The hardware is simple: A 16850 lithium-ion battery powers an MP3 Decoder/Amplifier module that plays MP3s stored on a Micro SD card. A speaker, power switch, and micro USB powered battery charger ...

Sound comes into the unit through an off-the-shelf Bluetooth module, before being passed to an ADAU1401 digital signal processing unit. From there, it’s passed to a mono amp to drive the woofer ...

The $25 MixTape Kit, aimed at those who already own a 3D printer, includes the guts of a basic MP3 player. Simply print out the enclosure using the plans on MakerBot's Thingiverse site, plug in ...