Someday, umbrellas may do more than just keep people dry. A researcher in the Netherlands has designed a simple sensor (传感器) that "listens" to rain. And that sensor can turn an umbrella into a rainmeasuring expert. Tools like this can let anyone gauge the weather. That can help scientists make sure that radar (雷达) systems that track storms are doing a good job.
"Rain radar is a beautiful way of seeing where rainfall(降雨量) is up in the air. But you never know where it hits the ground," says Rolf Hut. He designed the umbrella sensor.
Researchers want to know how much rain makes it to the planet's surface. Not all rain that falls from a cloud reaches the ground. And it can be difficult for radar to measure that rain, particularly in cities. A host of big buildings can change how air and rain move during a storm. "It also explains why a single, expensive sensor—the kind that might be found at an official weather station—won't give accurate citywide data, " says Hut. But by putting a lowcost rainmeasuring tool into people's hands, scientists can learn more about how much rainfall differs in these and other hardtomeasure places.
On the inside of the umbrella is a small, yellow disk. It is the rainfall sensor. The sensor is attached to a black Bluetooth headset that sends the collected data to a smartphone.
Hut came up with the idea to stick the same type of sensor on an umbrella when he was talking to kids about science. He showed them a photo of a policeman who was holding an umbrella and talking to a crowd in a microphone. Why not put the two together? He thought it could make a cool rainfall sensor.
When a storm came, Hut compared the umbrella's new "ear" for rain to official rainmeasuring equipment. And to his delight, he found the umbrella's measurements were "pretty good". His next step is to improve the umbrella sensor to make it more accurate.
