This is an interesting hobby circuit for students. This DIY electronics project circuit will generate 4 different sirens such as police siren, ambulance siren, fire force siren and gun firing sound. Low power CMOS UM3561 ROM IC is the main component of this DIY Project circuit, which is designed to generate the sirens. This DIY Project circuit is very useful for many low voltage alarm circuits.  

Working of Different Siren Generator DIY Project:

This DIY electronics project requires only a 3V power supply. Switches S1, S2 and S3 are connected to Pins 1 and 6 from the tone selector section of the IC. Frequency of the oscillation can be controlled by external variable resistor connected between 7th and 8th pin of UM3561 IC. Output from the 3rd pin is capable of driving a piezo. But to drive 8Ω speaker amplification is needed.  So a transistor BC337 is used to drive the 8Ω speaker. Switches S1, S2, S3 are used to select the tone. When 3 switches are open there is no connection to pin 1 and 6 so the circuit will produce police siren. While pressing S1, only pin 1 gets 3V supply and produce gun firing sound. Pressing switch S2 will produce fire force siren. When pressing S3 pin 6 will get grounded and produce ambulance Siren. Further amplification can be done using a LM386 amplifier.

Circuit Diagram and tone selection method of this DIY electronics project are given below. The entire electronic components list needed for this DIY Project circuit is given below. Make the circuit using these components as shown in the circuit diagram.

different siren generator circuit diagram

circuit diagram

Siren Generator Tone Selection:

siren generator project

Pin 1

Pin 6

Tone

NC

NC

Police Siren

NC

3V

Fire Force Siren

NC

Gnd

Ambulance Siren

3V

NC

Gun Firing Sound

Electronic Components:

Resistors:

  • 100K Variable Resistor – 1
  • 150K Resistor – 1
  • 10K Resistor – 1

Semiconductors:

  • BC337 Transistor – 1
  • UM3561 IC – 1

Miscellaneous:

  • 8Ω Speaker – 1  
  • Battery 3V – 1
  • Switches – 3

Applications of Different Siren Generator DIY Project:

  • This DIY Project can be used as a toy and also for producing different horns in vehicles. 
  • Can be used as an alarm.
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