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102 lines
2.1 KiB
C++
102 lines
2.1 KiB
C++
//
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// FILE: ML8511.cpp
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// AUTHOR: Rob.Tillaart@gmail.com
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// VERSION: 0.1.3
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// PURPOSE: ML8511 - UV sensor - library for Arduino
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//
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// HISTORY:
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// 0.1.0 2020-02-03 initial version
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// 0.1.1 2020-02-17 added _voltPerStep() to support more boards
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// 0.1.2 2020-06-21 refactor; add estimateDUVindex()
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// 0.1.3 2021-01-01 arduino-ci + unit test
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#include "ML8511.h"
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/////////////////////////////////////////////////////
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//
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// PUBLIC
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//
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ML8511::ML8511(uint8_t analogPin, uint8_t enablePin)
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{
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_analogPin = analogPin;
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_voltsPerStep = 5.0/1023;
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_enablePin = enablePin;
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if (enablePin != 0xFF)
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{
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pinMode(_enablePin, OUTPUT);
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digitalWrite(_enablePin, LOW);
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_enabled = false;
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enable();
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}
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else
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{
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_enabled = true;
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}
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};
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float ML8511::getUV(uint8_t energyMode)
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{
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if (!_enabled)
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{
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enable();
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// datasheet page 5 states wait for max 1 millisecond
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uint32_t start = micros();
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while (micros() - start < 1000) yield();
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}
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float voltage = analogRead(_analogPin) * _voltsPerStep;
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if (energyMode == LOW)
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{
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disable();
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}
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// see datasheet - page 4
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// mW/cm2 @ 365 nm
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// @ 25 Celcius
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// formula estimated on graph
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if (voltage <= 1.0)
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{
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return 0.0;
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}
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voltage -= 1.0; // subtract for zero point.
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float mWcm2 = voltage * (15.0 / 1.8);
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return mWcm2;
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}
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// experimental estimate DUV index (not calibrated, USE WITH CARE !!)
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// input is power in mW per cm2
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// weight is pretty high
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float ML8511::estimateDUVindex(float mWcm2)
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{
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float weight = 1.0; // this can be tuned to callibrate
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// convert to mW per m2
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float mWm2 = mWcm2 * 10000;
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// factor to normalize to an 0..10 scale see Wikipedia.
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float factor = 0.04; // 1.0/25;
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return mWm2 * weight * factor;
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};
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void ML8511::setVoltsPerStep(float voltage, uint32_t steps)
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{
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if (steps == 0) return;
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if (voltage > 0.0) _voltsPerStep = voltage / steps;
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}
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void ML8511::enable()
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{
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if (_enablePin != 0xFF) digitalWrite(_enablePin, HIGH);
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_enabled = true;
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};
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void ML8511::disable()
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{
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if (_enablePin != 0xFF) digitalWrite(_enablePin, LOW);
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_enabled = false;
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};
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// -- END OF FILE --
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