Welcome to EnviroDIY, a community for do-it-yourself environmental science and monitoring. EnviroDIY is part of WikiWatershed, an initiative of Stroud Water Research Center designed to help people advance knowledge and stewardship of fresh water.
New to EnviroDIY? Start here


  • Hello,

    I am putting together a micromet station that includes some sdi12 sensors (meter group Terros 21, and Acclima 315H) and some analog thermistors (homebuilt but the same components as the Campbell Sci 107) with a second resistor (24.9K) wired between the return wire and the ground. I have some separate pieces of example code for the SDI12…[Read more]

  • I updated the ADC library and changed the ADC definition on line 77 to the 1115 and that did the trick. 1.5V.   I am assuming that any past data taken in the field with the wrong ADC definition cannot be back calculated. But moving forward we have a working PAR sensor.

    Thank you so much for taking the time to help solve this. Much appreciated.

  • Current board that I am working on in the lab is a 0.5b. But we have run into the same issue with logging/calculating PAR using version 1.0 as well. We are running a mix of 0.5 and 1.0 in the field due to many of the older 0.5’s USB ports failing.


  • Shannon,

    As you suggested, I tested a duplicate of our set up in the lab and used a power supply source set at 1.5V in the aa0 and aa1 ports used to measure PAR on the mayfly. I get 93 mV and 470 umol for PAR. Clearly wrong. It appears the bits are recorded wrong or they are converted to mV incorrectly.  Any thoughts on a next step to…[Read more]

  • Shannon

    I’ll give your suggestions a shot and see if we learn anything.

    Thanks for the quick reply.


  • Hello,

    I am working with a team measuring a host of variables off of mostly SDI12 sensors using both the newest and older Mayflys. We have run into an issue measuring PAR on our Mayfly logger stations. We are using analog Apogee SQ 100 sensors. We get data from the sensors/code, but the output values are about 10x too low. The relevant code is…[Read more]

  • Dan started the topic Vertical SD card in the forum Miscellaneous 4 years, 7 months ago

    Is it possible to buy the vertical micro SD card reader without buying the Mayfly starter kit? Has anyone found an alternate version of this type of reader? I like using small boxes due to the reduced costs, but having the SD card face out is often challenging to work around.

  • Dan became a registered member 4 years, 7 months ago