4 Siren Sound Generator using UM3561 – Police Ambulance Sound

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Contents hide
1 Hardware Components
2 UM3561 Pinout
3 2N3904 Pinout
4 Siren Sound Generator Circuit
5 Working Explanation

A four-siren sound generator is a simple siren circuit that is mostly used in devices such as Police sirens, Fire engine sirens, Ambulance sirens, etc. It can produce up to four distinct sounds varying in intensity & pitch. So, in today’s tutorial, we will go over a step-by-step process on how to design a Four Siren Sound Generator using the UM3561 Sound Generator IC.

The heart of this circuit is the UM3561 sound generator IC. UM3561 is an outstanding ROM (Read Only Memory) IC. The main function of this chip is to produce different siren tones like Ambulance, Police, machine gun, and Fire brigade siren sound. The typical operating voltage of UM3561 is 3V and the operating Current is 150μA. The output current of UM3561 is 3mA. It is a low-cost IC mainly designed for toy applications.

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Hardware Components

The following components are required to make Siren Sound Generator Circuit

S.noComponentValueQty
1.Sound Generator ICUM35611
2.Variable Resistor100K1
3.Transistor2N2222, 2N39041
4.Four Siren Sound Generator PCBAllPCB1
5.Push button–3
6.Loudspeaker8 Ohms1
7.Resistor10K, 150K1
8.Terminal Block Connector3.5mm1
9.Soldering Iron 45W – 65W1
10.Soldering Wire with flux–1
11.DC Battery3V1
12.Battery Clip–1
13.Soldering stand–1
14.Jumper wires–As per need

UM3561 Pinout

um3561-pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of UM3561

2N3904 Pinout

2N3904-Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N3904

Siren Sound Generator Circuit

Working Explanation

The working of this four-siren sound generator is based on the operation of the UM3561 IC. here, the oscillator generates the necessary clock pulse for the operation of the IC. The frequency of the oscillation is determined by the resistor connected to pin 7 (OSC1) & pin 8 (OSC2) of the IC.

A 220K Ohm resistor is connected across pins 7 & 8 to acquire the output. The output generated by the UM3561 IC is not enough to drive the 8 Ohm loudspeaker. In order to amplify the output of the UM3561 IC, a BC547 transistor is used at Pin 3 (OUT) of the IC.

Applications

  • Commonly used in devices like small toy cars & trucks.
  • Also used in the sirens of law enforcement & medical (EMT) vehicles such as police cars & ambulances respectively.

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