Fighting fire with sound

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Ainsley Swartwout and Maria Parnell with “UV-Chan,” their flame-seeking, sound-waves firefighting robot.
Photo by Regina Carson

By REGINA CARSON

At the Roanoke Valley Governor’s School for Science and Technology, students are charged each year with carrying out a science fair project.

Occasionally, students get so interested in their work that it becomes a multi-year commitment, and that is what happened this year with Lord Botetourt High School juniors Maria Parnell and Ainsley Swartwout.

Last year the two teamed up to investigate the effect of sound frequency on flame suppression, and this year, they decided to add a robot to the mix.

Both projects won first place at the Governor’s School’s Project Forum, and this year’s project, “Acoustic Fire Extinguisher,” will compete next at the Western Virginia Regional Science and Engineering Fair in March.

“Most fire extinguishers put out fire with compressed chemicals,” said Parnell, “and the chemicals often harm the environment, damage sensitive equipment, or have deployment issues. But concentrated sound pressure waves can extinguish fires by displacing the oxygen that sustains them, and we thought if we could put that on a flame-seeking robot, it would really benefit society.”

“So our goal this year,” said Swartwout, “was to create an autonomous robot that could consistently sense flames, navigate toward them, and extinguish them with a subwoofer speaker.”

Like most projects at the Governor’s School, this one was complicated. To construct the robot, the girls added four wheels to a chassis, fastened on six ultrasonic PING sensors and a sound amplifying board, and attached two lantern batteries to provide power to the board.

Next they attached two tubes to the speaker to concentrate the sound waves, and then they mounted the speaker on top of the batteries.

Finally, to the top of the speaker they attached a pan and tilt mechanism they created to hold the flame sensor board, hooked four infrared flame sensors to the tubing, and voilà! “UV-Chan” had arrived.

To control the robot, Parnell and Swartwout programmed three Arduino microprocessors; one to control the pan and tilt and receive input from the flame sensors, another to control the speaker and receive input from the PING sensors, and a third to control the wheels.

The Arduinos communicate with each other through XBee devices that the girls configured to work together to accomplish their goal.

Once a fire activates the flame sensors, the process begins, and the information collected guides the robot to move toward a flame, maneuver around obstacles, control the speaker to extinguish the flame, and then scan for other flames.

Wow! What a great project!

But does it work?

“It does!” exclaimed Parnell. “We used wood blocks and an oil lamp to create three different obstacle and flame scenarios, and after 30 trials, UV-Chan was 100 percent successful in navigating obstacles, 30 percent effective at aiming at and extinguishing a flame, and 40 percent effective at detecting a flame at a distance.”

“We’ve only scratched the surface with our experiment, though,” said Swartwout. “The future holds great promise for this technology.”

As it clearly does, too, for Maria Parnell and Ainsley Swartwout.

Parnell and Swartwout are just two of the 264 gifted and talented young scientists who attend Roanoke Valley Governor’s School for Science and Technology. To learn more about the Governor’s School, a half-day regional public STEM school for motivated students in grades nine through 12, visit the school’s website at http://www.rvgs.k12.va.us or contact the school’s director, Mark Levy, or the school’s guidance counselor, Kathy Sebolt, at 853-2116.