A dedicated and well-designed data logging shield for Arduino.
SD card interface works with FAT16 or FAT32 formatted cards. The 3.3 V level shifter circuitry prevents damage to your SD card.
Real time clock (RTC) keeps the time going even when the Arduino is unplugged. The battery backup lasts for years
Works with Arduino UNO, Duemilanove, Diecimila, Leonardo or ADK/Mega R3 or higher. ADK/Mega R2 or lower are not supported.