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[DPRG] Mini Sumo and the popular Vacuum/Magnet issue

Subject: [DPRG] Mini Sumo and the popular Vacuum/Magnet issue
From: Pete Miles petem at ormondllc.com
Date: Fri Nov 1 15:33:00 CST 2002

This is probably one of the most contested issues in amature robotics I have
seen in the last 5 years.

Let me make this point clear, I am NOT telling anyone to change their rules
to allow magnets and vacuum in mini sumo.

I personally believe that mini sumo is the best place for beginners
(regardless of age and sex) to get started in robotics.  They are easy to
build, and don't cost a lot of money.  The mini sumo Dohyo is small and easy
to build and carry around so everyone can have their own ring at home.

I go to a lot of robotics events, and non robotics events, including local
school science fairs, and promote mini sumo.  None of the mini sumos I
present have vacuum, magnets, sticky wheels.  I show off the Mark III at the
events, and now that I have a SumoBot from Parallax, it will be shown at the
next science fair I am going to.

I have no intentions of changing this, because I want this to be a place
where people can get excited about robotics.

My discussions about magnets and vacuums are usually more generic and not
specifically targeted to Mini Sumo, but since this is what everyone wants to
relate it to, then lets talk about it.

When it comes to technology advancements as it relates to mini sumo, what
are people talking about these days?

Casting wheels.  That is right, making sticky wheels to give their robot a
competitive advantage over other robots.  This was once frowned on, but it
is now accepted, at most events.  There are lots of discussions on how to
cast silicon and polyurethane wheels, at several robotics clubs.  People put
on presentations on how to do this at meetings, and people are detailing how
to do this on their websites.  The only reason why people want to spend the
money for the polyurethane (which is expensive) is to give them a
competitive advantage.  I would not be surprised to see a company selling
polyurethane wheels within one year.

It is funny how people hated this idea a couple years ago, and it is now the
rage in mini sumo.

Where are the other technological advancements in mini sumo?  Sensors?
You can buy an ultrasonic range sensor for $30 for Acroname and Lynxmotion.
Hey they are great devices, they work very well.  Buy three and you have
some really good coverage for your robot (270 degrees of coverage).  But
that is almost $100 added to the price of the robot.  Nobody complains about

You can buy the Sharp G2PDxx range sensors for your robot, average, $15 each
>from Acroname.  They have a really narrow field of view, so you will need
say 5 of them to have a similar view coverage from the ultrasonic sensors.
Thats about $75.  Nobody complains about someone spending that much money on
their robot.

Lasers?  Ken Maxon has to perfect laser ranger I have ever seen for this
application.  Needs to be made smaller, but would not only tell you how far
your opponent is, but the exact location.  It is the perfect sensor for sumo
robots.  We are talking hundreds of dollars here.  Nobody will complain
about someone using this system.  This type of system is needed for the
robotics community, and it is too complicated for most of us to figure out.

Better sensors means you can use better programming logic to attack your
opponent.  Most mini sumo robots appear to move more in a random motion than
immediately finding their opponent and attacking them.

One thing is for sure is that better sensors makes robots more expensive.

In the end, the goal of a mini sumo robot is to push the other robot out of
the ring.  The ability of a robot to push the opponent out of the Dohyo is
based on the apperent weight of the robot and the coefficient of friction of
the wheels.  The whole polyurethane custom casting wheel efforts going on
across the country is focused on the wheel friction.

Magnets and vacuum address the weight issue.

But lets talk about magnets first.  If the Dohyo is not made out of steel
(or other magnetic material), then having magnets on the robot is not an
issue since won't do anything but add weight.

Since most mini sumo robot builders add lead weights to their robots, why
not add magnets to increase the overall mass to 500 grams.

Rear earth magnets are easy to get and are cheap when you go to surplus
houses like Electric Goldmine.  Implementing a magnet on a robot is
relatively easy to do, and doesn't cost a lot of money.  Much cheaper to do
than adding any ultrasonic sensors, and hand full of the Sharp G2PDxx

A simple such as a SumoBot with a couple magnets will be able to compete
much better against top notch robots such as Goliath and Nemisis where they
can not add magnets because their general design makes them heavy.  Adding a
couple magnets does allow beginners to compete against some of these old
time veterans.  Right now, no commercial mini sumo can compete at the same
level as Goliath and Nemisis.

Now lets talk about vacuum.

First, it is highly unlikely that someone will build a robot with a vacuum
system in a mini sumo.  But someone might, and it will be a really
innovative design.  I do have a 1 inch cube vacuum pump I got from Gast
Manufacturing for $50.  I am hoping to make a vacuum mini sumo with it.  It
is more of an experiment just to see if I can do it.  One thing is for sure,
the crowd will be very impressed to see a vacuum robot compete on a glass
window.  You can almost make a contest with a sheet of glass held
vertically, and the sumo compete on the glass.  You will have literally 360
degree viewing of the contest.

If you allow magnets, you might as well add vacuum

Vacuum on a 20 cm square sumo is easy a lot easier than people think.  A
good vacuum pump from Medo costs only $60.  And most of the Japanese use teh
same pump you can get in the U.S.  Vacuum cups are easy to build.   I built
a pretty good vacuum system in one evening using Sintra plastic, rubber
cement, some foam rubber, and a coping saw.  It sticks to the wall quite

I don't think cost should be an argument that it is only for those people
who have a lot of money.  Anyone willing to buy a couple ultrasonic sensors
can afford a vacuum pump to make a sumo robot.  And magnets are a lot

But these are just some arguments for allowing magnets and vacuum.

If you are a purest, and do not want to allow and traction enhancing devices
such as sticky wheels, magnets, and vacuum systems, in your events, then
that is fine with me.  I am not telling you that you have to have them.

Mini Sumo is a great contest, and I like it the way it is.  But I also like
to see things evolve so that the same two robots that win every year have to
change in order to keep winning.  Current mini sumo rules favor the Goliath
and Nemisis designs.  Allowing magnets and vacuum should make things much
more interesting.

Like I said before, I am not telling you to change your rules.  I just
presented some arguments for allowing them.

petem at ormondllc.com

----- Original Message -----
>From: "David P. Anderson" <dpa at io.isem.smu.edu>
To: <dprglist at dprg.org>
Sent: Friday, November 01, 2002 12:38 AM
Subject: [DPRG] Micro Robots: A modest proposal

> Howdy
> Pete Miles posted some good, interesting comments about robot sumo and
> contests in general.  Pete is the event co-coordinator for the Seattle
> (they do a great job at their yearly Robothon, I can tell you from
> experience) so he has obviously thought about this a great deal: sticky
> tires and magnets and audience building and rules issues.
> He makes some very interesting points about robot contests and their
> motivations, to wit:
> > When the crowd loves an event, the event grows because they get involved
in it.
> >
> > If the crowd doesn't like the event, it becomes boring, and eventually
> > because the competitors go away from it.
> <snip>
> > ask yourself this question. Why are you even
> > competing in it?  Is it because you enjoy the technical challenge of
> > building a sumo robot, or do you like to hear the crowd cheer you on.
> > there was not one spectator to watch the event, would you still compete?
> >
> > When you hold a public event, do you do it for the spectators or the
> > competitors.  If it is only for the competitors, then why make it a
> > event?
> Why indeed?
> Some might argue that Pete is confusing the advancement of hobby robotics
> the entertainment industry, but they would miss the larger issue.  I spent
> years myself as a musician and professional entertainer, so I believe I
> speak with some experience and candor on this subject.
> I would therefore like to propose three additional elements for our robot
> contests, and for all our robot contests in general, which I believe are
in the
> spirit of Pete's observations and which I believe would be logical and
> valuable add-ons to the competitions.  Perhaps even the BattleBots folks,
> who I understand were not picked up for a 6th season by the Comedy
> might benefit from these suggestions.
> I propose we can enormously increase audience interest and excitement in
> robotic events by the addition of these three elements:
> 1.  Gambling
> Wagering on the outcome of robot sumo is a natural, and will
> up the revenues of robot clubs substantially, bringing in a
> whole new heretofore untapped audience for our events, as
> well as providing healthy purses for the winners and thereby
> increasing both the size and level of competition.  For clubs
> in states where gambling is illegal, I propose video links
> to casinos in areas where wagering is allowed.  We might even
> consider a special "Native-American" sumo class for the gambling
> establishments on the reservations in neighboring states.  This
> simple addition will, I believe, totally change the face of the
> hobby of robotics and in a single stroke make it a legitimate sport.
> 2.  Alcohol
> This more than any other element will increase the excitement
> as well as the volume level of the crowd, and is another potential
> source of income.  Take a cue from professional sports here,
> BattleBot aficionados!  People like to drink at sporting events,
> especially if they also get to gamble.
> 3. Scantily Clad Large-Breasted Women.
> Once again, the experience of professional sports like WWF wrestling
> suggests that huge cheering crowds as well as almost certain television
> coverage and the accompanying fame and revenues which will follow can
> bring our fringe hobby out of the shadowy halls of weird science and
> into the mainstream.  I'll be there for sure!
> Think of it, folks.  Visual-Basic Joe with a fist full of dollars and a
babe under each
> arm, stoned out of his mind and screaming for YOUR ROBOT!  It just doesn't
get any bigger
> or more exciting than that.
> Now if you are offended by these admittedly vulgar suggestions, you might
perhaps console
> yourself with the thought that the huge sums of money raised from these
events will go
> a long way toward paying for whatever clever serious robot inventions you
may be nurturing
> in your quiet little workshop.  Think about it.
> most respectfully,
> dpa
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