THE LV TANKER

"IN THIS CORNER, WEIGHING IN AT 1.982 KILOGRAMS … THE LV TANKER!!!"

Sumo Bot Entry for 7th Grade NYS Science Olympiad by JP

This Sumo Bot runs on low voltage batteries and uses a programmable Arduino microcontroller for all controls. A second Arduino communicating via 2.4 GHz XBee is used for remote control. The remote talks I2C to a Wii nunchuck joystick with accelerometer. The Tankers high-torque motors and locking transmissions, plus double sided operation with automatic attitude detection make it a tough challenger. It was designed to meet the NYS Science Olympiad Class "B" specifications.

 
The LV Tanker Top-side View

Tanker bottom-side view with major features

Bottom-side view showing lightening holes, homemade remote control, and initial design in Blender

Starting with a design in Blender nearly 11 months ago the LV Tanker took estimated 250 hours to build, 3 prototypes, 4 motor shield designs, and many hours of programming.

Features 

• 2 high torque low voltage motors with orbital gear transmissions in a tank-style configuration
• On-board ATMEL ATmega328 microprocessor in Arduino Duemilanove configuration with 32Kb memory and 16Mhz clock speed
• 2.4 Gigahertz wireless mesh network communications based on the XBee
• Laser assisted guidance
• Multiple programmable modes
• Automatic attitude detection for seamless two sided operation (it can be flipped over and still drive and nunchuck automatically reverses)
• Rugged aluminum, steel, & plastic construction
• 9 individually controlled LED status indicators
• Piezoelectric "speaker" for audio signals
• Symmetrically balanced motors with locked stopped position by Black & Decker
• Direct driveshaft for main axels, light-weight Nylon chain driven secondary axels for tank-like operation
• Transistors with electrically isolated left and right channel motor relays
• Operation with Wii nunchuck joystick and accelerometer control or old-school 2.4 GHz wireless Arduino based joystick

Special thanks to:

• Arduino - http://www.arduino.cc/
• Adafruit - for their parts and tutorials
• Tod Kurt - for his instruction and inspiration
• Gold Coast Hobby for motivation
• Dr. Wolf, Mr. Lee and Mr. Maier for their sponsorship  

http://sports4nerds.blogspot.com/

http://sports4nerds.wordpress.com/

Feel free to contact us for more information, code etc.

Specs:

• Locust Valley Tanker
• L: 30cm, W: 29.5 cm, H: 7.5 cm
• 1.982kg (U.S. PO Weight)
• (4) 1.5V "AA" and (4) 1.5V "C"
• By JP

Parts, software and help from Arduino, Mouser, Black & Decker, ThingM, Adafruit, Digi, ATMEL, TI Sparkfun, Fun Gizmos, Radio Shack, Duracell, ST, Seeed Studio and others.

H-Bridge Motor Controller

After burning out the H-Bridge motor controller from Adafruit we tried the NYT version and had the same problem. We have started a new design based on the design by Radu Motisan at http://www.pocketmagic.net/. We have laid it out in Eagle and built it on a breadboard and its working well so far. We are trying to add forward and reverse LEDs before we move it over to a Radio Shack 276-150 board. If you need the parts list available from Mouser let us know.

C# "Software Joystick"

We've hacked together a C# program that writes motor commands like #+20-15; (motor 1 200 forward, motor 2 150 reverse). The serial port has Xbee connected to it. The only tricky part was the motor equations below.

double radians = Math.Atan2(dy, dx);radians = radians + Math.PI / 2;

m1 = (int)(Math.Abs(dx) * Math.Sin(radians) + Math.Abs(dy) * Math.Cos(radians));

m2 = (int)(Math.Abs(dy) * Math.Cos(radians) - Math.Abs(dx) * Math.Sin(radians));

(Equations from David "Wild Shot")

(ps: Its a Visual Studio 2005 project - We can post a copy once its been cleaned up.)