How does an ambulance light 🚨 work?

#ambulance #emergencylight #awerness
Mechanical sirens blow air through a slotted disk or rotor. The cyclic waves of air pressure are the physical form of sound. In many sirens, a centrifugal blower and rotor are integrated into a single piece of material, spun by an electric motor.
Most fire engines and ambulances have a coded infrared strobe mounted on top of the vehicle. When the strobe is activated, it is detected by a sensor at the signal that turns the signal green for the approaching emergency vehicle.