It is fairly simple to construct a ‘singing’ melodious greeting card, as explained in the following article.
You can replicate this greeting card design through matching chips which carry about 30 popular melodious song versions in its UM3166-xx fully autonomous melody generator chip.
This electronic chip works at an incredibly low battery voltage of around 1.3 to 3 V. Nevertheless, it manages to operate a tiny piezo-buffer from antiphase output ports 2 and 4.
A piezo element is used for generating the musical output from the IC. If you think the output volume is not big enough, you can use a small audio amplifier with a small 8 ohm speaker to increase the volume
You can ensure a greeting card melody plays in a loop by bridging terminal 3 to 7 instead of 1.
The following table provides the list of tunes and popular melodies programmed in the respective UM3166 ICs.
The IC pinout details is shown in the following diagram
