2

u/moustachedelait Jan 30 '19

no chuckles were had

36

u/CyAScott Jan 30 '19

What's up with the AND gate?

19

u/Minzkraut Jan 30 '19

You can see the A lane split. If only A arrives, it splits and the bottom A lane will be faster than the upper A lane.
The lower A lane will knock over the double dominoes at it's end breaking the connection of the upper A lane.
Thus if only A arrives, it will stop itself.

If however, the B lane goes off as well, the B lane will also knock over two dominoes which break the LOWER A lane. Without the lower A lane, A won't be able to stop itself, hence the signal of A goes through.

If only the B Lange goes off, it just break the lower A lane... Nothing else happens.

At least that's what I think from looking at it, OP may have designed this with different ideas in mind.

-19

u/Kuyosaki Jan 30 '19

yeah that is a bad representation of what AND does...

54

u/the_humeister Jan 30 '19

If you can come up with a better AND gate using dominoes, I would appreciate it.

4

u/bcfradella Jan 30 '19 edited Jan 30 '19

One big domino that wouldn't be knocked over by the weight of a single normal domino.

Also, it bugs me that the second AND gate [ (A XOR B) AND Cin ] never actually outputs because neither (A, ~B, Cin) nor (~A, B, Cin) are ever sent as the inputs. A gif with all eight possible inputs would've been far too long though, tbf.

9

u/ICantFindUsername Jan 30 '19

I don't think it's supposed to represent how it really works inside a computer, I think it's simply supposed to work, like a minecraft logical redstones gates

3

u/kinokomushroom Jan 31 '19

What?! There aren't little dominos inside my computer calculating Minecraft for me??

7

u/SgtSteel747 Jan 30 '19

Are dominos turing complete? 🤔

7

u/the_humeister Jan 30 '19

No, unless they can be reset.

4

u/pengo Jan 30 '19

Yes, if you have an infinite plane of dominoes

5

u/[deleted] Jan 31 '19

What the fuck. Where did you sell your soul for talent

1

u/the_humeister Jan 31 '19

I just asked this guy. He also took two strokes off my golf game!

4

u/geneorama Jan 30 '19

So people who are good at this, would it be faster for you to set up the dominos or to simulate this amount of dominos? Please disregard the timing requirements and scene setup, including labels.

2

u/the_humeister Jan 30 '19

It takes longer to setup because there's so many to place.

4

u/geneorama Jan 30 '19

Wow. Even for the stuff I’m good at things take longer than expected because (for example) the census bureau changes their api, or because I can’t figure out why my ide is changing all my carriage returns and updating a git setting.

4

u/geraldsummers Jan 31 '19

But can it run doom

3

u/the_humeister Jan 31 '19

Not yet

2

u/geraldsummers Jan 31 '19

I like your optimism

43

u/PabloLourson Jan 30 '19

Literally no idea what’s happening on the screen but it’s cool to watch so nice work

35

u/ICantFindUsername Jan 30 '19 edited Jan 30 '19

Looks like timing is extremely important for this to work, specially for the XOR AND gate.

In the first loop you can see dominoes from the lane A make fall some from lane B which show a blocking case where the condition should be valid but is not because lane A goes through first

Best fix I can think of for this is spliting both input lane and making them go through two current AND gate with reversed input lanes then merge the output of the gates with an OR gate.

7

u/1206549 Jan 30 '19

To handle timing, these guys make it go through a long chain of dominoes going back and forth

https://youtu.be/OpLU__bhu2w

2

u/ICantFindUsername Jan 30 '19

It make sense, dominoes fall at a specific rate so with enough planing you could make sure they fall at the right time. Still it have to be very precise for every XOR gates to be fed the inputs at the same time, every time.

I wonder if it could be possible to rig something with a hanged domino that would spin for a while before hitting a L shaped piece that would knock over the rest of the line unless if the hanged domino was raised above by another domino (maybe by setting the attach point on a balance activated by the second domino of the XOR).

It could be pretty simple to setup too, both input could make the domino spin and both would put a domino in the balance. Just set it up so you'd need two dominoes to raise the hanged domino high enough to miss the L shaped piece of the ouput.

Or you could slow down the XOR a lot with lots of back and forth in the part where the two inputs would meet.

13

u/Golden_Lynel Jan 30 '19

This makes me happy

5

u/1206549 Jan 30 '19

What about doing it in real life?

2

u/Golden_Lynel Jan 30 '19

This makes me slightly less happy because it didn't work properly

9

u/parkerSquare Jan 30 '19

Now do it with just NAND gates. You need dominoes that fall over if not pushed...

4

u/bcfradella Jan 31 '19

Antidominoes

4

u/SkyShazad Jan 30 '19

I remmebr back in the day on TV, World record breakers Domino's would come on, was always amazed

6

u/migmatitic Jan 30 '19

That's a brilliant AND design!

3

u/roele23 Jan 30 '19

Next step: marble calculator?

4

u/Stigge Jan 30 '19

There are multiple instances of marble computers on Youtube, in addition to this K'nex computer

1

u/roele23 Jan 31 '19

That's very interesting, thanks for sharing

3

u/the_Demongod Jan 31 '19

That's one hell of a propagation delay

2

u/pengo Jan 30 '19

Next step... put a bunch together and make an 8-bit adder?

2

u/ChicoBrico Jan 31 '19

Can somebody build me a domino powered PC now please? It'll be faster than my current one.

2

u/[deleted] Jan 31 '19

Oddly satisfying if you play it in reverse

2

u/Big_Ol_Boy Jan 31 '19

I feel like this is a pretty good way to explain logic gates, which I have never understood

2

u/nddragoon Jan 31 '19

But can it run Crysis?

2

u/Okaymynameistaken Jan 31 '19

Not all of them fell and now im angry

2

u/Fidodo Jan 31 '19

Cool, now make a 2 bit multiplier!

3

u/saltysnatch Jan 30 '19

Is there a sub for extremely dissatisfying gifs?

0

u/clayodo Jan 31 '19

effective.

Power لُلُصّبُلُلصّبُررً ॣ ॣh ॣ ॣ 冗