The AVR Butterfly MP3 player is an innovative open source project that allows hobbyists to build a fully functional MP3 player from scratch.
It demonstrates how the powerful AVR Butterfly microcontroller development board can be turned into a customizable personal audio device with just a few additional components.
At the heart of the project is the AVR Butterfly board from Atmel. This compact board contains an ATmega169V 8-bit AVR microcontroller running at 10MHz, along with interfaces for a display, buttons, battery power, and expansion ports. The ATmega169V provides more than enough processing capability to decode MP3 audio files in real-time.
To handle the MP3 file decoding, the project incorporates the VS1001 chip from VLSI Solution. This specialized decoder chip takes care of unpacking the compressed MP3 audio so the microcontroller only needs to feed it the encoded data. It can handle files up to 320kbps, providing excellent audio quality.
The VS1001 connects to the AVR chip via an SPI interface. To store the audio files, a microSD card slot is added to the Butterfly board. A simple headphone jack provides the analog stereo audio output. The microcontroller can drive the LCD screen and buttons built into the Butterfly board to allow the user to navigate and select songs.
One of the appeals of the project is its simplicity and low cost. The total bill of materials can be less than $20. With basic soldering skills, the VS1001, microSD slot, and headphone jack can be integrated onto the development board. The open source code handles the graphics, file system, and MP3 decoding.
Overall, the AVR Butterfly MP3 player provides an easy entry point into DIY audio projects and embedded systems. Following the step-by-step instructions, anyone can build a fully functional MP3 player with hours of storage in a tiny package. It’s an exciting example of leveraging open source software and affordable hardware for custom projects.