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/*
* Copyright 2021 Birte Kristina Friesel
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#ifndef VEML6075_H
#define VEML6075_H
#include <stdint.h>
/**
* Driver for VEML6075 UV Sensor.
*/
class VEML6075 {
private:
VEML6075(const VEML6075 ©);
unsigned char const address;
unsigned char txbuf[2];
unsigned char rxbuf[2];
/*
* Calibration data from <https://cdn.sparkfun.com/assets/3/9/d/4/1/designingveml6075.pdf>,
* used to remove the visible and infrared response from UVA / UVB readings.
*/
const float uva_a_coef = 2.22;
const float uva_b_coef = 1.33;
const float uvb_c_coef = 2.95;
const float uvb_d_coef = 1.74;
/*
* Datasheet values for counts → µW/cm² conversion at 50ms integration time.
* I'm not sure whether this is before or after adjusting for visible and IR response.
*/
const float uva_counts_per_uwcm2 = 0.93;
const float uvb_counts_per_uwcm2 = 2.1;
/*
* Responsivity for UV Index calculation from <https://cdn.sparkfun.com/assets/3/9/d/4/1/designingveml6075.pdf>.
* Used after visible/IR compensation.
*/
const float uva_uvi_response = 0.001461;
const float uvb_uvi_response = 0.002591;
bool readUVCounts(float *uva, float *uvb);
public:
/**
* Create a new VEML6075 object for the specified I2C address.
* This is a no-op; the sensor is not initialized. In its default
* configuration, it takes a light reading every 800ms and uses
* auto-ranging to select a suitable measurement range.
*
* @param addr I2C address of light sensor, default 0x4a
*/
VEML6075(unsigned char const addr = 0x10) : address(addr) {}
/**
* Initialize VEML6075 to power on, normal mode, normal dynamic, 50ms
* integration time.
* @return true if initialization was successful.
*/
bool init();
/**
* Read UVA/UVB irradiance.
* @param uva UVA irradiance [µW/cm²]
* @param uvb UVB irradiance [µW/cm²]
* @return true if readout was successful.
*/
bool readUV(float *uva, float *uvb);
/**
* Read UVA/UVB Index. 0 is no UV, higher values indicate increased UV exposure.
* The overall UV index is mean(UVA Index, UV Index) == (UVA Index + UVB Index)/2.
* @param uva UVA Index
* @param uvb UVB Index
* @return true if readout was successful.
*/
bool readUVI(float *uva, float *uvb);
};
extern VEML6075 veml6075;
#endif
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