Add support for SGP41 (#3382)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/sgp4x/sensor.py

@@ -0,0 +1,144 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import i2c, sensor, sensirion_common
+from esphome.const import (
+    CONF_ID,
+    CONF_STORE_BASELINE,
+    CONF_TEMPERATURE_SOURCE,
+    ICON_RADIATOR,
+    DEVICE_CLASS_NITROUS_OXIDE,
+    DEVICE_CLASS_VOLATILE_ORGANIC_COMPOUNDS,
+    STATE_CLASS_MEASUREMENT,
+)
+
+DEPENDENCIES = ["i2c"]
+AUTO_LOAD = ["sensirion_common"]
+CODEOWNERS = ["@SenexCrenshaw", "@martgras"]
+
+sgp4x_ns = cg.esphome_ns.namespace("sgp4x")
+SGP4xComponent = sgp4x_ns.class_(
+    "SGP4xComponent",
+    sensor.Sensor,
+    cg.PollingComponent,
+    sensirion_common.SensirionI2CDevice,
+)
+
+CONF_ALGORITHM_TUNING = "algorithm_tuning"
+CONF_COMPENSATION = "compensation"
+CONF_GAIN_FACTOR = "gain_factor"
+CONF_GATING_MAX_DURATION_MINUTES = "gating_max_duration_minutes"
+CONF_HUMIDITY_SOURCE = "humidity_source"
+CONF_INDEX_OFFSET = "index_offset"
+CONF_LEARNING_TIME_GAIN_HOURS = "learning_time_gain_hours"
+CONF_LEARNING_TIME_OFFSET_HOURS = "learning_time_offset_hours"
+CONF_NOX = "nox"
+CONF_STD_INITIAL = "std_initial"
+CONF_VOC = "voc"
+CONF_VOC_BASELINE = "voc_baseline"
+
+
+def validate_sensors(config):
+    if CONF_VOC not in config and CONF_NOX not in config:
+        raise cv.Invalid(
+            f"At least one sensor is required. Define {CONF_VOC} and/or {CONF_NOX}"
+        )
+    return config
+
+
+GAS_SENSOR = cv.Schema(
+    {
+        cv.Optional(CONF_ALGORITHM_TUNING): cv.Schema(
+            {
+                cv.Optional(CONF_INDEX_OFFSET, default=100): cv.int_,
+                cv.Optional(CONF_LEARNING_TIME_OFFSET_HOURS, default=12): cv.int_,
+                cv.Optional(CONF_LEARNING_TIME_GAIN_HOURS, default=12): cv.int_,
+                cv.Optional(CONF_GATING_MAX_DURATION_MINUTES, default=720): cv.int_,
+                cv.Optional(CONF_STD_INITIAL, default=50): cv.int_,
+                cv.Optional(CONF_GAIN_FACTOR, default=230): cv.int_,
+            }
+        )
+    }
+)
+
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(SGP4xComponent),
+            cv.Optional(CONF_VOC): sensor.sensor_schema(
+                icon=ICON_RADIATOR,
+                accuracy_decimals=0,
+                device_class=DEVICE_CLASS_VOLATILE_ORGANIC_COMPOUNDS,
+                state_class=STATE_CLASS_MEASUREMENT,
+            ).extend(GAS_SENSOR),
+            cv.Optional(CONF_NOX): sensor.sensor_schema(
+                icon=ICON_RADIATOR,
+                accuracy_decimals=0,
+                device_class=DEVICE_CLASS_NITROUS_OXIDE,
+                state_class=STATE_CLASS_MEASUREMENT,
+            ).extend(GAS_SENSOR),
+            cv.Optional(CONF_STORE_BASELINE, default=True): cv.boolean,
+            cv.Optional(CONF_VOC_BASELINE): cv.hex_uint16_t,
+            cv.Optional(CONF_COMPENSATION): cv.Schema(
+                {
+                    cv.Required(CONF_HUMIDITY_SOURCE): cv.use_id(sensor.Sensor),
+                    cv.Required(CONF_TEMPERATURE_SOURCE): cv.use_id(sensor.Sensor),
+                },
+            ),
+        }
+    )
+    .extend(cv.polling_component_schema("60s"))
+    .extend(i2c.i2c_device_schema(0x59)),
+    validate_sensors,
+)
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    await i2c.register_i2c_device(var, config)
+
+    if CONF_COMPENSATION in config:
+        compensation_config = config[CONF_COMPENSATION]
+        sens = await cg.get_variable(compensation_config[CONF_HUMIDITY_SOURCE])
+        cg.add(var.set_humidity_sensor(sens))
+        sens = await cg.get_variable(compensation_config[CONF_TEMPERATURE_SOURCE])
+        cg.add(var.set_temperature_sensor(sens))
+
+    cg.add(var.set_store_baseline(config[CONF_STORE_BASELINE]))
+
+    if CONF_VOC_BASELINE in config:
+        cg.add(var.set_voc_baseline(CONF_VOC_BASELINE))
+
+    if CONF_VOC in config:
+        sens = await sensor.new_sensor(config[CONF_VOC])
+        cg.add(var.set_voc_sensor(sens))
+        if CONF_ALGORITHM_TUNING in config[CONF_VOC]:
+            cfg = config[CONF_VOC][CONF_ALGORITHM_TUNING]
+            cg.add(
+                var.set_voc_algorithm_tuning(
+                    cfg[CONF_INDEX_OFFSET],
+                    cfg[CONF_LEARNING_TIME_OFFSET_HOURS],
+                    cfg[CONF_LEARNING_TIME_GAIN_HOURS],
+                    cfg[CONF_GATING_MAX_DURATION_MINUTES],
+                    cfg[CONF_STD_INITIAL],
+                    cfg[CONF_GAIN_FACTOR],
+                )
+            )
+
+    if CONF_NOX in config:
+        sens = await sensor.new_sensor(config[CONF_NOX])
+        cg.add(var.set_nox_sensor(sens))
+        if CONF_ALGORITHM_TUNING in config[CONF_NOX]:
+            cfg = config[CONF_NOX][CONF_ALGORITHM_TUNING]
+            cg.add(
+                var.set_nox_algorithm_tuning(
+                    cfg[CONF_INDEX_OFFSET],
+                    cfg[CONF_LEARNING_TIME_OFFSET_HOURS],
+                    cfg[CONF_LEARNING_TIME_GAIN_HOURS],
+                    cfg[CONF_GATING_MAX_DURATION_MINUTES],
+                    cfg[CONF_GAIN_FACTOR],
+                )
+            )
+    cg.add_library(
+        None, None, "https://github.com/Sensirion/arduino-gas-index-algorithm.git"
+    )

esphome/components/sgp4x/sgp4x.cpp

@@ -0,0 +1,343 @@
+#include "sgp4x.h"
+#include "esphome/core/log.h"
+#include "esphome/core/hal.h"
+#include <cinttypes>
+
+namespace esphome {
+namespace sgp4x {
+
+static const char *const TAG = "sgp4x";
+
+void SGP4xComponent::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up SGP4x...");
+
+  // Serial Number identification
+  uint16_t raw_serial_number[3];
+  if (!this->get_register(SGP4X_CMD_GET_SERIAL_ID, raw_serial_number, 3, 1)) {
+    ESP_LOGE(TAG, "Failed to read serial number");
+    this->error_code_ = SERIAL_NUMBER_IDENTIFICATION_FAILED;
+    this->mark_failed();
+    return;
+  }
+  this->serial_number_ = (uint64_t(raw_serial_number[0]) << 24) | (uint64_t(raw_serial_number[1]) << 16) |
+                         (uint64_t(raw_serial_number[2]));
+  ESP_LOGD(TAG, "Serial Number: %" PRIu64, this->serial_number_);
+
+  // Featureset identification for future use
+  uint16_t raw_featureset;
+  if (!this->get_register(SGP4X_CMD_GET_FEATURESET, raw_featureset, 1)) {
+    ESP_LOGD(TAG, "raw_featureset write_command_ failed");
+    this->mark_failed();
+    return;
+  }
+  this->featureset_ = raw_featureset;
+  if ((this->featureset_ & 0x1FF) == SGP40_FEATURESET) {
+    sgp_type_ = SGP40;
+    self_test_time_ = SPG40_SELFTEST_TIME;
+    measure_time_ = SGP40_MEASURE_TIME;
+    if (this->nox_sensor_) {
+      ESP_LOGE(TAG, "Measuring NOx requires a SGP41 sensor but a SGP40 sensor is detected");
+      // disable the sensor
+      this->nox_sensor_->set_disabled_by_default(true);
+      // make sure it's not visiable in HA
+      this->nox_sensor_->set_internal(true);
+      this->nox_sensor_->state = NAN;
+      // remove pointer to sensor
+      this->nox_sensor_ = nullptr;
+    }
+  } else {
+    if ((this->featureset_ & 0x1FF) == SGP41_FEATURESET) {
+      sgp_type_ = SGP41;
+      self_test_time_ = SPG41_SELFTEST_TIME;
+      measure_time_ = SGP41_MEASURE_TIME;
+    } else {
+      ESP_LOGD(TAG, "Product feature set failed 0x%0X , expecting 0x%0X", uint16_t(this->featureset_ & 0x1FF),
+               SGP40_FEATURESET);
+      this->mark_failed();
+      return;
+    }
+  }
+
+  ESP_LOGD(TAG, "Product version: 0x%0X", uint16_t(this->featureset_ & 0x1FF));
+
+  if (this->store_baseline_) {
+    // Hash with compilation time
+    // This ensures the baseline storage is cleared after OTA
+    uint32_t hash = fnv1_hash(App.get_compilation_time());
+    this->pref_ = global_preferences->make_preference<SGP4xBaselines>(hash, true);
+
+    if (this->pref_.load(&this->voc_baselines_storage_)) {
+      this->voc_state0_ = this->voc_baselines_storage_.state0;
+      this->voc_state1_ = this->voc_baselines_storage_.state1;
+      ESP_LOGI(TAG, "Loaded VOC baseline state0: 0x%04X, state1: 0x%04X", this->voc_baselines_storage_.state0,
+               voc_baselines_storage_.state1);
+    }
+
+    // Initialize storage timestamp
+    this->seconds_since_last_store_ = 0;
+
+    if (this->voc_baselines_storage_.state0 > 0 && this->voc_baselines_storage_.state1 > 0) {
+      ESP_LOGI(TAG, "Setting VOC baseline from save state0: 0x%04X, state1: 0x%04X",
+               this->voc_baselines_storage_.state0, voc_baselines_storage_.state1);
+      voc_algorithm_.set_states(this->voc_baselines_storage_.state0, this->voc_baselines_storage_.state1);
+    }
+  }
+  if (this->voc_sensor_ && this->voc_tuning_params_.has_value()) {
+    voc_algorithm_.set_tuning_parameters(
+        voc_tuning_params_.value().index_offset, voc_tuning_params_.value().learning_time_offset_hours,
+        voc_tuning_params_.value().learning_time_gain_hours, voc_tuning_params_.value().gating_max_duration_minutes,
+        voc_tuning_params_.value().std_initial, voc_tuning_params_.value().gain_factor);
+  }
+
+  if (this->nox_sensor_ && this->nox_tuning_params_.has_value()) {
+    nox_algorithm_.set_tuning_parameters(
+        nox_tuning_params_.value().index_offset, nox_tuning_params_.value().learning_time_offset_hours,
+        nox_tuning_params_.value().learning_time_gain_hours, nox_tuning_params_.value().gating_max_duration_minutes,
+        nox_tuning_params_.value().std_initial, nox_tuning_params_.value().gain_factor);
+  }
+
+  this->self_test_();
+
+  /* The official spec for this sensor at
+  https://sensirion.com/media/documents/296373BB/6203C5DF/Sensirion_Gas_Sensors_Datasheet_SGP40.pdf indicates this
+  sensor should be driven at 1Hz. Comments from the developers at:
+  https://github.com/Sensirion/embedded-sgp/issues/136 indicate the algorithm should be a bit resilient to slight
+  timing variations so the software timer should be accurate enough for this.
+
+  This block starts sampling from the sensor at 1Hz, and is done seperately from the call
+  to the update method. This seperation is to support getting accurate measurements but
+  limit the amount of communication done over wifi for power consumption or to keep the
+  number of records reported from being overwhelming.
+  */
+  ESP_LOGD(TAG, "Component requires sampling of 1Hz, setting up background sampler");
+  this->set_interval(1000, [this]() { this->update_gas_indices(); });
+}
+
+void SGP4xComponent::self_test_() {
+  ESP_LOGD(TAG, "Self-test started");
+  if (!this->write_command(SGP4X_CMD_SELF_TEST)) {
+    this->error_code_ = COMMUNICATION_FAILED;
+    ESP_LOGD(TAG, "Self-test communication failed");
+    this->mark_failed();
+  }
+
+  this->set_timeout(self_test_time_, [this]() {
+    uint16_t reply;
+    if (!this->read_data(reply)) {
+      this->error_code_ = SELF_TEST_FAILED;
+      ESP_LOGD(TAG, "Self-test read_data_ failed");
+      this->mark_failed();
+      return;
+    }
+
+    if (reply == 0xD400) {
+      this->self_test_complete_ = true;
+      ESP_LOGD(TAG, "Self-test completed");
+      return;
+    } else {
+      this->error_code_ = SELF_TEST_FAILED;
+      ESP_LOGD(TAG, "Self-test failed 0x%X", reply);
+      return;
+    }
+
+    ESP_LOGD(TAG, "Self-test failed 0x%X", reply);
+    this->mark_failed();
+  });
+}
+
+/**
+ * @brief Combined the measured gasses, temperature, and humidity
+ * to calculate the VOC Index
+ *
+ * @param temperature The measured temperature in degrees C
+ * @param humidity The measured relative humidity in % rH
+ * @return int32_t The VOC Index
+ */
+bool SGP4xComponent::measure_gas_indices_(int32_t &voc, int32_t &nox) {
+  uint16_t voc_sraw;
+  uint16_t nox_sraw;
+  if (!measure_raw_(voc_sraw, nox_sraw))
+    return false;
+
+  this->status_clear_warning();
+
+  voc = voc_algorithm_.process(voc_sraw);
+  if (nox_sensor_) {
+    nox = nox_algorithm_.process(nox_sraw);
+  }
+  ESP_LOGV(TAG, "VOC = %d, NOx = %d", voc, nox);
+  // Store baselines after defined interval or if the difference between current and stored baseline becomes too
+  // much
+  if (this->store_baseline_ && this->seconds_since_last_store_ > SHORTEST_BASELINE_STORE_INTERVAL) {
+    voc_algorithm_.get_states(this->voc_state0_, this->voc_state1_);
+    if ((uint32_t) abs(this->voc_baselines_storage_.state0 - this->voc_state0_) > MAXIMUM_STORAGE_DIFF ||
+        (uint32_t) abs(this->voc_baselines_storage_.state1 - this->voc_state1_) > MAXIMUM_STORAGE_DIFF) {
+      this->seconds_since_last_store_ = 0;
+      this->voc_baselines_storage_.state0 = this->voc_state0_;
+      this->voc_baselines_storage_.state1 = this->voc_state1_;
+
+      if (this->pref_.save(&this->voc_baselines_storage_)) {
+        ESP_LOGI(TAG, "Stored VOC baseline state0: 0x%04X ,state1: 0x%04X", this->voc_baselines_storage_.state0,
+                 voc_baselines_storage_.state1);
+      } else {
+        ESP_LOGW(TAG, "Could not store VOC baselines");
+      }
+    }
+  }
+
+  return true;
+}
+/**
+ * @brief Return the raw gas measurement
+ *
+ * @param temperature The measured temperature in degrees C
+ * @param humidity The measured relative humidity in % rH
+ * @return uint16_t The current raw gas measurement
+ */
+bool SGP4xComponent::measure_raw_(uint16_t &voc_raw, uint16_t &nox_raw) {
+  float humidity = NAN;
+  static uint32_t nox_conditioning_start = millis();
+
+  if (!this->self_test_complete_) {
+    ESP_LOGD(TAG, "Self-test not yet complete");
+    return false;
+  }
+  if (this->humidity_sensor_ != nullptr) {
+    humidity = this->humidity_sensor_->state;
+  }
+  if (std::isnan(humidity) || humidity < 0.0f || humidity > 100.0f) {
+    humidity = 50;
+  }
+
+  float temperature = NAN;
+  if (this->temperature_sensor_ != nullptr) {
+    temperature = float(this->temperature_sensor_->state);
+  }
+  if (std::isnan(temperature) || temperature < -40.0f || temperature > 85.0f) {
+    temperature = 25;
+  }
+
+  uint16_t command;
+  uint16_t data[2];
+  size_t response_words;
+  // Use SGP40 measure command if we don't care about NOx
+  if (nox_sensor_ == nullptr) {
+    command = SGP40_CMD_MEASURE_RAW;
+    response_words = 1;
+  } else {
+    // SGP41 sensor must use NOx conditioning command for the first 10 seconds
+    if (millis() - nox_conditioning_start < 10000) {
+      command = SGP41_CMD_NOX_CONDITIONING;
+      response_words = 1;
+    } else {
+      command = SGP41_CMD_MEASURE_RAW;
+      response_words = 2;
+    }
+  }
+  uint16_t rhticks = llround((uint16_t)((humidity * 65535) / 100));
+  uint16_t tempticks = (uint16_t)(((temperature + 45) * 65535) / 175);
+  // first paramater are the relative humidity ticks
+  data[0] = rhticks;
+  // secomd paramater are the temperature ticks
+  data[1] = tempticks;
+
+  if (!this->write_command(command, data, 2)) {
+    this->status_set_warning();
+    ESP_LOGD(TAG, "write error (%d)", this->last_error_);
+    return false;
+  }
+  delay(measure_time_);
+  uint16_t raw_data[2];
+  raw_data[1] = 0;
+  if (!this->read_data(raw_data, response_words)) {
+    this->status_set_warning();
+    ESP_LOGD(TAG, "read error (%d)", this->last_error_);
+    return false;
+  }
+  voc_raw = raw_data[0];
+  nox_raw = raw_data[1];  // either 0 or the measured NOx ticks
+  return true;
+}
+
+void SGP4xComponent::update_gas_indices() {
+  if (!this->self_test_complete_)
+    return;
+
+  this->seconds_since_last_store_ += 1;
+  if (!this->measure_gas_indices_(this->voc_index_, this->nox_index_)) {
+    // Set values to UINT16_MAX to indicate failure
+    this->voc_index_ = this->nox_index_ = UINT16_MAX;
+    ESP_LOGE(TAG, "measure gas indices failed");
+    return;
+  }
+  if (this->samples_read_ < this->samples_to_stabilize_) {
+    this->samples_read_++;
+    ESP_LOGD(TAG, "Sensor has not collected enough samples yet. (%d/%d) VOC index is: %u", this->samples_read_,
+             this->samples_to_stabilize_, this->voc_index_);
+    return;
+  }
+}
+
+void SGP4xComponent::update() {
+  if (this->samples_read_ < this->samples_to_stabilize_) {
+    return;
+  }
+  if (this->voc_sensor_) {
+    if (this->voc_index_ != UINT16_MAX) {
+      this->status_clear_warning();
+      this->voc_sensor_->publish_state(this->voc_index_);
+    } else {
+      this->status_set_warning();
+    }
+  }
+  if (this->nox_sensor_) {
+    if (this->nox_index_ != UINT16_MAX) {
+      this->status_clear_warning();
+      this->nox_sensor_->publish_state(this->nox_index_);
+    } else {
+      this->status_set_warning();
+    }
+  }
+}
+
+void SGP4xComponent::dump_config() {
+  ESP_LOGCONFIG(TAG, "SGP4x:");
+  LOG_I2C_DEVICE(this);
+  ESP_LOGCONFIG(TAG, "  store_baseline: %d", this->store_baseline_);
+
+  if (this->is_failed()) {
+    switch (this->error_code_) {
+      case COMMUNICATION_FAILED:
+        ESP_LOGW(TAG, "Communication failed! Is the sensor connected?");
+        break;
+      case SERIAL_NUMBER_IDENTIFICATION_FAILED:
+        ESP_LOGW(TAG, "Get Serial number failed.");
+        break;
+      case SELF_TEST_FAILED:
+        ESP_LOGW(TAG, "Self test failed.");
+        break;
+
+      default:
+        ESP_LOGW(TAG, "Unknown setup error!");
+        break;
+    }
+  } else {
+    ESP_LOGCONFIG(TAG, "  Type: %s", sgp_type_ == SGP41 ? "SGP41" : "SPG40");
+    ESP_LOGCONFIG(TAG, "  Serial number: %" PRIu64, this->serial_number_);
+    ESP_LOGCONFIG(TAG, "  Minimum Samples: %f", GasIndexAlgorithm_INITIAL_BLACKOUT);
+  }
+  LOG_UPDATE_INTERVAL(this);
+
+  if (this->humidity_sensor_ != nullptr && this->temperature_sensor_ != nullptr) {
+    ESP_LOGCONFIG(TAG, "  Compensation:");
+    LOG_SENSOR("    ", "Temperature Source:", this->temperature_sensor_);
+    LOG_SENSOR("    ", "Humidity Source:", this->humidity_sensor_);
+  } else {
+    ESP_LOGCONFIG(TAG, "  Compensation: No source configured");
+  }
+  LOG_SENSOR("  ", "VOC", this->voc_sensor_);
+  LOG_SENSOR("  ", "NOx", this->nox_sensor_);
+}
+
+}  // namespace sgp4x
+}  // namespace esphome

esphome/components/sgp4x/sgp4x.h

@@ -0,0 +1,142 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/sensirion_common/i2c_sensirion.h"
+#include "esphome/core/application.h"
+#include "esphome/core/preferences.h"
+#include <VOCGasIndexAlgorithm.h>
+#include <NOxGasIndexAlgorithm.h>
+
+#include <cmath>
+
+namespace esphome {
+namespace sgp4x {
+
+struct SGP4xBaselines {
+  int32_t state0;
+  int32_t state1;
+} PACKED;  // NOLINT
+
+enum SgpType { SGP40, SGP41 };
+
+struct GasTuning {
+  uint16_t index_offset;
+  uint16_t learning_time_offset_hours;
+  uint16_t learning_time_gain_hours;
+  uint16_t gating_max_duration_minutes;
+  uint16_t std_initial;
+  uint16_t gain_factor;
+};
+
+// commands and constants
+static const uint8_t SGP40_FEATURESET = 0x0020;  // can measure VOC
+static const uint8_t SGP41_FEATURESET = 0x0040;  // can measure VOC and NOX
+// Commands
+static const uint16_t SGP4X_CMD_GET_SERIAL_ID = 0x3682;
+static const uint16_t SGP4X_CMD_GET_FEATURESET = 0x202f;
+static const uint16_t SGP4X_CMD_SELF_TEST = 0x280e;
+static const uint16_t SGP40_CMD_MEASURE_RAW = 0x260F;
+static const uint16_t SGP41_CMD_MEASURE_RAW = 0x2619;
+static const uint16_t SGP41_CMD_NOX_CONDITIONING = 0x2612;
+static const uint8_t SGP41_SUBCMD_NOX_CONDITIONING = 0x12;
+
+// 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;
+static const uint16_t SPG40_SELFTEST_TIME = 250;  // 250 ms for self test
+static const uint16_t SPG41_SELFTEST_TIME = 320;  // 320 ms for self test
+static const uint16_t SGP40_MEASURE_TIME = 30;
+static const uint16_t SGP41_MEASURE_TIME = 55;
+// Store anyway if the baseline difference exceeds the max storage diff value
+const uint32_t MAXIMUM_STORAGE_DIFF = 50;
+
+class SGP4xComponent;
+
+/// This class implements support for the Sensirion sgp4x i2c GAS (VOC) sensors.
+class SGP4xComponent : public PollingComponent, public sensor::Sensor, public sensirion_common::SensirionI2CDevice {
+  enum ErrorCode {
+    COMMUNICATION_FAILED,
+    MEASUREMENT_INIT_FAILED,
+    INVALID_ID,
+    UNSUPPORTED_ID,
+    SERIAL_NUMBER_IDENTIFICATION_FAILED,
+    SELF_TEST_FAILED,
+    UNKNOWN
+  } error_code_{UNKNOWN};
+
+ public:
+  // SGP4xComponent()  {};
+  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_gas_indices();
+  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; }
+  void set_voc_sensor(sensor::Sensor *voc_sensor) { voc_sensor_ = voc_sensor; }
+  void set_nox_sensor(sensor::Sensor *nox_sensor) { nox_sensor_ = nox_sensor; }
+  void set_voc_algorithm_tuning(uint16_t index_offset, uint16_t learning_time_offset_hours,
+                                uint16_t learning_time_gain_hours, uint16_t gating_max_duration_minutes,
+                                uint16_t std_initial, uint16_t gain_factor) {
+    voc_tuning_params_.value().index_offset = index_offset;
+    voc_tuning_params_.value().learning_time_offset_hours = learning_time_offset_hours;
+    voc_tuning_params_.value().learning_time_gain_hours = learning_time_gain_hours;
+    voc_tuning_params_.value().gating_max_duration_minutes = gating_max_duration_minutes;
+    voc_tuning_params_.value().std_initial = std_initial;
+    voc_tuning_params_.value().gain_factor = gain_factor;
+  }
+  void set_nox_algorithm_tuning(uint16_t index_offset, uint16_t learning_time_offset_hours,
+                                uint16_t learning_time_gain_hours, uint16_t gating_max_duration_minutes,
+                                uint16_t gain_factor) {
+    nox_tuning_params_.value().index_offset = index_offset;
+    nox_tuning_params_.value().learning_time_offset_hours = learning_time_offset_hours;
+    nox_tuning_params_.value().learning_time_gain_hours = learning_time_gain_hours;
+    nox_tuning_params_.value().gating_max_duration_minutes = gating_max_duration_minutes;
+    nox_tuning_params_.value().std_initial = 50;
+    nox_tuning_params_.value().gain_factor = gain_factor;
+  }
+
+ protected:
+  void self_test_();
+
+  /// Input sensor for humidity and temperature compensation.
+  sensor::Sensor *humidity_sensor_{nullptr};
+  sensor::Sensor *temperature_sensor_{nullptr};
+  int16_t sensirion_init_sensors_();
+
+  bool measure_gas_indices_(int32_t &voc, int32_t &nox);
+  bool measure_raw_(uint16_t &voc_raw, uint16_t &nox_raw);
+
+  SgpType sgp_type_{SGP40};
+  uint64_t serial_number_;
+  uint16_t featureset_;
+
+  bool self_test_complete_;
+  uint16_t self_test_time_;
+
+  sensor::Sensor *voc_sensor_{nullptr};
+  VOCGasIndexAlgorithm voc_algorithm_;
+  optional<GasTuning> voc_tuning_params_;
+  int32_t voc_state0_;
+  int32_t voc_state1_;
+  int32_t voc_index_ = 0;
+
+  sensor::Sensor *nox_sensor_{nullptr};
+  int32_t nox_index_ = 0;
+  NOxGasIndexAlgorithm nox_algorithm_;
+  optional<GasTuning> nox_tuning_params_;
+
+  uint16_t measure_time_;
+  uint8_t samples_read_ = 0;
+  uint8_t samples_to_stabilize_ = static_cast<int8_t>(GasIndexAlgorithm_INITIAL_BLACKOUT) * 2;
+
+  bool store_baseline_;
+  ESPPreferenceObject pref_;
+  uint32_t seconds_since_last_store_;
+  SGP4xBaselines voc_baselines_storage_;
+};
+}  // namespace sgp4x
+}  // namespace esphome