Police LED Flasher Using 555 Timers

Police LED Flasher Using 555 Timers

There are many types of emergency vehicle lights that installed on police cars, fire engines, ambulances, etc. This post presents circuit for blinking alternately the two red LEDs and two…
Police Siren Using 555 Timers

Police Siren Using 555 Timers

This post presents circuit which produces a long up and down variation of the sound that similar to police siren. Circuit is based on two 555 timers which operates in…