mirror of https://github.com/arendst/Tasmota.git
278 lines
9.0 KiB
C++
278 lines
9.0 KiB
C++
/*
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xsns_15_mhz.ino - MH-Z19 CO2 sensor support for Sonoff-Tasmota
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Copyright (C) 2017 Theo Arends
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifdef USE_MHZ19_SOFT_SERIAL_OBSOLETE
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/*********************************************************************************************\
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* MH-Z19 - CO2 sensor
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*
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* Based on EspEasy plugin P049 by Dmitry (rel22 ___ inbox.ru)
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**********************************************************************************************
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* Filter usage
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*
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* Select filter usage on low stability readings
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\*********************************************************************************************/
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#include <SoftwareSerial.h>
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SoftwareSerial *SoftSerial;
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enum Mhz19FilterOptions {MHZ19_FILTER_OFF, MHZ19_FILTER_OFF_ALLSAMPLES, MHZ19_FILTER_FAST, MHZ19_FILTER_MEDIUM, MHZ19_FILTER_SLOW};
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#define MHZ19_FILTER_OPTION MHZ19_FILTER_FAST
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/*********************************************************************************************\
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* Source: http://www.winsen-sensor.com/d/files/infrared-gas-sensor/mh-z19b-co2-ver1_0.pdf
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*
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* Automatic Baseline Correction (ABC logic function)
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*
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* ABC logic function refers to that sensor itself do zero point judgment and automatic calibration procedure
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* intelligently after a continuous operation period. The automatic calibration cycle is every 24 hours after powered on.
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*
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* The zero point of automatic calibration is 400ppm.
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*
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* This function is usually suitable for indoor air quality monitor such as offices, schools and homes,
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* not suitable for greenhouse, farm and refrigeratory where this function should be off.
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*
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* Please do zero calibration timely, such as manual or commend calibration.
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\*********************************************************************************************/
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#define MHZ19_ABC_ENABLE 1 // Automatic Baseline Correction (0 = off, 1 = on (default))
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/*********************************************************************************************/
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#define MHZ19_BAUDRATE 9600
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#define MHZ19_READ_TIMEOUT 600 // Must be way less than 1000
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const char kMhz19Types[] PROGMEM = "MHZ19|MHZ19B";
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const byte mhz19_cmnd_read_ppm[9] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};
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const byte mhz19_cmnd_abc_enable[9] = {0xFF, 0x01, 0x79, 0xA0, 0x00, 0x00, 0x00, 0x00, 0xE6};
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const byte mhz19_cmnd_abc_disable[9] = {0xFF, 0x01, 0x79, 0x00, 0x00, 0x00, 0x00, 0x00, 0x86};
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uint8_t mhz19_type = 0;
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uint16_t mhz19_last_ppm = 0;
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uint8_t mhz19_filter = MHZ19_FILTER_OPTION;
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byte mhz19_response[9];
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bool mhz19_abc_enable = MHZ19_ABC_ENABLE;
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bool mhz19_abc_must_apply = false;
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char mhz19_types[7];
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bool Mhz19CheckAndApplyFilter(uint16_t ppm, uint8_t s)
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{
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if (1 == s) {
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return false; // S==1 => "A" version sensor bootup, do not use values.
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}
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if (mhz19_last_ppm < 400 || mhz19_last_ppm > 5000) {
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// Prevent unrealistic values during start-up with filtering enabled.
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// Just assume the entered value is correct.
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mhz19_last_ppm = ppm;
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return true;
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}
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int32_t difference = ppm - mhz19_last_ppm;
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if (s > 0 && s < 64 && mhz19_filter != MHZ19_FILTER_OFF) {
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// Not the "B" version of the sensor, S value is used.
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// S==0 => "B" version, else "A" version
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// The S value is an indication of the stability of the reading.
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// S == 64 represents a stable reading and any lower value indicates (unusual) fast change.
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// Now we increase the delay filter for low values of S and increase response time when the
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// value is more stable.
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// This will make the reading useful in more turbulent environments,
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// where the sensor would report more rapid change of measured values.
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difference = difference * s;
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difference /= 64;
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}
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switch (mhz19_filter) {
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case MHZ19_FILTER_OFF: {
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if (s != 0 && s != 64) {
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return false;
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}
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break;
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}
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// #Samples to reach >= 75% of step response
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case MHZ19_FILTER_OFF_ALLSAMPLES:
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break; // No Delay
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case MHZ19_FILTER_FAST:
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difference /= 2;
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break; // Delay: 2 samples
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case MHZ19_FILTER_MEDIUM:
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difference /= 4;
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break; // Delay: 5 samples
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case MHZ19_FILTER_SLOW:
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difference /= 8;
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break; // Delay: 11 samples
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}
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mhz19_last_ppm = static_cast<uint16_t>(mhz19_last_ppm + difference);
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return true;
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}
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bool Mhz19Read(uint16_t &p, float &t)
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{
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bool status = false;
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p = 0;
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t = NAN;
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if (mhz19_type)
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{
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SoftSerial->flush();
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if (SoftSerial->write(mhz19_cmnd_read_ppm, 9) != 9) {
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return false; // Unable to send 9 bytes
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}
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memset(mhz19_response, 0, sizeof(mhz19_response));
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uint32_t start = millis();
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uint8_t counter = 0;
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while (((millis() - start) < MHZ19_READ_TIMEOUT) && (counter < 9)) {
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if (SoftSerial->available() > 0) {
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mhz19_response[counter++] = SoftSerial->read();
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} else {
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delay(10);
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}
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}
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if (counter < 9){
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return false; // Timeout while trying to read
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}
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byte crc = 0;
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for (uint8_t i = 1; i < 8; i++) {
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crc += mhz19_response[i];
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}
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crc = 255 - crc;
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crc++;
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/*
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// Test data
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mhz19_response[0] = 0xFF;
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mhz19_response[1] = 0x86;
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mhz19_response[2] = 0x12;
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mhz19_response[3] = 0x86;
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mhz19_response[4] = 64;
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// mhz19_response[5] = 32;
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mhz19_response[8] = crc;
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*/
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if (0xFF == mhz19_response[0] && 0x86 == mhz19_response[1] && mhz19_response[8] == crc) {
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uint16_t u = (mhz19_response[6] << 8) | mhz19_response[7];
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if (15000 == u) { // During (and only ever at) sensor boot, 'u' is reported as 15000
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if (!mhz19_abc_enable) {
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// After bootup of the sensor the ABC will be enabled.
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// Thus only actively disable after bootup.
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mhz19_abc_must_apply = true;
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}
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} else {
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uint16_t ppm = (mhz19_response[2] << 8) | mhz19_response[3];
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t = ConvertTemp((float)mhz19_response[4] - 40);
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uint8_t s = mhz19_response[5];
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if (s) {
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mhz19_type = 1;
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} else {
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mhz19_type = 2;
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}
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if (Mhz19CheckAndApplyFilter(ppm, s)) {
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p = mhz19_last_ppm;
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if (0 == s || 64 == s) { // Reading is stable.
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if (mhz19_abc_must_apply) {
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mhz19_abc_must_apply = false;
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if (mhz19_abc_enable) {
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SoftSerial->write(mhz19_cmnd_abc_enable, 9); // Sent sensor ABC Enable
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} else {
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SoftSerial->write(mhz19_cmnd_abc_disable, 9); // Sent sensor ABC Disable
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}
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}
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}
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status = true;
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}
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}
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}
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}
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return status;
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}
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void Mhz19Init()
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{
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SoftSerial = new SoftwareSerial(pin[GPIO_MHZ_RXD], pin[GPIO_MHZ_TXD]);
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SoftSerial->begin(9600);
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mhz19_type = 1;
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}
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#ifdef USE_WEBSERVER
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const char HTTP_SNS_CO2[] PROGMEM =
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"%s{s}%s " D_CO2 "{m}%d " D_UNIT_PPM "{e}"; // {s} = <tr><th>, {m} = </th><td>, {e} = </td></tr>
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#endif // USE_WEBSERVER
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void Mhz19Show(boolean json)
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{
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uint16_t co2;
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float t;
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if (Mhz19Read(co2, t)) {
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char temperature[10];
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dtostrfd(t, Settings.flag2.temperature_resolution, temperature);
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GetTextIndexed(mhz19_types, sizeof(mhz19_types), mhz19_type -1, kMhz19Types);
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if (json) {
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snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_CO2 "\":%d,\"" D_TEMPERATURE "\":%s}"), mqtt_data, mhz19_types, co2, temperature);
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#ifdef USE_DOMOTICZ
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DomoticzSensor(DZ_COUNT, co2);
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#endif // USE_DOMOTICZ
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#ifdef USE_WEBSERVER
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} else {
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snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_CO2, mqtt_data, mhz19_types, co2);
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snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_TEMP, mqtt_data, mhz19_types, temperature, TempUnit());
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#endif // USE_WEBSERVER
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}
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}
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}
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/*********************************************************************************************\
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* Interface
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\*********************************************************************************************/
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#define XSNS_15
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boolean Xsns15(byte function)
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{
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boolean result = false;
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if ((pin[GPIO_MHZ_RXD] < 99) && (pin[GPIO_MHZ_TXD] < 99)) {
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switch (function) {
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case FUNC_XSNS_INIT:
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Mhz19Init();
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break;
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case FUNC_XSNS_PREP:
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// Mhz19Prep();
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break;
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case FUNC_XSNS_JSON_APPEND:
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Mhz19Show(1);
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break;
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#ifdef USE_WEBSERVER
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case FUNC_XSNS_WEB:
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Mhz19Show(0);
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// Mhz19Prep();
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break;
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#endif // USE_WEBSERVER
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}
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}
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return result;
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}
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#endif // USE_MHZ19_SOFT_SERIAL_OBSOLETE
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