Logger Comparison

nseidle edited this page Feb 22, 2012 · 11 revisions

This is a quick comparison of the different FAT data loggers that we know of in the embedded world.


Yes, that’s us. We rock. OpenLog is small, cheap, and does one thing well, log data.

  • Mates directly with Arduino Pro and Arduino Pro Mini
  • Basic serial STK500 bootloader comes pre-installed so that you can tweak the firmware to your heart’s content
  • Very compact
  • Supports FAT16 (up to 2GB)
  • Very few bells and whistles
  • Based on ATmega328 @ 16MHz and 3.3V


Logomatic is pretty phenomenal. It uses an ARM7 LPC2148 and does some really cool stuff.

  • Obviously it datalogs
  • Has a USB mass storage device profile built in. So when you attach USB, you get a fancy drive on your computer where you can see the actual files on the SD card. This is nice because it doesn’t require a microSD card reader.
  • Has an external battery connector. This makes the board a very independent data logger; you don’t need any other microcontroller.
  • Has RTC for file date/time data.
  • On/Off switch is handy
  • Comes with SD+USB bootloader that allows the end user to tweak firmware for their own bubble logging projects.
  • Configuration is done through an on-board configuration file, so no need to type in commands!
  • Fairly compact for what it offers


The uLog (pronouced micro log) is a very compact data logger. It was designed for use with rocketry and accelerometers but has many applications.

  • Uses an ATtiny24 to read up to 3 channels of analog data
  • 16 mega bit on-board EEPROM is a little limiting (only 1MB of usable space across 3 analog channels)
  • Has on-board power connector which makes it very easy to use


The MicroDrive from 4D Systems is very good but we found some limitations.

  • Very well documented
  • Auto-baud feature is neat, but can be difficult for first time users
  • Has advanced features including read/write file locations
  • Upgradable firmware but not open source

The command structure is great for advanced users, but we created OpenLog because we believe 90% of users just need something basic that logs serial immediately.

SD Shields

There are various SD shields for the Arduino including SparkFun’s microSD Shield and AdaFruit’s GPS logger shield kit. These work very well, but in general require the FAT code to be located on the Arduino’s ATmega. We wanted to offload the work of the fairly involved details of the FAT filesystem and SD card to a separate processor. Remember, your project should be your project – don’t get hung up on the peripheral requirements.

JPEG Trigger

Yes, it can be reprogrammed to work similarly to OpenLog. It doesn’t come with the arduino bootloader, and the crystal is slightly different, and you have one big RGB LED instead of two tiny greens, but you also have more pins to play with and can talk to more “standard” baud rates – 921600, 460800, 230400, 115200 (much more exact).

OpenLog Wiki Pages:

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