This week on the Great Search, we're taking apart a McDonalds McNugget Tetris game (https://tetris.wiki/Tetris_(McDonald%27s)) given away in China for the 40th anniversary of the chicken mcnugget.
Unsurprisingly, it's an epoxy blob'd chip that does just about everything! For the background music, a disc piezo is used to make the beeps. We've covered magnetic buzzers before (https://blog.adafruit.com/2020/11/24/the-great-search-piezo-and-magnetic-buzzers-thegreatsearch-digikey-digikey-adafruit/) on the Great Search, which we use on some of our design for SMT tone-making.
At a 500K build, budget is going to be the most important concern, so instead, we can go for a ultra low cost piezo disc! Let's take a look at what is available at DigiKey and the differences between magnetic and piezo buzzers.
See the chosen part on DigiKey https://www.digikey.com/short/dtbmq7jm