Jean Wlodarski writes:

I just finished developing my USB temperature logger and shot a video showing how it works. Here are the key figures:

• Up to two months of logging with a single coin cell battery.
• 30 000 timestamped temperature measurements.
• Logging period from every 5 seconds to every 24 hours.
• 0.5°C accuracy, 0.06°C resolution.
• No driver, no software and no admin rights needed!
• Compatible with any computer with USB port.
• Automatic time synchronization with the computer.
• Low cost design.

When plugged to a computer’s USB port, the logger appears as a normal USB drive. The temperature logging period is changed by editing a config.txt file. When this file is saved, the logger reads the periodicity (in seconds), synchronizes its clock to the computer’s date and time and starts to flash the LED to indicate it’s ready to log. Once removed from USB, the logging is started by pushing the button (the LED blinks three times). For every temperature measurement, the LED flashes.

via Hackaday

If you’re looking for data logging for your Arduino…

Adafruit Data logging shield for Arduino – v1.0 – Here’s a handy Arduino shield: we’ve had a lot of people looking for a dedicated and well-designed data logging shield. We worked hard to engineer an inexpensive but well-rounded design. Not only is it easy to assemble and customize, it also comes with great documentation and libraries.

You can get going quickly – saving data to files on any FAT16 or FAT32 formatted SD card, to be read by any plotting, spreadsheet or analysis program. We even have a tutorial on how to use two free software programs to plot your data The included Real Time Clock timestamps all your data with the current time, so that you know precisely what happened when!

Please note that this item does not come with an Arduino (you’ll need one to use with the shield), or an SD card. It does come with the RTC battery, however. The kit is un-assembled, You’ll need some basic soldering skills to put it together, but even if you don’t have much experience you can get it done in under 1 hour.

• SD card interface works with FAT16 or FAT32 formatted cards. 3.3v level shifter circuitry prevents damage to your SD card
• Real time clock (RTC) keeps the time going even when the Arduino is unplugged. The battery backup lasts for years
• Included libraries and example code for both SD and RTC mean you can get going quickly
• Prototyping area for soldering connectors, circuitry or sensors.
• Onboard 3.3v regulator is both a reliable reference voltage and also reliably runs SD cards that require a lot of power to run
• An Arduino with a ‘328 chip is pretty much required, you can get an upgrade chip from us if you have an older Arduino (such as NG/Diecimila)

For more information, including libraries, schematics and examples see the data logger shield webpage