esphome/esphome/components/sgp40/sgp40.h
Nate Lust 92b85f98e8
Sgp40 fix (#2462)
* Sample from SGP40 sensor at the appropriate interval

The spg40 sensor must be sampled at 1Hz for the VOC index algorithm
to work correctly. This commit introduces a on device timer to
sample correctly seperately from updating the public state of the
component.

* Add missing configuration values for SGP40

The SGP40 component was not printing all of it's configuration in
dump_config, add in the missing store_baseline value.

* Address review comments

* Format according to clang-tidy

* Attempt 2 at clang tidy
2021-10-10 10:33:04 +02:00

95 lines
3.1 KiB
C++

#pragma once
#include "esphome/core/component.h"
#include "esphome/components/sensor/sensor.h"
#include "esphome/components/i2c/i2c.h"
#include "esphome/core/application.h"
#include "esphome/core/preferences.h"
#include "sensirion_voc_algorithm.h"
#include <cmath>
namespace esphome {
namespace sgp40 {
struct SGP40Baselines {
int32_t state0;
int32_t state1;
} PACKED; // NOLINT
// commands and constants
static const uint8_t SGP40_FEATURESET = 0x0020; ///< The required set for this library
static const uint8_t SGP40_CRC8_POLYNOMIAL = 0x31; ///< Seed for SGP40's CRC polynomial
static const uint8_t SGP40_CRC8_INIT = 0xFF; ///< Init value for CRC
static const uint8_t SGP40_WORD_LEN = 2; ///< 2 bytes per word
// Commands
static const uint16_t SGP40_CMD_GET_SERIAL_ID = 0x3682;
static const uint16_t SGP40_CMD_GET_FEATURESET = 0x202f;
static const uint16_t SGP40_CMD_SELF_TEST = 0x280e;
// Shortest time interval of 3H for storing baseline values.
// Prevents wear of the flash because of too many write operations
const uint32_t SHORTEST_BASELINE_STORE_INTERVAL = 10800;
// Store anyway if the baseline difference exceeds the max storage diff value
const uint32_t MAXIMUM_STORAGE_DIFF = 50;
class SGP40Component;
/// This class implements support for the Sensirion sgp40 i2c GAS (VOC) sensors.
class SGP40Component : public PollingComponent, public sensor::Sensor, public i2c::I2CDevice {
public:
void set_humidity_sensor(sensor::Sensor *humidity) { humidity_sensor_ = humidity; }
void set_temperature_sensor(sensor::Sensor *temperature) { temperature_sensor_ = temperature; }
void setup() override;
void update() override;
void update_voc_index();
void dump_config() override;
float get_setup_priority() const override { return setup_priority::DATA; }
void set_store_baseline(bool store_baseline) { store_baseline_ = store_baseline; }
protected:
/// Input sensor for humidity and temperature compensation.
sensor::Sensor *humidity_sensor_{nullptr};
sensor::Sensor *temperature_sensor_{nullptr};
bool write_command_(uint16_t command);
bool read_data_(uint16_t *data, uint8_t len);
int16_t sensirion_init_sensors_();
int16_t sgp40_probe_();
uint8_t sht_crc_(uint8_t data1, uint8_t data2);
uint64_t serial_number_;
uint16_t featureset_;
int32_t measure_voc_index_();
uint8_t generate_crc_(const uint8_t *data, uint8_t datalen);
uint16_t measure_raw_();
ESPPreferenceObject pref_;
int32_t seconds_since_last_store_;
SGP40Baselines baselines_storage_;
VocAlgorithmParams voc_algorithm_params_;
bool self_test_complete_;
bool store_baseline_;
int32_t state0_;
int32_t state1_;
int32_t voc_index_ = 0;
uint8_t samples_read_ = 0;
uint8_t samples_to_stabalize_ = static_cast<int8_t>(VOC_ALGORITHM_INITIAL_BLACKOUT) * 2;
/**
* @brief Request the sensor to perform a self-test, returning the result
*
* @return true: success false:failure
*/
void self_test_();
enum ErrorCode {
COMMUNICATION_FAILED,
MEASUREMENT_INIT_FAILED,
INVALID_ID,
UNSUPPORTED_ID,
UNKNOWN
} error_code_{UNKNOWN};
};
} // namespace sgp40
} // namespace esphome