Add support for Sensirion SCD30 CO2 sensors (#712)

* Add support for Sensirion SCD30 CO2 sensors

* Fixed few lint issues

* Lint fixes

* Fixed line ending for lint

* Cleanup

* Refactored float conversion

* Refactor unnecessary return


Co-authored-by: Otto Winter <otto@otto-winter.com>

esphome/components/scd30/scd30.cpp

@@ -0,0 +1,176 @@
+#include "scd30.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace scd30 {
+
+static const char *TAG = "scd30";
+
+static const uint16_t SCD30_CMD_GET_FIRMWARE_VERSION = 0xd100;
+static const uint16_t SCD30_CMD_START_CONTINUOUS_MEASUREMENTS = 0x0010;
+static const uint16_t SCD30_CMD_GET_DATA_READY_STATUS = 0x0202;
+static const uint16_t SCD30_CMD_READ_MEASUREMENT = 0x0300;
+
+/// Commands for future use
+static const uint16_t SCD30_CMD_STOP_MEASUREMENTS = 0x0104;
+static const uint16_t SCD30_CMD_MEASUREMENT_INTERVAL = 0x4600;
+static const uint16_t SCD30_CMD_AUTOMATIC_SELF_CALIBRATION = 0x5306;
+static const uint16_t SCD30_CMD_FORCED_CALIBRATION = 0x5204;
+static const uint16_t SCD30_CMD_TEMPERATURE_OFFSET = 0x5403;
+static const uint16_t SCD30_CMD_ALTITUDE_COMPENSATION = 0x5102;
+static const uint16_t SCD30_CMD_SOFT_RESET = 0xD304;
+
+void SCD30Component::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up scd30...");
+
+  /// Firmware version identification
+  if (!this->write_command_(SCD30_CMD_GET_FIRMWARE_VERSION)) {
+    this->error_code_ = COMMUNICATION_FAILED;
+    this->mark_failed();
+    return;
+  }
+  uint16_t raw_firmware_version[3];
+
+  if (!this->read_data_(raw_firmware_version, 3)) {
+    this->error_code_ = FIRMWARE_IDENTIFICATION_FAILED;
+    this->mark_failed();
+    return;
+  }
+  ESP_LOGD(TAG, "SCD30 Firmware v%0d.%02d", (uint16_t(raw_firmware_version[0]) >> 8),
+           uint16_t(raw_firmware_version[0] & 0xFF));
+
+  /// Sensor initialization
+  if (!this->write_command_(SCD30_CMD_START_CONTINUOUS_MEASUREMENTS)) {
+    ESP_LOGE(TAG, "Sensor SCD30 error starting continuous measurements.");
+    this->error_code_ = MEASUREMENT_INIT_FAILED;
+    this->mark_failed();
+    return;
+  }
+}
+
+void SCD30Component::dump_config() {
+  ESP_LOGCONFIG(TAG, "scd30:");
+  LOG_I2C_DEVICE(this);
+  if (this->is_failed()) {
+    switch (this->error_code_) {
+      case COMMUNICATION_FAILED:
+        ESP_LOGW(TAG, "Communication failed! Is the sensor connected?");
+        break;
+      case MEASUREMENT_INIT_FAILED:
+        ESP_LOGW(TAG, "Measurement Initialization failed!");
+        break;
+      case FIRMWARE_IDENTIFICATION_FAILED:
+        ESP_LOGW(TAG, "Unable to read sensor firmware version");
+        break;
+      default:
+        ESP_LOGW(TAG, "Unknown setup error!");
+        break;
+    }
+  }
+  LOG_UPDATE_INTERVAL(this);
+  LOG_SENSOR("  ", "CO2", this->co2_sensor_);
+  LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
+  LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
+}
+
+void SCD30Component::update() {
+  /// Check if measurement is ready before reading the value
+  if (!this->write_command_(SCD30_CMD_GET_DATA_READY_STATUS)) {
+    this->status_set_warning();
+    return;
+  }
+
+  uint16_t raw_read_status[1];
+  if (!this->read_data_(raw_read_status, 1) || raw_read_status[0] == 0x00) {
+    this->status_set_warning();
+    ESP_LOGW(TAG, "Data not ready yet!");
+    return;
+  }
+
+  if (!this->write_command_(SCD30_CMD_READ_MEASUREMENT)) {
+    ESP_LOGW(TAG, "Error reading measurement!");
+    this->status_set_warning();
+    return;
+  }
+
+  this->set_timeout(50, [this]() {
+    uint16_t raw_data[6];
+    if (!this->read_data_(raw_data, 6)) {
+      this->status_set_warning();
+      return;
+    }
+    uint32_t temp_c_o2_u32 = (((uint32_t(raw_data[0])) << 16) | (uint32_t(raw_data[1])));
+    float co2 = *reinterpret_cast<float *>(&temp_c_o2_u32);
+
+    uint32_t temp_temp_u32 = (((uint32_t(raw_data[2])) << 16) | (uint32_t(raw_data[3])));
+    float temperature = *reinterpret_cast<float *>(&temp_temp_u32);
+
+    uint32_t temp_hum_u32 = (((uint32_t(raw_data[4])) << 16) | (uint32_t(raw_data[5])));
+    float humidity = *reinterpret_cast<float *>(&temp_hum_u32);
+
+    ESP_LOGD(TAG, "Got CO2=%.2fppm temperature=%.2f°C humidity=%.2f%%", co2, temperature, humidity);
+    if (this->co2_sensor_ != nullptr)
+      this->co2_sensor_->publish_state(co2);
+    if (this->temperature_sensor_ != nullptr)
+      this->temperature_sensor_->publish_state(temperature);
+    if (this->humidity_sensor_ != nullptr)
+      this->humidity_sensor_->publish_state(humidity);
+
+    this->status_clear_warning();
+  });
+}
+
+bool SCD30Component::write_command_(uint16_t command) {
+  // Warning ugly, trick the I2Ccomponent base by setting register to the first 8 bit.
+  return this->write_byte(command >> 8, command & 0xFF);
+}
+
+uint8_t SCD30Component::sht_crc_(uint8_t data1, uint8_t data2) {
+  uint8_t bit;
+  uint8_t crc = 0xFF;
+
+  crc ^= data1;
+  for (bit = 8; bit > 0; --bit) {
+    if (crc & 0x80)
+      crc = (crc << 1) ^ 0x131;
+    else
+      crc = (crc << 1);
+  }
+
+  crc ^= data2;
+  for (bit = 8; bit > 0; --bit) {
+    if (crc & 0x80)
+      crc = (crc << 1) ^ 0x131;
+    else
+      crc = (crc << 1);
+  }
+
+  return crc;
+}
+
+bool SCD30Component::read_data_(uint16_t *data, uint8_t len) {
+  const uint8_t num_bytes = len * 3;
+  auto *buf = new uint8_t[num_bytes];
+
+  if (!this->parent_->raw_receive(this->address_, buf, num_bytes)) {
+    delete[](buf);
+    return false;
+  }
+
+  for (uint8_t i = 0; i < len; i++) {
+    const uint8_t j = 3 * i;
+    uint8_t crc = sht_crc_(buf[j], buf[j + 1]);
+    if (crc != buf[j + 2]) {
+      ESP_LOGE(TAG, "CRC8 Checksum invalid! 0x%02X != 0x%02X", buf[j + 2], crc);
+      delete[](buf);
+      return false;
+    }
+    data[i] = (buf[j] << 8) | buf[j + 1];
+  }
+
+  delete[](buf);
+  return true;
+}
+
+}  // namespace scd30
+}  // namespace esphome

esphome/components/scd30/scd30.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/i2c/i2c.h"
+
+namespace esphome {
+namespace scd30 {
+
+/// This class implements support for the Sensirion scd30 i2c GAS (VOC and CO2eq) sensors.
+class SCD30Component : public PollingComponent, public i2c::I2CDevice {
+ public:
+  void set_co2_sensor(sensor::Sensor *co2) { co2_sensor_ = co2; }
+  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 dump_config() override;
+  float get_setup_priority() const override { return setup_priority::DATA; }
+
+ protected:
+  bool write_command_(uint16_t command);
+  bool read_data_(uint16_t *data, uint8_t len);
+  uint8_t sht_crc_(uint8_t data1, uint8_t data2);
+
+  enum ErrorCode {
+    COMMUNICATION_FAILED,
+    FIRMWARE_IDENTIFICATION_FAILED,
+    MEASUREMENT_INIT_FAILED,
+    UNKNOWN
+  } error_code_{UNKNOWN};
+
+  sensor::Sensor *co2_sensor_{nullptr};
+  sensor::Sensor *humidity_sensor_{nullptr};
+  sensor::Sensor *temperature_sensor_{nullptr};
+};
+
+}  // namespace scd30
+}  // namespace esphome

esphome/components/scd30/sensor.py

@@ -0,0 +1,39 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import i2c, sensor
+from esphome.const import CONF_ID, UNIT_PARTS_PER_MILLION, \
+    CONF_HUMIDITY, CONF_TEMPERATURE, ICON_PERIODIC_TABLE_CO2, \
+    UNIT_CELSIUS, ICON_THERMOMETER, ICON_WATER_PERCENT, UNIT_PERCENT
+
+DEPENDENCIES = ['i2c']
+
+scd30_ns = cg.esphome_ns.namespace('scd30')
+SCD30Component = scd30_ns.class_('SCD30Component', cg.PollingComponent, i2c.I2CDevice)
+
+CONF_CO2 = 'co2'
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_id(SCD30Component),
+    cv.Required(CONF_CO2): sensor.sensor_schema(UNIT_PARTS_PER_MILLION,
+                                                ICON_PERIODIC_TABLE_CO2, 0),
+    cv.Required(CONF_TEMPERATURE): sensor.sensor_schema(UNIT_CELSIUS, ICON_THERMOMETER, 1),
+    cv.Required(CONF_HUMIDITY): sensor.sensor_schema(UNIT_PERCENT, ICON_WATER_PERCENT, 1),
+}).extend(cv.polling_component_schema('60s')).extend(i2c.i2c_device_schema(0x61))
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield i2c.register_i2c_device(var, config)
+
+    if CONF_CO2 in config:
+        sens = yield sensor.new_sensor(config[CONF_CO2])
+        cg.add(var.set_co2_sensor(sens))
+
+    if CONF_HUMIDITY in config:
+        sens = yield sensor.new_sensor(config[CONF_HUMIDITY])
+        cg.add(var.set_humidity_sensor(sens))
+
+    if CONF_TEMPERATURE in config:
+        sens = yield sensor.new_sensor(config[CONF_TEMPERATURE])
+        cg.add(var.set_temperature_sensor(sens))

tests/test1.yaml

@@ -507,6 +507,15 @@ sensor:
       name: "Living Room Humidity 8"
     address: 0x44
     update_interval: 15s
+  - platform: scd30
+    co2:
+      name: "Living Room CO2 9"
+    temperature:
+      name: "Living Room Temperature 9"
+    humidity:
+      name: "Living Room Humidity 9"
+    address: 0x61
+    update_interval: 15s
   - platform: template
     name: "Template Sensor"
     id: template_sensor