The Los Angeles Police Department is adding new technology to its black-and-white patrol vehicle fleet, including upgraded sirens designed to alert drivers sooner and improve safety. The so-called ...

Sometimes the cops absolutely positively have to get every single driver out of their way. That's what sirens are for, and Jalopnik readers have picked out the ten coolest from around the world. What ...

This is a simple circuit which produces a sound similar to the police siren and is built using NE555 Timer. Two 555 timers act as an astable multivibrator. Here is the simple circuit designed to ...