Homemade Portable MP3 Player

The circuit utilizes an Atmel Atmega128 AVR microcontroller to create a small and portable MP3 stick.

In the design, a VLSI VS1011b decoder IC is used to decode the MP3 with the memory medium of MP3 files, skin files, and playlist files using MMC/SD card. A LiLo/LiPo battery with 3.6V is used to provide power for the design of the circuit and also includes a charger circuit based on MAX1811. A Nokia color LCD with 128×128 pixel and 256 colors is used to show all information. Nice graphic skins will be shown if a skin is available although the player will work in text-only mode. Outside connectivity for audio signals, charger voltage input, and serial control signals is allowed using a docking port.

The main microcontroller used is an ATmega128L-8A that runs at 8MHz internal RC oscillator. A low drop fixed voltage regulator LM2940 is used to supply 5V to battery charger from 5-26V input voltage while the main 3.3V power supply comes from LP2981 low drop fixed voltage regulator. The Nokia 6610 LCD connects through DF23 connecter and the LCD backlight is powered by white LED driver. A 3.5mm audio jack is available.

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