Simple DIY data loggers with no custom PCBs

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We've published a paper about these in Sensors [  } (open access, free pdf download) describing how we use these in caves and underwater, but we also use them on the surface in weather stations for atmospheric conditions, etc. These are stand alone loggers, and are relatively simple devices compared to the Pi-based wireless FIDO's that people have already been talking about in the FarmHack forums. So no text messages, etc. but adding sensors it pretty easy with the support libraries available from Adafruit/Sparkfun.

These loggers and surface housings are relatively easy to assemble, and even without any additional sensors the basic build gives you a temperature logger for less than $20.  Step by step instructions are on the projects website: ( ) and operating code that is easy to modify is available on Github. (use the UNO logger code if you are just starting out with Arduino programming)  The two different environmental housings can be constructed from PVC fittings using basic shop tools, and the 4" housing easily survives full immersion in water to about 3-4 m deep. We frequently use these loggers with MS5803 pressure sensors to monitor water levels.

Dorn's picture

Great contribution!  There is a dynamic Farm IOT conversation that I would love to loop you into.  Check out .  We are working to link the Farm Hack forums into new tools like Discourse and  riot group chat to facilitate exchange of ideas.  Your data loggers would be a great tool to document in the tools section of the site- which will also make it easier to find.  Look forward to next posts!

EdMallon's picture

I'd be happy to put a note about the Pearls in the tools section here. But thought I would check the forum first to see if anyone was actually interested before I did something like that.

I will look around and see what the discussions are like. I'll sign on if there's something I can make a positive contribution towards. Keep in mind that our work is pretty tightly focused on hydrology, rather than Ag.

EdMallon's picture

Just came across this interesting talk on the different growth rates with the same amounts of light spread out over different time periods.

With all the different I2C light sensors out there, LED level controllers like the one he describes at the end of the video would be relatively easy to build with an Arduino. Especially if you could live without the blue-tooth functionality (it: to change the set level for a different crop, you would need reload the logger from your laptop)

EdMallon's picture

A visiting researcher dropped by our humble basement workshop with questions about the physical skill level students would need if they added one of our DIY data loggers to their environmental curriculum. I figured the easiest way to cover that was to simply build one, while they recorded the process.

The result of that 3 hour session is now available on YouTube