SDLogger - Open Hardware Data Logger


SDLogger is a simple serial logger based on SparkFun/Nathan Seidle’s OpenLog. It is using an ATmega644P processor running at 14.7456MHz and logs to full-size SD cards. It supports both standard SD cards (FAT16) and SDHC cards (FAT32). SDLogger ships with OpenLog firmware 1.61 installed (compiled with SDHC/FAT32 support and large 2048 character input buffer) together with an Arduino-compatible bootloader for easy program update.


  • Simple to configure and use

  • Automatically logs data received on the serial input port

  • Can be configured using a config file on the SD card

  • Supports 2400, 4800, 9600, 19200, 38400, 57600, 115200 and 230400 serial baud rates at 8-N-1.

  • Supports both standard SD cards up to 2GB (FAT16) and SDHC cards up to 16GB (FAT32)

  • Large input buffer (2048 characters)

  • Full-size SD card form factor

  • 14.7456 MHz crystal oscillator for precise baud rate generation

  • Input voltage range: 3.3 to 12V

  • Arduino-compatible bootloader installed for easy program update

  • Full Arduino environment support - can be used as an inexpensive Arduino board for program development

  • I/O ports supported in Arduino environment (in addition to the main serial port): 4 analog inputs, second serial port, I2C port

  • Simple SDLogger original firmware restore procedure using the Arduino environment

  • SDLogger hardware/firmware designed by Saanlima/Magnus Karlsson and released under CC BY-SA v3 license

  • Design files, Arduino code and other ported code available on GitHub


  1. SDLogger wiki pages

  2. OpenLog wiki pages (Much of the information here is also relevant to SDLogger)


  1. The FAT16/FAT32 firmware was originally designed by Roland Riegel and is released under GPL v2.

  2. OpenLog hardware and firmware developed by SparkFun/Nathan Seidle’s OpenLog and released under CC-SA v3 license

  3. Arduino SdFat library written by Bill Greiman and is released under GPL v3

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