SparkFun OpenLog

The SparkFun OpenLog is an open-source data logger that acts as a "black box" for your digital project. This board can be a lifesaver and works over a simple serial connection to store large amounts of data on a microSD card. Whether you are debugging a complex robot, recording scientific sensor data in the field, or capturing weather trends from your home office, the OpenLog captures it all without requiring complex code!

Simple "Set and Forget" Logging

The best part of the OpenLog is its simplicity. It connects to your microcontroller via standard serial pins. Once powered, anything you "print" to the serial port is automatically saved to a text file on the card.

• Massive Storage: Supports microSD cards from 512MB up to 32GB (FAT16 and FAT32).
• Low Power: The efficient ATmega328 architecture draws only 2-3mA in idle mode and 10-20mA while writing, making it ideal for battery-powered deployments.
• High Performance: Runs at 16MHz with an onboard resonator, enabling it to keep up with steady streams of serial data.

Hardware That Works

We designed the OpenLog to be small enough to tuck into any enclosure and flexible enough to handle any job. It is a standalone development board that is pre-programmed and ready to use.

• Simple Interface: A standard 0.1"-spaced FTDI header (VCC, GND, TX, RX, DTR) makes it easy to plug directly into an Arduino, Raspberry Pi, or custom PCB. (headers not included)
• Configurable: Want to change the baud rate? No need to recompile code. Just edit the config.txt file on the SD card, and you're done.
• Open Source: Both the hardware and firmware are completely open source. Advanced users can tweak the code to trigger logging based on specific events or thresholds.

If you need to log data faster (up to 500,000bps) or want to automatically log data from Qwiic sensors, make sure to check out the SparkFun OpenLog Artemis instead.

• Schematic
• Eagle Files
• Hookup Guide
• GitHub Hardware Repo