article_snippet: Above, Mayor Bill de Blasio speaks about its system .
article_snippet: Sensors in seven districts of the Bronx have already begun working, and the devices will be turned on in ten districts of Brooklyn on Monday, according to the New York Times. '
article_snippet: its system is going to do a world of good in terms of going after the bad guys,' Mayor Bill de Blasio said.
article_snippet: The company's technology is already being used in major cities such as Washington, Boston, Oakland, San Francisco and Minneapolis.
article_snippet: Seventy-five per cent of the alerts issued in Newark, New Jersey, were false alarm, according to WNYC.
article_snippet: Sensors are often placed on buildings and poles.