Pocket radio powered by a tiny microcontroller

Before the days of MP3 players and smartphones, and even before portable CD players, those of us of a certain age remember that our cassette players were pretty much the only way to carry music on the go. If we were lucky, they also had a built-in radio when the single band exhausted both sides. Compared to the days, it's much easier to build a portable radio even if cassette tapes are largely forgotten, as [wagiminator] shows us with this radio design based on an ATtiny.

The build is about as compact as it gets, with the aforementioned ATtiny 402/412 as its core, it also uses an integrated circuit FM tuner, an integrated audio amplifier with its own single speaker and a small display OLED. The unit also has its own lithium-polymer battery charger and its user interface consists of just three buttons, many for browsing radio stations and controlling volume.

The whole build fits easily in the palm of one hand and is fully capable for a mobile radio, and all schematics and code are available on the project page. Although it does not include AM capability, the mere fact that FM is so accessible today when a few decades ago it was cutting edge technology is quite remarkable. If you're looking for an even smaller FM receiver without some of the bells and whistles of this one, check out this project as well.