Constructing a Maze

So, you want to build
your own maze. Well, you have to really want to. Many people have built
full or partial mazes. A competition quality maze is going to be time-consuming
and/or costly to produce. Remember that the finished article would be 3m
square – I would have to remove all of the furniture in my living
room if I wanted to put one in there. Imagine how well that idea would go
down.

If you have the facilities, you can make one from 12mm fibreboard. It is called MDF in the UK and probably nowhere else.
One of the benefits of MDF is that it leaves a very good surface which
will need little or no preparation for painting. Chipboard needs the edges
filling. You may be able to trust your timber merchant to slice a sheet
up into suitable strips.

there is definately some 12mm laminated white chipboard (particle board) available somewhere. haven’t found a supplier yet. I will put the name of a source here if I find one.

Use a jig to cut the walls to length (168mm).
There should be no holes in the maze floor so the best way to join walls
to posts is with a tongue on the wall and a slot on the post. The post
will need fixing into a hole on the base. Since there should be a post
at every lattice point you will need to drill a lot of holes accurately
in the base. Use a jig for this as well.

A full size maze will measure 2.9m square (nearly ten feet). This is
irritatingly just a bit too big to be made conveniently out of standard
(in the UK) 8′ x 4′ sheets. Can anyone tell me why they chose such an
arbitrary size? The original maze specifications had cells 7″ wide.
Another oddity. Why not 6 inches?

How big should I make it?
As a competitor, you may not have access to a full size maze and you are
probably unlikely to have enough room for one anyway. Try building a couple
of sections that you can put together in different ways. I have seen at
least one mouse that could not cope with a full 15 cell run as it had
never run over a distance greater than a quarter of the maze. Many builders
manage an 8×8 practice maze. Even that will require about 5 foot square,
similar to the space taken up by a typical double bed. Similarly, your
searching algorithm had better not have any hidden bugs brought on by
not expecting a full-size maze.

Accuracy
Notice that the rules give some fairly specific guidance relating to tolerances
and imperfections in the maze. Try and ensure that you can cope with worse
than those given. While you are searching and travelling relatively slowly
this should not be too hard. The problems accumulate very quickly at speed.

Since the rules generally state that every lattice point must have at
least one wall attached to it, you can build a maze using 180mm walls
with a peg at one end with slot to make an integrated post. The other
end will just have a tongue. An alternative is to just put pins on the
lower edge of the walls and drill four holes at each lattice point.

The real bad news is that you are going to want to make 300-400 walls
for a full sized maze. A single 8×4 sheet of material may yield nearly
100 walls. If you can cut these carefully enough, paint the sheets first,
then cut them. This is a simple but tedious job. For my practice area,
I used planed softwood. This measured up at 12mm x 47mm. The loss of height
was no big deal because I use side-looking sensors. However, this material
is far from stable and my walls are now all curved in one or more directions.
I like to tell myself that, if my mouse can cope with these, it can cope
with anything. Of course, I also like to tell myself that I will win on
the lottery.

[As it turned out, when placed in a ‘proper’ maze, my mouse was delightfully
smooth as it no longer had to try and follow the variations in paint colour
on my low-grade walls. While I had the right idea, I had spent ages trying
to get a smooth response to poor workmanship.]

Painting
Ensure that the paint you use holds no nasty surprises. Some black paints
can be good IR reflectors and some white paints will absorb IR. Don’t
imagine that, just because the wall tops are red, that they are good IR
reflectors. Remember that the maze you compete it is likely to have very
different properties.

If you really want to get a feel for a competition run, make sure you
have some very bright lights to simulate the lighting conditions of the
competition. Oh, and try to have a number of autofocus cameras firing
IR at your mouse as well 🙂