Testing UM66T Melody Generator IC

 I am trying to make a PIR sensor based kind of alarm system which when senses someone in its detection zone automatically plays some song's melody and thus providing warning that there is somebody. Maybe for example, this maybe used infront of the house door to sense and sound the alarm or trigger the song melody. For this I needed something that generates such sounds. What I found is this UM66T melody generator IC that can generate melody. There are different melody you can choose from UM66Txx where xx stands for different code number which corresponds to different melody. In my case for example, I have UM66T19 which generates "For Elise" song melody. 

The UM66T melody generator IC does not even look like an IC that we are used to. It looks like a transistor. Below is a picture of how UM66T19 IC looks like.

Testing UM66T Melody Generator IC

It just got 3 pins- power supply(Vdd), ground(Vss) and the melody output. Power required is 3V and the output melody signal is also 3V. This small IC contains lot of things inside like oscillator, tone generator, melody ROM too, tempo generator,beat generator etc.


Testing UM66T Melody Generator IC

To test this melody generator IC I used the schematic provided in their product datasheet. There are couple of circuit diagrams in the datasheet but I used the one shown below.

UM66T circuit wiring

As you can see, the wiring diagram for this melody generator is fairly simple. But the datasheet recommended transistor 2SC9013 which for me was difficult to find for me. I wanted to use regular NPN transistor like 2N3904 or 2N2222 transistor. So after couple of tries I found that it would work with any of the 2N3904 or 2N2222 transistor. But what you need to do is to use lower value of base resistor instead of 4.7KOhm as shown in the datasheet. I used 1KOhm resistor. Also there is difference between using 2N3904 and 2N2222 transistor. 2N2222 yields louder sound than 2N3904, apparently because 2N2222 transistor can source more current than 2N3904. 

So the modified wiring schematic diagram is shown below.

modified UM66T circuit wiring

Testing UM66T Melody Generator IC on a Breadboard

The above circuit was realized and tested on a breadboard as shown in the figure below.

UM66T Melody Generator IC on a Breadboard

Once I heard the melody sound playing, I was very pleased. If you want to hear the sound too watch the following video.

Video demonstration of UM66T melody generator 

Leave comment if you have any suggestion or questions.

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