UM66 IC and UM3561 IC for Melody and Sirens generation

(Last Updated On: September 5, 2021)

UM66 IC and UM3561 IC:

UM66 IC and UM3561 IC for Melody and Sirens generation- The UM66 and UM3561 ICs can be used in places where you need to generate melodies and Sirens” Police Siren, Ambulance as well as the Fire Engine siren”. In this article I will talk about both the Ics in detail and I will also share circuit diagrams.



UM66 IC:

First, we are going to start with the UM66 IC which is basically used as the melody generator.

Components Required:

You will need the following component in order to build this circuit:

  • A UM66T melody generator IC
  • BC547 NPN Transistor
  • 1x 100Ω resistor
  • 1x 220Ω resistor
  • 1x 4.7KΩ resistor
  • 1x 5mm LED
  • 100uF electrolytic capacitor
  • 1uF ceramic capacitor
  • SPDT Slide Switch
  • 3Ω speaker
  • 5V DC power adapter

Circuit Diagram of UM66 melody generator:

UM66 IC UM3561 IC

Now to make the circuit we will connect the positive terminal of the battery supply with the switch to turn on and off the circuit. The other terminal of the switch will be connected with the 220 ohm resistor and 100 ohm resistor. The second terminal of the 220 ohm resistor will be connected with the anode of the led in order to limit the current and cathode of the led will be connected with the ground or negative terminal of the battery. Now the other terminal of the 100 ohm resistor will be connected with the positive terminal of the 100 micro Farad capacitor and negative terminal of the capacitor will be connected with the negative terminal of the battery and another capacitor of 0.1 micro Farad will be connected in parallel with the 100 micro Farad capacitor. Now the pin number 2 of the UM66T will be connected with 0.1 micro farad capacitor and with the speaker. The pin number 3 of the UM66T will be connected with the 4.7 KΩ resistor and the other terminal of the resistor will be connected with the base of the BC547 transistor the emitter of the BC547 will be connected with the ground and collector of the BC547 will be connected with the other terminal of the speaker.




UM66T:

The UM66T series is a CMOS LSI designed melody generator IC for use in telephones and toys

application. It has an on-chip ROM programmed for musical performance. Produced by CMOS

technology, the device results in very low power consumption. And with built-in RC oscillator, a

compact melody module can be constructed with only a few additional components.

UM66 IC UM3561 IC

UM66T also known as the BT66T. The UM66T is a 3 pin IC. Pin 1 and 2 are the power supply pins. Pin 3 is the output pin. The IC has an internal oscillator which sets the rhythm and tempo of the tune stored within its internal ROM.

Absolute Maximum Ratings

DC Supply Voltage …………………………….. -0.3V to +5.0V

Operating Ambient Temperature ………….. -10°C to 60°C

Storage Temperature …………………………… -55°C to 125°C



Circuit working:

The schematic shows how the electronic components are connected to the UM66T.

The 220Ω resistor reduces the current flowing through the LED. The 100Ω resistor reduces the input supply voltage. An SPDT switch is used to turn the circuit ON and trigger the IC. The LED indicates when the circuit is switched ON. The 4.7KΩ resistor controls the amount of current entering the transistor’s base. The transistor acts as a switch thereby amplifying the output audio signal. The UM66T generates the audio signal when triggered. The two capacitors are used to filter out any noise. I soldered all the electronic components to the PCB including the speaker and the power adapter. When the switch will be turn on the melody will start and when the circuit will turn off the melody will stop.

Siren Generator using UM3561:

Now we will make a Siren Generator using the UM3561. It can produce a Police, Ambulance as well as the Fire Engine siren.

Component required:

You will need the following components to build this circuit:

  • UM3561 Siren Generator IC
  • BC547 NPN transistor
  • 2x 220Ω resistor
  • 1x 220KΩ resistor
  • 1x 5mm LED.
  • 1x SPDT Slide Switch
  • 1x SP3T switch
  • Battery
  • 1x 3Ω speaker



UM3561:

UM3561 is a low-cost, low-power CMOS LSI designed for use in alarm and toy applications. Since the integrated circuit includes oscillator and selector circuits, a compact sound module can be constructed with only a few additional components. The M3561 contains a programmed mask ROM to simulate siren sound.

UM66 IC UM3561 IC

The UM3561 is a low-cost, low-power integrated circuit that has 8 pins. Pin 1 and 6 are used to select the siren tune. Pins 2 and 5 are the power supply pins. Pin 3 is the output pin. Pin 7 and 8 are used to configure the oscillating frequency and finally, Pin 4 is not connected to anything.

Absolute Maximum Ratings

DC Supply Voltage …………………………………… -0.3V to +5.0V

Input Voltage Range ……………………………….. Vss-0.3V to Vdd+0.3V

Operating Ambient Temperature ……………….. -10°C to +60°C

Storage Temperature ……………………………….. -55°C to +125°C

Siren Generator Circuit diagram using UM3561:

UM66 IC UM3561 IC

First we will connect the positive terminal of the battery with the switch and another terminal of the switch with the positive terminal of speaker and also connect 220Ω resistor with the led and cathode of the led will be connected with the ground. Now connect the collector of the BC547 transistor with the speaker and connect the emitter with the ground. Connect the base of the transistor with the 220 Ω resistor and connect the other terminal of the resistor with the pin 3 of the UM3561. Connect pin number 8 with 220kΩ resistor and other terminal of the pin number 7 of the UM3561. Connect pin 2 of the UM3561 with the ground and pin 5 of the switch. Connect pin 5 of the UM3561 with pin 4 of the switch. Connect pin 6 of the UM3561 with the pin 2 of the switch.



Circuit working:

Now let’s have a look at the schematic. Only one of the siren Tunes can be generated at a time. This is determined on the basis of the position of the SP3T slide switch. The switch has three positions which will connect the common terminal with VCC, Ground or leave it not connected in order to fulfill the truth table show previously. A dynamic speaker is driven via an external NPN transistor. An SPDT slide switch is used to turn the circuit ON & OFF.An LED is used to indicate when the circuit is switched ON. The circuit needs a 3V power supply and hence uses two 1.5V AA batteries connected in series.

The 220Ω resistors are used to limit the current flowing through the LED and the transistor’s base. The 220KΩ resistor sets the oscillating frequency of the UM3561. You can vary this resistance in order to change the output frequency. I soldered all the components in place.

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About the Author: Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...

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