1. SEI Robotics Lego Mindstorm Competition

2. The Team Kelli Boehringer Scott Bourgeois Dennis Underwood
Brannon Veal

3. Objective
To navigate a robot autonomously through a house (pictured at right), find a candle located randomly in one of the four rooms, and extinguish it

4. Budget Lego Mindstorms NXT kit - $249.99
Mindstorms Ultrasonic Sensor - $31.99
Miscellaneous Items (brought from home)
Mardi Gras Cups $0.00
Flour $2.00
Baking Soda $1.00
Duct Tape $4.00
Napkin $0.00
Cling wrap $3.00
Total Purchased $281.98
Total Budget $291.98

5. Concept and Design: Axles
Three designs
Three wheels (Mindstorm’s Tribot design)
Four wheels
Two wheels + Skid

6. Axles: Three Wheels Benefits Problems Turned easily Moved fast
Accurate turns hard
Could not support much weight
Could not go over stairs

7. Axles: Four Wheels Benefits Problems Support more weight
Drive in a straight line
Problems
Accurate turns still difficult
Dust accumulation made rear tires slide
Still could not go over stairs

8. Axles: Two wheels + Skid
Benefits
Could support more weight than other two
Turns were more accurate
Problems
Still could not go over stairs (this objective was then abandoned)
Tape on skid would tear and accumulate dust; had to be changed frequently

9. Axles: Two wheels + skid

10. Sensor Platform Sensors Placement
2 ultrasonic sensors (facing forward and right)
1 light sensor
1 touch sensor
Placement
Ultrasonic sensors at different heights to eliminate interference
Light sensor at height of candle flame
Touch sensor had bumper attached to increase wall detection

11. Sensor Platform

12. Fire Extinguisher Baking soda used as extinguishing agent
Two cups cut near bottom used to hold the baking soda
Cups taped to mechanical arm
Arm powered by gears connected to the third motor
Gears were used to increase speed of arm instead of direct connection to motor

13. Fire Extinguisher

14. Programming Two main codes Navigation
Light Detection and Fire Extinguishing

15. Programming: Navigation
Start Loop
Turn 90 degrees to the right
Repeat Loop 3x
Exit Start Loop.
Press Start –
Robot rolls forward (Motors B and C)
When an opening is seen with a depth greater than XX cm, Brake
Random Loop
Rely on sensors to direct the future path of robot
If touch sensor (port1) triggered, robot will back up, rotate 45 degrees in a random direction
While robot is in motion, the light sensor (port3) is searching for light > 35
Once light of this magnitude is seen – exit Random Loop

16. Programming: Light Detection & Fire Extinguishing
Extinguish Mode
Arm (Motor A) swings, releasing extinguisher on flame.
End Search.
Robot moves directly towards seen light source (Motors A and B)
When Light > 75
(ultrasonic sensor – port3)
Brake.

17. Searching Pictures

18. Video

19. Lessons Learned
Beneficial knowledge in programming using different types of software
An expanded awareness of how robotics operate autonomously and the difficulty to execute a non-remote controlled program
The importance of time management in testing various components of the robot (wheel sizes, random vs. planned algorithms, different software programs, etc.)