SparkFun_SCD30_Arduino_Library.h

/*
  This is a library written for the SCD30
  SparkFun sells these at its website: www.sparkfun.com
  Do you like this library? Help support SparkFun. Buy a board!
  https://www.sparkfun.com/products/14751

  Written by Nathan Seidle @ SparkFun Electronics, May 22nd, 2018

  The SCD30 measures CO2 with accuracy of +/- 30ppm.

  This library handles the initialization of the SCD30 and outputs
  CO2 levels, relative humidty, and temperature.

  https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library

  Development environment specifics:
  Arduino IDE 1.8.5

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __SparkFun_SCD30_ARDUINO_LIBARARY_H__
#define __SparkFun_SCD30_ARDUINO_LIBARARY_H__

#include "Arduino.h"
#include <Wire.h>

//The default I2C address for the SCD30 is 0x61.
#define SCD30_ADDRESS 0x61

//Available commands

#define COMMAND_CONTINUOUS_MEASUREMENT 0x0010
#define COMMAND_SET_MEASUREMENT_INTERVAL 0x4600
#define COMMAND_GET_DATA_READY 0x0202
#define COMMAND_READ_MEASUREMENT 0x0300
#define COMMAND_AUTOMATIC_SELF_CALIBRATION 0x5306
#define COMMAND_SET_FORCED_RECALIBRATION_FACTOR 0x5204
#define COMMAND_SET_TEMPERATURE_OFFSET 0x5403
#define COMMAND_SET_ALTITUDE_COMPENSATION 0x5102

class SCD30
{
public:
	SCD30(void);
  
	bool begin(bool autoCalibrate) { return begin(Wire, autoCalibrate); }
	bool begin(TwoWire &wirePort = Wire, bool autoCalibrate=true); //By default use Wire port

	bool beginMeasuring(uint16_t pressureOffset);
	bool beginMeasuring(void);

	uint16_t getCO2(void);
	float getHumidity(void);
	float getTemperature(void);
	float getTemperatureOffset(void);

	bool setMeasurementInterval(uint16_t interval);
	bool setAmbientPressure(uint16_t pressure_mbar);
	bool setAltitudeCompensation(uint16_t altitude);
	bool setAutoSelfCalibration(bool enable);
	bool setForcedRecalibrationFactor(uint16_t concentration);
	bool setTemperatureOffset(float tempOffset);

	bool dataAvailable();
	bool readMeasurement();

	bool sendCommand(uint16_t command, uint16_t arguments);
	bool sendCommand(uint16_t command);

	uint16_t readRegister(uint16_t registerAddress);

	uint8_t computeCRC8(uint8_t data[], uint8_t len);

private:
	//Variables
	TwoWire *_i2cPort; //The generic connection to user's chosen I2C hardware

	//Global main datums
	float co2 = 0;
	float temperature = 0;
	float humidity = 0;

	//These track the staleness of the current data
	//This allows us to avoid calling readMeasurement() every time individual datums are requested
	bool co2HasBeenReported = true;
	bool humidityHasBeenReported = true;
	bool temperatureHasBeenReported = true;
};
#endif