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234 lines
6.3 KiB
234 lines
6.3 KiB
// -----------------------------------------------------------------------------
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// SenseAir S8 CO2 Sensor
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// Uses SoftwareSerial library
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// Contribution by Yonsm Guo
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// -----------------------------------------------------------------------------
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#if SENSOR_SUPPORT && SENSEAIR_SUPPORT
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#pragma once
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#include <Arduino.h>
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#include <SoftwareSerial.h>
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#include "BaseSensor.h"
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// SenseAir sensor utils
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class SenseAir
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{
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protected:
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SoftwareSerial *_serial; // Should initialized by child class
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public:
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int sendCommand(byte command[]) {
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byte recv_buf[7] = {0xff};
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byte data_buf[2] = {0xff};
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long value = -1;
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_serial->write(command, 8); //Send the byte array
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delay(50);
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// Read answer from sensor
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int ByteCounter = 0;
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while(_serial->available()) {
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recv_buf[ByteCounter] = _serial->read();
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ByteCounter++;
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}
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data_buf[0] = recv_buf[3];
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data_buf[1] = recv_buf[4];
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value = (data_buf[0] << 8) | (data_buf[1]);
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return value;
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}
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int readCo2(void) {
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int co2 = 0;
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byte frame[8] = {0};
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buildFrame(0xFE, 0x04, 0x03, 1, frame);
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co2 = sendCommand(frame);
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return co2;
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}
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private:
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// Compute the MODBUS RTU CRC
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static unsigned int modRTU_CRC(byte buf[], int len, byte checkSum[2]) {
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unsigned int crc = 0xFFFF;
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for (int pos = 0; pos < len; pos++) {
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crc ^= (unsigned int)buf[pos]; // XOR byte into least sig. byte of crc
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for (int i = 8; i != 0; i--) { // Loop over each bit
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if ((crc & 0x0001) != 0) { // If the LSB is set
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crc >>= 1; // Shift right and XOR 0xA001
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crc ^= 0xA001;
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}
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else // Else LSB is not set
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crc >>= 1; // Just shift right
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}
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}
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// Note, this number has low and high bytes swapped, so use it accordingly (or swap bytes)
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checkSum[1] = (byte)((crc >> 8) & 0xFF);
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checkSum[0] = (byte)(crc & 0xFF);
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return crc;
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}
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static int getBitOfInt(int reg, int pos) {
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// Create a mask
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int mask = 0x01 << pos;
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// Mask the status register
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int masked_register = mask & reg;
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// Shift the result of masked register back to position 0
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int result = masked_register >> pos;
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return result;
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}
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static void buildFrame(byte slaveAddress,
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byte functionCode,
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short startAddress,
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short numberOfRegisters,
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byte frame[8]) {
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frame[0] = slaveAddress;
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frame[1] = functionCode;
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frame[2] = (byte)(startAddress >> 8);
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frame[3] = (byte)(startAddress);
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frame[4] = (byte)(numberOfRegisters >> 8);
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frame[5] = (byte)(numberOfRegisters);
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// CRC-calculation
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byte checkSum[2] = {0};
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modRTU_CRC(frame, 6, checkSum);
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frame[6] = checkSum[0];
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frame[7] = checkSum[1];
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}
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};
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//
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class SenseAirSensor : public BaseSensor, SenseAir {
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public:
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// ---------------------------------------------------------------------
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// Public
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// ---------------------------------------------------------------------
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SenseAirSensor() {
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_count = 1;
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_co2 = 0;
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_lastCo2 = 0;
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_serial = NULL;
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_sensor_id = SENSOR_SENSEAIR_ID;
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}
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~SenseAirSensor() {
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if (_serial) delete _serial;
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_serial = NULL;
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}
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void setRX(unsigned char pin_rx) {
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if (_pin_rx == pin_rx) return;
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_pin_rx = pin_rx;
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_dirty = true;
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}
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void setTX(unsigned char pin_tx) {
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if (_pin_tx == pin_tx) return;
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_pin_tx = pin_tx;
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_dirty = true;
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}
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// ---------------------------------------------------------------------
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unsigned char getRX() {
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return _pin_rx;
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}
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unsigned char getTX() {
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return _pin_tx;
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}
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// ---------------------------------------------------------------------
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// Sensor API
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// ---------------------------------------------------------------------
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// Initialization method, must be idempotent
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void begin() {
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if (!_dirty) return;
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if (_serial) delete _serial;
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_serial = new SoftwareSerial(_pin_rx, _pin_tx, false, 64);
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_serial->enableIntTx(false);
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_serial->begin(9600);
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_serial->enableRx(true);
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_startTime = 0;
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_ready = true;
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_dirty = false;
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}
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// Descriptive name of the sensor
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String description() {
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char buffer[28];
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snprintf(buffer, sizeof(buffer), "SenseAir S8 @ SwSerial(%u,%u)", _pin_rx, _pin_tx);
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return String(buffer);
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}
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// Descriptive name of the slot # index
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String slot(unsigned char index) {
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return description();
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}
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// Address of the sensor (it could be the GPIO or I2C address)
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String address(unsigned char index) {
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char buffer[6];
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snprintf(buffer, sizeof(buffer), "%u:%u", _pin_rx, _pin_tx);
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return String(buffer);
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}
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// Type for slot # index
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unsigned char type(unsigned char index) {
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return MAGNITUDE_CO2;
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}
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void pre() {
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if (millis() - _startTime < 20000) {
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_error = SENSOR_ERROR_WARM_UP;
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return;
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}
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unsigned int co2 = readCo2();
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if (co2 >= 5000 || co2 < 100)
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{
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_co2 = _lastCo2;
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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}
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else
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{
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_co2 = (co2 > _lastCo2 + 2000) ? _lastCo2 : co2;
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_lastCo2 = co2;
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_error = SENSOR_ERROR_OK;
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}
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}
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// Current value for slot # index
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double value(unsigned char index) {
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return _co2;
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}
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protected:
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unsigned int _pin_rx;
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unsigned int _pin_tx;
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unsigned long _startTime;
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unsigned int _co2;
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unsigned int _lastCo2;
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};
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#endif // SENSOR_SUPPORT && SENSEAIR_SUPPORT
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