ModularSensors > Examples > simple_logging_LearnEnviroDIY.ino

simple_logging_LearnEnviroDIY.ino example

Learn EnviroDIY Example

This shows the simplest use of a "logger" object. That is, creating an array of variable objects and then creating a logger object that utilizes those variables to update all of the variable results together and save the data to a SD card. The processor then goes to sleep between readings. This example calls on two of the sensors available in this library. The example may be run exactly as written.

This is the example you should use to deploy a logger somewhere where you don't want or have access to a way of streaming live data and you won't want to upload data to the Monitor My Watershed data portal.

Unique Features of the Learn EnviroDIY Example

  • Only logs data to an SD card.
  • Uses a few more sensors than the other simple logging example

To Use this Example:

Prepare and set up PlatformIO

  • Create a new PlatformIO project
  • Replace the contents of the platformio.ini for your new project with the platformio.ini file in the examples/simple_logging_LearnEnviroDIY folder on GitHub.
    • It is important that your PlatformIO configuration has the lib_ldf_mode and build flags set as they are in the example.
    • Without this, the program won't compile.
  • Open simple_logging_LearnEnviroDIY.ino and save it to your computer. Put it into the src directory of your project.
    • Delete main.cpp in that folder.

Set the logger ID

  • Change the "XXXX" in this section of code to the loggerID assigned by Stroud:
// Logger ID, also becomes the prefix for the name of the data file on SD card
const char *LoggerID = "XXXX";


  • Test everything at home before deploying out in the wild!

PlatformIO Configuration

; PlatformIO Project Configuration File
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
; Please visit documentation for the other options and examples

description = ModularSensors example logging data to an SD card from external sensors

monitor_speed = 115200
board = mayfly
platform = atmelavr
framework = arduino
lib_ldf_mode = deep+
lib_ignore =
    Adafruit NeoPixel
    Adafruit GFX Library
    Adafruit SSD1306
    Adafruit ADXL343
    Adafruit STMPE610
    Adafruit TouchScreen
    Adafruit ILI9341
build_flags =
lib_deps =
;  ^^ Use this when working from an official release of the library
;  ^^ Use this when if you want to pull from the develop branch
;  ^^ These are software serial port emulator libraries, you may not need them

The Complete Code

/** =========================================================================
 * @file simple_logging_LearnEnviroDIY.ino
 * @brief A data logging example for the Learn EnviroDIY tutorial.
 * @author Sara Geleskie Damiano <>
 * @copyright (c) 2017-2020 Stroud Water Research Center (SWRC)
 *                          and the EnviroDIY Development Team
 *            This example is published under the BSD-3 license.
 * Build Environment: Visual Studios Code with PlatformIO
 * Hardware Platform: EnviroDIY Mayfly Arduino Datalogger
 * ======================================================================= */

// ==========================================================================
//  Include the libraries required for any data logger
// ==========================================================================
/** Start [includes] */
// The Arduino library is needed for every Arduino program.
#include <Arduino.h>

// EnableInterrupt is used by ModularSensors for external and pin change
// interrupts and must be explicitly included in the main program.
#include <EnableInterrupt.h>

// Include the main header for ModularSensors
#include <ModularSensors.h>
/** End [includes] */

// ==========================================================================
//  Data Logging Options
// ==========================================================================
/** Start [logging_options] */
// The name of this program file
const char* sketchName = "simple_logging.ino";
// Logger ID, also becomes the prefix for the name of the data file on SD card
const char* LoggerID = "XXXXX";
// How frequently (in minutes) to log data
const uint8_t loggingInterval = 5;
// Your logger's timezone.
const int8_t timeZone = -5;  // Eastern Standard Time
// NOTE:  Daylight savings time will not be applied!  Please use standard time!

// Set the input and output pins for the logger
// NOTE:  Use -1 for pins that do not apply
const int32_t serialBaud = 115200;  // Baud rate for debugging
const int8_t  greenLED   = 8;       // Pin for the green LED
const int8_t  redLED     = 9;       // Pin for the red LED
const int8_t  buttonPin  = 21;      // Pin for debugging mode (ie, button pin)
const int8_t  wakePin    = 31;  // MCU interrupt/alarm pin to wake from sleep
// Mayfly 0.x D31 = A7
// Set the wake pin to -1 if you do not want the main processor to sleep.
// In a SAMD system where you are using the built-in rtc, set wakePin to 1
const int8_t sdCardPwrPin   = -1;  // MCU SD card power pin
const int8_t sdCardSSPin    = 12;  // SD card chip select/slave select pin
const int8_t sensorPowerPin = 22;  // MCU pin controlling main sensor power
/** End [logging_options] */

// ==========================================================================
//  Using the Processor as a Sensor
// ==========================================================================
/** Start [processor_sensor] */
#include <sensors/ProcessorStats.h>

// Create the main processor chip "sensor" - for general metadata
const char*    mcuBoardVersion = "v0.5b";
ProcessorStats mcuBoard(mcuBoardVersion);
/** End [processor_sensor] */

// ==========================================================================
//  Maxim DS3231 RTC (Real Time Clock)
// ==========================================================================
/** Start [ds3231] */
#include <sensors/MaximDS3231.h>  // Includes wrapper functions for Maxim DS3231 RTC

// Create a DS3231 sensor object, using this constructor function:
MaximDS3231 ds3231(1);
/** End [ds3231] */

// ==========================================================================
//    Settings for Additional Sensors
// ==========================================================================
// Additional sensors can setup here, similar to the RTC, but only if
//   they have been supported with ModularSensors wrapper functions. See:
// Syntax for the include statement and constructor function for each sensor is
// at
//   or can be copied from the `menu_a_la_carte.ino` example

// ==========================================================================
//  Bosch BME280 Environmental Sensor
// ==========================================================================
/** Start [bme280] */
#include <sensors/BoschBME280.h>

const int8_t I2CPower    = sensorPowerPin;  // Power pin (-1 if unconnected)
uint8_t      BMEi2c_addr = 0x76;
// The BME280 can be addressed either as 0x77 (Adafruit default) or 0x76 (Grove
// default) Either can be physically mofidied for the other address

// Create a Bosch BME280 sensor object
BoschBME280 bme280(I2CPower, BMEi2c_addr);
/** End [bme280] */

// ==========================================================================
//  Maxim DS18 One Wire Temperature Sensor
// ==========================================================================
/** Start [ds18] */
#include <sensors/MaximDS18.h>

// OneWire Address [array of 8 hex characters]
// If only using a single sensor on the OneWire bus, you may omit the address
// DeviceAddress OneWireAddress1 = {0x28, 0xFF, 0xBD, 0xBA, 0x81, 0x16, 0x03,
// 0x0C};
const int8_t OneWirePower = sensorPowerPin;  // Power pin (-1 if unconnected)
const int8_t OneWireBus   = 6;  // OneWire Bus Pin (-1 if unconnected)

// Create a Maxim DS18 sensor objects (use this form for a known address)
// MaximDS18 ds18(OneWireAddress1, OneWirePower, OneWireBus);

// Create a Maxim DS18 sensor object (use this form for a single sensor on bus
// with an unknown address)
MaximDS18 ds18(OneWirePower, OneWireBus);
/** End [ds18] */

// ==========================================================================
//  Creating the Variable Array[s] and Filling with Variable Objects
// ==========================================================================
/** Start [variable_arrays] */
Variable* variableList[] = {
    new ProcessorStats_SampleNumber(&mcuBoard),
    new ProcessorStats_FreeRam(&mcuBoard),
    new ProcessorStats_Battery(&mcuBoard),
    new MaximDS3231_Temp(&ds3231),
    new BoschBME280_Temp(&bme280),
    new BoschBME280_Humidity(&bme280),
    new BoschBME280_Pressure(&bme280),
    new BoschBME280_Altitude(&bme280),
    new MaximDS18_Temp(&ds18)
    // Additional sensor variables can be added here, by copying the syntax
    //   for creating the variable pointer (FORM1) from the
    //   `menu_a_la_carte.ino` example
    // The example code snippets in the wiki are primarily FORM2.
// Count up the number of pointers in the array
int variableCount = sizeof(variableList) / sizeof(variableList[0]);

// Create the VariableArray object
VariableArray varArray;
/** End [variable_arrays] */

// ==========================================================================
//  The Logger Object[s]
// ==========================================================================
/** Start [loggers] */
// Create a logger instance
Logger dataLogger;
/** End [loggers] */

// ==========================================================================
//  Working Functions
// ==========================================================================
/** Start [working_functions] */
// Flashes the LED's on the primary board
void greenredflash(uint8_t numFlash = 4, uint8_t rate = 75) {
    for (uint8_t i = 0; i < numFlash; i++) {
        digitalWrite(greenLED, HIGH);
        digitalWrite(redLED, LOW);
        digitalWrite(greenLED, LOW);
        digitalWrite(redLED, HIGH);
    digitalWrite(redLED, LOW);
/** End [working_functions] */

// ==========================================================================
//  Arduino Setup Function
// ==========================================================================
/** Start [setup] */
void setup() {
    // Start the primary serial connection

    // Print a start-up note to the first serial port
    Serial.print(F("Now running "));
    Serial.print(F(" on Logger "));

    Serial.print(F("Using ModularSensors Library version "));

    // Set up pins for the LED's
    pinMode(greenLED, OUTPUT);
    digitalWrite(greenLED, LOW);
    pinMode(redLED, OUTPUT);
    digitalWrite(redLED, LOW);
    // Blink the LEDs to show the board is on and starting up

    // Set the timezones for the logger/data and the RTC
    // Logging in the given time zone
    // It is STRONGLY RECOMMENDED that you set the RTC to be in UTC (UTC+0)

    // Set information pins
    dataLogger.setLoggerPins(wakePin, sdCardSSPin, sdCardPwrPin, buttonPin,

    // Begin the variable array[s], logger[s], and publisher[s]
    varArray.begin(variableCount, variableList);
    dataLogger.begin(LoggerID, loggingInterval, &varArray);

    // Set up the sensors
    Serial.println(F("Setting up sensors..."));

    // Create the log file, adding the default header to it
    // Do this last so we have the best chance of getting the time correct and
    // all sensor names correct
    dataLogger.createLogFile(true);  // true = write a new header

    // Call the processor sleep
/** End [setup] */

// ==========================================================================
//  Arduino Loop Function
// ==========================================================================
/** Start [loop] */
void loop() {
/** End [loop] */