Description: The SparkFun OpenLog is an open source data logger. Simple to use, simple to change. We wanted to create a serial logger that just worked. Power up this device and it will start logging any received serial data at 9600bps. Sending Ctrl+z three times will drop out of logging and in to command mode. ‘new’ will create a new file. ‘md’ makes a directory. ‘?’ brings up the list of commands. OpenLog doesn’t do a lot, but it does log serial streams extremely well. Example:
>new testfile.txt >append testfile.txt <(send large amounts of text followed by three ctrl+z characters)
That’s really it! OpenLog firmware is open source and is based on Bill Greiman’s sdfatlib. OpenLog currently supports FAT16 and FAT32 microSD cards (we’ve tested up to 64GB!).
Note: New firmware is available which allows the OpenLog to be used in Arduino 1.0 and also allows for higher baud rates. Check the links below for more information.
Dimensions: 0.16 x 0.6 x 0.75" (4 x 15 x 19mm)
The OpenLog project is housed on GitHub! Please see the wiki for the most up-to-date firmware, feature requests, files, and datasheet specs.
Based on 8 ratings:
3 of 3 found this helpful:
The physical size is amazing, it’s only about the size of the MicroSD socket. Easy to use and works well, though can’t sustain 115200 bps data rates on most MicroSD cards (the ~928 byte buffer overflows in 64ms at that speed, and most MicroSD cards have a maximum write latency higher than that).
I built a flight data recorder for multirotors which uses the OpenLog as its logging device. It’s well suited for that application due to its small size, light weight, and easy set-up:
I got one of these for myself two months ago but I didn’t need it until today. I found myself wanting to capture 9600 baud messages from a new GPS module I picked up but the GPS being 3.3V and most of my kit being 5V I was pondering how to get going quickly. Aha, let’s try that OpenLog I thought!
I connected 3.3V, GND, and then just the RXI of the Openlog to the TX from my GPS module and the happy blue blinking “write” light on the OpenLog confirmed my joy.
Then just popping out the microSD I was using and looking at it on my PC I had the log file I was hoping to see. It was too simple.
I’m happy also that for future work the OpenLog will work at 5V also. It was super convenient that it worked around 3V also.
I’ll likely solder this one into my GPS for major data logging. And I’ll buy another one for the convenience of debug and test like today.
I love this product. Using Energia I was able to make it work satisfactorily. In the final system integration I encountered a few issues. One is the excessive emission that interferences with other sensitive components in my breadboard. It would be much better if the board is 4-layer with ground and Vcc planes properly utilized. The other issue is that there is no convenient way to reset the module to terminate the previous file and start anew. Poping the card out and back in is a bit inconvenient. If there is a way to add a small surface mount push button switch to short GRN momentarily with a pull-up resistor it would be perfect. I love the size of the board. It is the best I can find for doing wearable technology product development. Hope a new version will be available soon in the future. By the way, please use a 14.7345 MHz crystal so that the maximum speed of UART can be increased by another few times. Thanks.
I just opened a com port and threw data at the board. It worked great!
Simple tool for logging data. I’m using this to log flight data from an STM32F103-based ARM processor. Works well.
Its document say that can handle anything to 1,000,000. But you got very unreliable recording at 230400 or anything more than that.
Hi, Thanks for sharing this with us. We have tested this unit up to 115200 many times. It should operate fine at that speed. If you are having issues at 115200, I would recommend starting a support ticket on GitHub. We can help you more there. https://github.com/sparkfun/OpenLog We have not done much testing beyond 115200, so there may be some limitations above that.
I’m using one of these as a flight data recorder on a quadcopter equipped with a Full Naze32 flight controller running Cleanflight and it just ‘works’.
One of Cleanflight’s many options is the ability to setup a flight data recorder using the SparkFun OpenLog. Basically, you flash the OpenLog with Nicholas Sherlock’s firmware for Cleanflight, then connect the OpenLog to the FC, enable Blackbox in the Cleanflight GUI, and you’re done. Brilliant!