mirror of
https://github.com/RobTillaart/Arduino.git
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215 lines
3.2 KiB
C++
215 lines
3.2 KiB
C++
//
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// FILE: MHZCO2.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.1.3
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// PURPOSE: Arduino Library for MHZ series CO2 sensors
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// DATE: 2020-05-05
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// URL: https://github.com/RobTillaart/MHZCO2
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#include "MHZCO2.h"
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MHZCO2::MHZCO2()
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{
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_startTime = millis();
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}
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void MHZCO2::begin(Stream * str)
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{
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_str = str;
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_lastMeasurement = 0;
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_PPM = 0;
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_CO2 = 0;
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_temperature = 0;
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_accuracy = 0;
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_minCO2 = 0;
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}
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uint32_t MHZCO2::uptime()
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{
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return millis() - _startTime;
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}
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void MHZCO2::setPPM(uint16_t PPM)
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{
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_PPM = PPM;
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uint8_t data[9] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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data[8] = PPM >> 8;
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data[7] = PPM & 0xFF;
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data[8] = checksum(data);
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send(data, 9);
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}
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uint16_t MHZCO2::getPPM()
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{
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return _PPM;
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}
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int MHZCO2::measure()
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{
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_lastMeasurement = millis();
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uint8_t data[9] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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data[8] = checksum(data);
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send(data, 9);
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int rv = receive(data);
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// allow partial good data?
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if ((rv == MHZCO2_OK) || (rv == MHZCO2_ERROR_CRC))
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{
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_CO2 = data[2] * 256 + data[3];
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_temperature = data[4] - 40;
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_accuracy = data[5];
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_minCO2 = data[6] * 256 + data[7];
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}
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return rv;
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}
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uint32_t MHZCO2::lastMeasurement()
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{
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return _lastMeasurement;
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}
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int MHZCO2::getCO2()
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{
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return _CO2;
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};
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int MHZCO2::getTemperature()
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{
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return _temperature;
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};
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int MHZCO2::getAccuracy()
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{
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return _accuracy;
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}
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int MHZCO2::getMinCO2()
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{
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return _minCO2;
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};
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void MHZCO2::calibrateZero()
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{
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uint8_t data[9] = {0xFF, 0x01, 0x87, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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data[8] = checksum(data);
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send(data, 9);
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}
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void MHZCO2::calibrateSpan(uint16_t span)
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{
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uint8_t data[9] = {0xFF, 0x01, 0x88, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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data[3] = span >> 8;
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data[4] = span & 0xFF;
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data[8] = checksum(data);
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send(data, 9);
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}
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void MHZCO2::calibrateAuto(bool mode)
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{
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uint8_t data[9] = {0xFF, 0x01, 0x79, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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if (mode) data[3] = 0xA0;
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data[8] = checksum(data);
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send(data, 9);
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}
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/////////////////////////////////////////////////
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//
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// PROTECTED
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//
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void MHZCO2::send(uint8_t * data, uint8_t len)
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{
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_str->write(data, len);
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_str->flush();
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}
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int MHZCO2::receive(uint8_t * answer)
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{
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uint32_t start = millis();
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while (_str->available() == 0)
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{
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if (millis() - start > 1000) return MHZCO2_TIMEOUT;
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}
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for (uint8_t i = 0; i < 9; i++)
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{
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answer[i] = _str->read();
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}
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// verify checksum
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if (answer[8] != checksum(answer)) return MHZCO2_ERROR_CRC;
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return MHZCO2_OK;
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}
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uint8_t MHZCO2::checksum(uint8_t *arr)
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{
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uint8_t sum = 0;
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for (uint8_t i = 1; i < 8; i++)
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{
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sum += arr[i];
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}
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sum = 0xFF - sum;
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return sum + 1;
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}
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/* slightly faster
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uint8_t MHZCO2::checksum(uint8_t *arr)
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{
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uint8_t sum = 0xFF;
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for (uint8_t i = 1; i < 8; i++) sum -= arr[i];
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return sum + 1;
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}
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*/
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/////////////////////////////////////////////////////////
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//
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// DERIVED CLASSES
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//
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MHZ1311A::MHZ1311A() : MHZCO2()
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{
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}
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MHZ19::MHZ19() : MHZCO2()
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{
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}
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MHZ19B::MHZ19B() : MHZCO2()
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{
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}
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MHZ19C::MHZ19C() : MHZCO2()
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{
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}
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MHZ19D::MHZ19D() : MHZCO2()
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{
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}
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MHZ19E::MHZ19E() : MHZCO2()
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{
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}
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// -- END OF FILE --
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