At the Dutch Cube Day a few
years ago a couple of chaps had brought along a pair of robots capable of
solving a standard 3*3*3 Rubik’s Cube. So, coming from two different countries
they did the obvious thing and held an international robotic Rubik’s Cube
solving competition as a fun interlude to the serious speed-cubing competition under-way. I can’t remember who won, but remember seeing the robots in action
and while they certainly weren’t flawless, seeing a robot built entirely of
standard Lego kit accept a scrambled Rubik’s Cube, read it and then set about
actually solving it, successfully, was pretty awesome.
Now I’ve never been much of a
twisty puzzle fan – sure I have a bunch of them in the collection – well, you
kind of have to, don’t you? But they don’t exactly get exercised much … knowing
that I was going to get visited by some serious twisty-nuts in the near future,
I got to wondering about those Lego Rubik’s solving robots and did some
Googling.
I discovered not only the
version I’d seen in Eindhoven a few years back, but also a newer design that
seemed a bit more robust based on a newer Lego Mindstorms kit… so I did a bit
more surfing (or research) and watched some more YouTube videos and showed some
of them to Gill, who thought they looked pretty cool… so a couple of days later
I duly ordered a Lego kit from Amazon along with some rechargeable batteries
and downloaded the instructions from David Gilday’s incredibly useful website.
A couple of happy hours spent
building the structure spread over a few evenings took me right back to my
childhood when I used to play with my mate’s Lego Technic stuff. A little time
spent downloading a patch to the Lego software (to improve the colour
recognition on the cubies) and then loading up the solving software onto the
Lego brain brick.
Turn it all on and run the
program and it jiggles around a bit while the various arms reset their home
positions. When it settles down, scramble a 3*3*3 cube and place it on the
turntable. The infrared sensor notices your hand and deduces there’s probably a
cube to play with and the contraption springs into action – reading the colours
on each side while the arm on the left flips the cube in between sides.
Once it’s read all the sides it
has a wee think before the turntable and the arm spring into action in a flurry
of twisting and turning - until it announces with a bit of a fanfare that the
cube is solved and it proudly shows off all the sides perfectly solved.
It must have a pretty decent
algorithm for solving the cube since it seems to take an average of around 24
moves to solve them … it won’t try solving an already solved cube and if you
give it a cube with a pattern on it, it seems to neatly undo the moves you’ve
used to put the pattern there in the first place.
It was a terrific little project
and a great diversion from serious puzzling and I now have a fun little talking
point to share with my twisty friends when they visit.
[If you’re interested in
building one of your own, David’s site has variants for the different versions
of Lego Mindstorms kits out there, the building instructions are simple enough
for an old kid to follow with virtually no previous experience and he explains
exactly how to get all the software and patches loaded and running… and he runs
a FaceBook page where you can ask questions if you run into trouble – in short it’s
a great resource and David’s done all the hard work for you – but you get to do
all the fun stuff.]
