Robo Fire Fighter

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Robo Fire Fighter builds on the skills learned in Robo Race. It introduces the concept of light finding. Robo Fire Fighter also introduces sensor stacking.

Mission Objective

Build the fastest autonomous robot that will locate and extinguish a fire (candle) while following an unknown path.

Figure 1. Robot Approaching Fire

Race Rules

The robot must pass an inspection before the race starts to ensure no construction rules have been violated. The robot team will have a chance to make modifications before the race starts.
When commanded, the robot driver will press the green “run” button and the clock will start.
The robot must follow the path until it reaches the end.
At the end, the robot must turn around.
The robot must follow the path back to the home position.
Upon reaching the home position, the robot must come to a complete stop and the motors must be turned off.
The Robo Fire Fighter must extinguish the fire using only a motorized fan.

Figure 2. Candle holder.

The robot may not touch the fire.
The fire may be placed at any turn in the path

Figure 3. Possible light locations.

Each robot's run is timed from the time the run button is hit to the time it returns to the home position and comes to a complete stop.
Each contestant may request a new candle be used for their fire. However, unless specified by the contestant, changing the candle is at the discretion of the referee.

Robot Construction

The robot must be less than 11 inches long including any extensions.
The robot must be less than 10 inches wide.
The robot may use any number of Lego sensors and bricks.
Once started, the robot must be completely autonomous.
You may need an external motor and power supply for the fan. These can be acquired from any local hardware shop. To make an external motor and power supply, see Appendix # for details.
You can make a fan blade from model airplane propellers. These can be picked up at any local Hobby Shop.

Figure 4. Sample fan used in Robo Fire Fighter

Violations

Major Infraction

When a major infraction occurs, the robot must be restarted from the beginning of the track without stopping the clock.
Once the robot is moving, there can be no human intervention until the robot completes the task.
The robot cannot leave the track during the race.
Losing pieces while the robot is running the race.
If an error occurs and it appears the robot will not finish the race.
Touching the fire with any part of the robot will incure a major infraction.

Minor infractions

Failing to come to a complete stop when returning home incures a 10 second penalty added to your time.
Failing to extinguish the fire will incure a 2:00 minute penalty added to your time.

Determining the winner

The racer with the shortest time, after violations, is declared the winner.
In case of a tie, the tied contestants are allowed a run-off. The racer with the shortest run-off time is declared the winner regardless of their initial time.

Playfield

See the Build a Race Track activity for help building the track.

Materials

8-12 white bookshelves, approximately 10”x36”x1/2”. These can be obtained from any local building center.
Black electrical tape, approximately 5/8” wide.
Standard birthday candles.
Matches or lighter.

Construction

Layout the bookshelves on a flat surface in any connected open pattern.

Lay a strip of tape in a smooth line in the middle of the boards.

On day of the event, the referee will place the fire in accordance with the rules above.

Hints

Use a stacked light sensor and touch sensor to look for the fire. In this configuration, when the light sensor senses a reading above 80, then this means that the touch sensor is active. Readings below 80 represent true light readings. Candles often give a reading of about 60.

Use a semaphore to turn off the light sensor watchers while turning around, stopping, and blowing out the fire.