How fire sensor works?

Answer 1

San Diego--Wildfires often begin unnoticed, spreading quickly, with devastating consequences. Homeowner Dorothy Roth is still in shock three years after a wildfire raged through her backcountry community in Southern California. She lost everything.

"We were so lucky to get out. I mean, another 30 seconds, and we probably wouldn't have been able to get out," Roth says. She had no warning the fire was so close. "There was no smoke, and there were no flames to be seen ... at all."

Ecologists from the Ecological Reserve in Fallbrook, Calif., are working on a project called FireAlert that can give homeowners like Roth an early warning of an impending wildfire. The project consists of wireless sensors that are able to spot a fire in its earliest stages, up to six miles away.

John Kim, ecological information management researcher from San Diego State University in San Diego, says, "[The sensors are made of] a mirror that rotates 360 degrees, which takes the reflective signal from the horizon. And it goes into a sensor device that's looking for a specific signature of heated carbon dioxide."

Once the signature Kim describes is sited, the wireless sensors quickly determine the fire's precise location and the sensors continue to send information to a central computer indicating direction and size of the fire. Steve Abbott, division chief of San Diego North County Fire Protection District, says, "What this technology gives is the opportunity for communications centers and emergency response personnel to know when a fire is occurring."

Roth believes a web of sensors can give both homeowners and firefighters a fighting chance and says, "It certainly has the potential to be a huge lifesaver."

The fire sensor network is already capable of sending information to a computer network. The system can also notify people by phone or e-mail when a fire is near their home. San Diego State University researchers plan to install 13 sensors in the Santa Margarita Ecological Reserve over the next two-and-half years.

BACKGROUND: Scientists at San Diego State University are creating an early-warning system for fire outbreaks, equipped with sensors so sensitive they can spot a fire up to six miles away. The researchers will install 13 sensors -- foot-long metal cylinders about 5 inches thick -- in the 4300-acre Santa Margarita Ecological Reserve near San Diego.

HOW IT WORKS: The fire sensors are solar powered and have a life span of about 20 years. Each sensor contains a rotating mirror that searches for any unexpected changes in the heat of the atmosphere around it. All objects give off some kind of heat -- known as infrared radiation -- but the hot carbon dioxide given off by a fire has a specific "signature." This means that the sensors can tell the different between heat from fires and from non-fire sources, such as car exhaust. Once the sensor detects something, the mirror stops rotating and stays pointed in that direction. It uses radio signals over a wireless network to transmit the data to towers or satellites, helping firefighters to quickly determine the precise location of a possible fire.

BENEFITS: Early detection of fires would allow firefighters to take action before fires roar out of control, destroying lives and homes.

WHERE TO FIND IT: The system is called FireAlert. It is manufactured by Ambient Control Systems, based in El Cajon, California. But the sensors are expensive, retailing for about $12,000 each, so groups of homeowners may want to share the costs. They would also have to pay an annual subscription fee of a few dollars for notification services when a fire is near their homes.

WHAT IS SOLAR POWER: Solar power is a form of renewable energy that harnesses the sun's emissions of heat or light. But technically, solar power helps form fossil fuels such as petroleum and coal. These are the result of decayed plant matter that absorbed solar energy when alive; fossil fuels are the concentrated stores of that original solar energy.