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Use this one library to talk to all the I2C devices on your SparkFun Photon Weather Shield
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doc Final Touches Aug 7, 2015


Use this one library to talk to all the built-in I2C devices on your SparkFun Photon Weather Shield


This is a firmware library for SparkFun's Photon Weather Shield.

Photon Battery Shield.

Repository Contents

  • /doc - Additional documentation for the user. These files are ignored by the IDE.
  • /firmware - Source files for the library (.cpp, .h).
  • /firmware/examples - Example sketches for the library (.cpp). Run these from the Particle IDE.
  • spark.json - General library properties for the Particel library manager.

Example Usage

Include the library:

#include "SparkFunMPL3115A2.h" // Include the SparkFun MPL3115A2 library

Then use the Weather object to interact with it. Begin by initializing the IC:

Weather sensor; //Create Instance of Weather Class

The Setup

void setup()
Serial.begin(9600);  // open serial over USB at 9600 baud

// Make sure your Serial Terminal app is closed before powering your device
// Now open your Serial Terminal, and hit any key to continue!
Serial.println("Press any key to begin");
//This line pauses the Serial port until a key is pressed
while(!Serial.available()) Spark.process();

//Initialize the I2C sensors and ping them

/*You can only receive accurate barometric readings or accurate altitiude
readings at a given time, not both at the same time. The following two lines
tell the sensor what mode to use. You could easily write a function that
takes a reading in one mode and then switches to the other mode to grab that
reading, resulting in data that contains both accurate altitude and barometric
readings. For this example, we will only be using the barometer mode. Be sure
to only uncomment one line at a time. */
sensor.setModeBarometer();//Set to Barometer Mode
//sensor.setModeAltimeter();//Set to altimeter Mode

//These are additional MPL3115A2 functions the MUST be called for the sensor to work.
sensor.setOversampleRate(7); // Set Oversample rate
//Call with a rate from 0 to 7. See page 33 for table of ratios.
//Sets the over sample rate. Datasheet calls for 128 but you can set it
//from 1 to 128 samples. The higher the oversample rate the greater
//the time between data samples.

sensor.enableEventFlags(); //Necessary register calls to enble temp, baro and alt

Then you can read various data like this:

// Measure Relative Humidity from the HTU21D or Si7021
humidity = sensor.getRH();

// Measure Temperature from the HTU21D or Si7021
tempf = sensor.getTempF();

//Measure the Barometer temperature in F from the MPL3115A2
baroTemp = sensor.readBaroTempF();

//Measure Pressure from the MPL3115A2
pascals = sensor.readPressure();

//If in altitude mode, you can get a reading in feet with this line:
altf = sensor.readAltitudeFt();

Check out the example files in the examples directory for more guidance.

Recommended Components

License Information

This product is open source!

Please review the file for license information.

If you have any questions or concerns about licensing, please contact

Distributed as-is; no warranty is given.

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