Police Siren, Ambulance Siren and Fire engine Siren by UM3561 (Part 1 of 2)
Sirens are essential in our daily life to give warnings and signals. We have heard many sirens like police siren, ambulance siren, fire engine siren etc. Generation of these sirens were very difficult in early days. Bu today, due to the development of electronics, it is very simple to generate such sirens. UM3561 is a simple IC which helps us to generate four sirens easily. They are police siren, ambulance siren, fire engine siren and machine gun sound. Output will be obtained through the speaker (I am using a 3 W, 4 Ohm speaker).
Circuit is done as shown in the following diagram. Three switches are given in the circuit to choose the desired siren. 2SC9013 is an amplifier which amplifies the signals coming from UM3561.