SparkFun OpenLog Open-source data logger works over a simple serial connection Supports microSD FAT16/32 cards up to 32GB Configurable baud rates up to 115200bps Preprogrammed ATmega328 and bootloader

Awsome

This is a great little device for logging serial output from a microcontroller. Just connect to the UART and it's preprogrammed to record output. I'm using it to record sensor output to an SD card. The firmware can be customized as needed, but I just used the firmware it shipped with.

The logger is great when it works, however the mechanism that holds the SD card in place is extremely fragile and does not last long, I've ordered more than 10 over the past couple of weeks and every single one broke within a couple of days of continuous use. Can not recommend.

Only for technicians. It sits in a drawer unopened. No idea how to use it.

This little board is great. In only a couple hours I had it logging serial data from my Arduino to an SDCard. I started to follow the instructions from SparkFun to download a new program to it via an FTDI interface adapter, but I realized soon enough that the built-in program was all I needed so I can use it right out of the box. YOu can directly connect the TX/RX pins to their mating RX/TX pins on an Arduino (or any other TTL serial data stream and it captures the data to a LOG file on the SDCard automatically. I only wish for a clock/cal to time stamp the logs, and the ability to run faster than 9600 baud without worry of missing data. For the price, size and performance...It's GREAT!