I am a computer science student and recently interest built into electronics . I want to ask how can i download custom audio in musical toys like this . All i have is this kind of phone toy, Please tell what else i need to purchase to do this DIY.
Not directly to your youtube solution, but hope this helps: When in university I've made such a "toy-music" with AtTiny13 MCU. It is a small 8-pin chip.
You simply need to write the music byte by byte in the form like "note", "duration", "note", "duration" and then provide basic code which fetches bytes one after one and turns on the required tone (with an onboard timer) for specified duration. This appeared to be "as easy as lying" even though I have close to zero experience with MCUs at that time.
To upload new music you simply compile your code again with different array of bytes and write it again to the chip.