Sumo Robot
April 2005
Introduction
This project was done quite some time ago. It was 2002 and I was in grade 10. I was taking the manufacturing (metal shop) class at my school and the year end project was to build a sumo bot and battle with other robots.
There was a 20lb weight limit and nothing on the bot could be 'too' dangerous, but those were the only restrictions. There were some neat designs. One guy used a toilet plunger, pop bottle and 12V tire pump and created a home-built pneumatic plunger system for pushing other bots. It wasn't particularily effective, but looked really neat. Another group went all out, spent a bunch of money on special motors and aluminum. They painted it up like an alligator. Also a really neat design. James was in that group. My group consisted of myself and Steve Melnik.
As a side note, I've been heavily involved with my high schools robotics team the past few years. Last year as an engineering team member and this year (2005) as engineering team coordinator and team leader. Check us out at www.wcirobotics.com, we're involved in the US FIRST Robotics Competition.
Continuing ... most of the other bots were just moving boxes that didn't have any special features. In the competition it was a 3-way tie for first. Our group beat plunger guy, plunger guy beat alligator bot and alligator bot beat us ... so in my mind, that makes it a 3-way tie for first.
The Game
There was a 5' x 5' playing field with a circle drawn in the centre. The matches were 1:30 long and the bot that was closest or on top of the circle at the end of the match, won. Also, to elimiate the other robot, you could push them off of the playing field all together. So there were quite a few shoving matches.
Bot
Drivetrain
| 2-wheel, direct drive. The motors were scavenged from a junk yard. They are power window motors. There's internal gearing, so they can be directly hooked up to the wheels. The motors are quite strong and have quite a bit of torque. |  |
Chasis
The chasis is made up of misc. sheet metal, folded, bent and rivitted into the general shape of a robot. After the bot was assembled with all of the motors and such, we added a large chunk of steel to the base to reach the 20lb weight limit. The heavier the bot, the harder it is for other bots to push it around.
Function
The purpose of the game was to push other bots around, as mentioned above. We wanted something 'cool' and slightly destructive on our robot, so we stuck on a spinning blade. The motor was probably out of a car as well, but I don't know which part specifically. It's fairly high speed, but has little torque. This makes it great for spinning it really fast and giving it the ability to stratch up some paint jobs really well without causing too much damage - perfect.
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Controls
| The controls are the power window controls from a car. On the electrical side, there's a common +12V wire and a common ground wire and then each switch has it's own 2 wires which are hooked up to a motor. The polarity is reversed based on whether the switch is up or down, making the bot's wheels drive forward or backwards. There was also an additional switch added to control the spinning blade function. |  |
Power
| The power is from a 12V battery, quite similar to a car battery. However, it is a fair bit smaller than a car battery and I believe it's from a riding lawn mover. |  |
Bot in Action
Here are 3 movies I've taken. I wish I had footage of the actual matches, but I don't. The movies showcase the bot's driving capability and destructive nature. 2 of the movies show it tearing apart an apple and the third shows it driving around and then catching a cloth on the spinning blade.
After making the videos, the floor was covered in apple mush. Not fun to clean up.
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Conclusion
I did this project as part of a tech class in
2002 when I was in grade 10. It wasn't the most
difficult of projects, but me and Steve had a
lot of fun doing it. I've included it on the website
just to show something from 'the early days' and
to show that you can have a lot of fun if you
grab the motors and switches out of a car 
.