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The EnviroDIY ModularSensors Library

If you're new to EnviroDIY, I suggest you check out the Just Getting Started section of the documentation!

This Arduino library gives environmental sensors a common interface of functions for use with Arduino-compatible dataloggers, such as the EnviroDIY Mayfly. The ModularSensors library is specifically designed to support wireless, solar-powered environmental data logging applications, that is, to:

  • Retrieve data from many physical sensors;
  • Save that data to a SD memory card;
  • Transmit that data wirelessly to a web server; and
  • Put the processor, sensors and all other peripherals to sleep between readings to conserve power.

The ModularSensors library coordinates these tasks by "wrapping" native sensor libraries into a common interface of functions and returns. These wrapper functions serve to harmonize and simplify the process of iterating through and logging data from a diverse set of sensors and variables. Using the common sensor and variable interface, the library attempts to optimize measurement timing as much as possible to reduce logger "on-time" and power consumption.

Although this library was written primarily for the EnviroDIY Mayfly data logger board, it is also designed to be compatible with a variety of other Arduino-based boards as well.

There is extensive documentation available in the ModularSensors github pages including details of the class structures and example code.

Supported Sensors

For some generalized information about attaching sensors to an Arduino style board, see the Sensor Notes page.

Data Endpoints

Within ModularSensors, the "dataPublisher" objects add the functionality to send data to remote web services. The currently supported services are the Monitor My Watershed data portal, ThingSpeak, and the Ubidots IoT platform.

Supported Cellular/Wifi Modules:

For information common to all modems and for tables of the proper class, baud rate, and pins to uses, see the Modem Notes page.


Open an issue to suggest and discuss potential changes/additions. Feel free to open issues about any bugs you find or any sensors you would like to have added.

If you would like to directly help with the coding development of the library, there are some tips here on how to set up PlatformIO so you can fork the library and test programs while in the library repo. Please take time to familiarize yourself with the terminology, classes and data structures this library uses. This library is built to fully take advantage of Objecting Oriented Programing (OOP) approaches and is larger and more complicated than many Arduino libraries. There is extensive documentation on our github pages and an enormous number of comments and debugging printouts in the code itself to help you get going.


Software sketches and code are released under the BSD 3-Clause License -- See file for details.

Documentation is licensed as Creative Commons Attribution-ShareAlike 4.0 (CC-BY-SA) copyright.

Hardware designs shared are released, unless otherwise indicated, under the CERN Open Hardware License 1.2 (CERN_OHL).


EnviroDIY™ is presented by the Stroud Water Research Center, with contributions from a community of enthusiasts sharing do-it-yourself ideas for environmental science and monitoring.

Sara Damiano is the primary developer of the EnviroDIY ModularSensors library, with input from many other contributors.

This project has benefited from the support from the following funders:

  • William Penn Foundation
  • US Environmental Protection Agency (EPA)
  • National Science Foundation, awards EAR-0724971, EAR-1331856, ACI-1339834
  • Stroud Water Research Center endowment