Computing with dominos (the little tiles, not the CPU architecture)

[CraigD]

So, last Thursday, the national IT organization I’m in sent me to another one of what a co-worker terms “mosh pit-style” all-day training sessions. As usual, there was little new to be learned for a veteran of a couple of decades of these sort of things like myself, except that over half of this session consisted of about 50 people playing with about 10,000 dominos!
Stay in school, kids – see what you can look forward to being paid US$70/hr to do!
With so many vets of this sort of activity, we fairly breezed though the activities intended to induce chaos and panic, and got our dominos arranged according to specs in plenty of time to discuss the fun that could be had if you had 10,000 dominos without the annoyance of packs of trainers telling you what to do with them. Being computer people, our (or at least my – a lot of the others seemed more preoccupied with what would be for lunch) minds turned to the prospect of building some sort of computer using dominos.

Under the guise of taking notes, I filled some dull time in which I was supposed to be watching a video about something with which I was already familiar sketching out the rough design of a 4-bit adding machine implemented in dominos. Yesterday, after some proof-of-design testing of some basic elements with my set of double 9 dominos (91 dominos), and a bit of googling for others thoughts on the matter, I put them through a couple of iterations of redesign, and came up with a roughly 3,000-domino, 4 x 3 meter design I think would work.

A schematic, layout of a single adder, and a schematic are attached. Note that my dominos – ordinary white plastic ones that seem to me the same size of the one I used Thursday, are 62 x 26 x 10 mm. The recommended spacing for domino chains is about 1.5 widths apart, or about 25 mm/domino.

Thinking past a binary adder in dominos, what I’d really like to do is design a layout that can do something amusing, such as play tic-tac-toe. A Turing machine of some sort – universal or not – would be fun, but I can’t imagine how to implement its tape using dominos.

Unfortunately, I doubt I’ll be able to actually implement any of these designs. Comercially manufactured dominos cost about US$0.10 each, so my 4-bit adder would cost something like $300 – more than I can justify spending for personal amusement.

So, if anyone knows how one can get their hands on large quantities of dominos, please reply. A longtime ambition of mine is to do something like this for a museum, or some sort of public event, but I currently lack connections into the world of museums and weird exhibitions.

A couple of references:
This 1999 site claims to, and until this thread at hypography, appears to be, the only site about domino computing on the internet. I owe them the idea that 2 chains of dominos can cross one another via a “pass through” junction – the domino layouts I was doing on Thursday used stairs and bridges to allow domino chains to cross, and it hadn’t occurred to me that they weren’t necessary.

There’s an annual event, ”Domino Day”, that sets up amazingly large (the current world record of over 4,000,000 domino) arrangements of dominos, then knock them down, but, as far as I can tell, their layouts are purely decorative, and don’t do any computing.

[Turtle]

Originally Posted by CraigD

Thinking past a binary adder in dominos, what I’d really like to do is design a layout that can do something amusing, such as play tic-tac-toe. A Turing machine of some sort – universal or not – would be fun, but I can’t imagine how to implement its tape using dominos.

Great idea Craig! Here's a couple links to a tinker toy tic-tac-toe playing computer; perhaps they have some ideas to borrow.
Keep us posted.


http://www.cob.sfasu.edu/sbradley/tinkertoy.html
http://www.rci.rutgers.edu/~cfs/472_...TinkerToy.html