Multi Melody Generator Circuit Using UM3481 IC

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Multi Melody Generator is a circuit that can function in any electronic project where you need to generate a melody. For this Multi Melody Generator project, the IC we are using is UM3481.

UM3481 is a mask ROM programmed IC implemented by CMOS technology, designed to play melody according to the previously programmed data. It is capable of generating 8 different types of melodies with 3 different instrument tones: piano, organ, and mandolin. It also includes a pre-amplifier which provides a simple interface to the driver circuit.

This IC is very convenient you just have to use very few external components because all the important circuitry is built-in, it has low current consumption, and can operate on only 1.5V to 4.5V DC. This IC can replace other ICs in the UM348xx series. They all produce different melodies and you can select them based on your desired melody.

Hardware Components

The following components are required to make Melody Generator Circuit

S.no	Component	Value	Qty
1.	IC	UM3481	1
2.	Switch	–	1
3.	Transistor	2N3904	1
4.	Speaker	8 ohms	1
5.	Resistor	1K, 100K, 220Ω	1, 1, 1
6.	Ceramic Capacitor	47pF	1
7.	Battery	3V	1
8.	Breadboard	–	1
9.	Battery clips	–	1
10.	Connecting Wires	–	1

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For a detailed description of pinout, dimension features, and specifications download the datasheet of UM3481

2N3904 Pinout

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

Melody Generator Circuit

Working Explanation

Working on this circuit is quite simple because the IC that we are using has built-in circuitry. We are only using a switch, a transistor for amplification, and a speaker to generate our output melody.

This circuit is powered by a 3V battery. Switch S1 functions as an input select switch, each time S1 is triggered, a new melody will generate. We have used a capacitor for noise cancellation. The output generated from pin11 of the IC is fed to a speaker-driven transistor. The transistor that we are using is 2N3904, it amplifies the output to drive the speaker. The speaker should be 8ohms, different resistors are used at the input of the switch, IC, and transistor to limit the base current.