Add support for SHTCx Temperature sensors (#676)

* Add support for Sensirion STS3x Temperature sensors

* Removed humidty reading from STS3x sensor

* Fixed line error and operand error

* Fixed syntax

* Add test snippet for STS3x sensor

* Clean up

* Add support for Sensirion SHTC1 and SHTC3 Temperature sensors

* Fixed the test

* Fix lint issues

* Update esphome/components/shtcx/shtcx.cpp

Good point.

Co-Authored-By: Otto Winter <otto@otto-winter.com>

* Refactored device type identification and logging

* Refactoring and cleanup

* Remove sts3x


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

esphome/components/shtcx/sensor.py

@@ -0,0 +1,32 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import i2c, sensor
+from esphome.const import CONF_HUMIDITY, CONF_ID, CONF_TEMPERATURE, ICON_WATER_PERCENT, \
+    ICON_THERMOMETER, UNIT_CELSIUS, UNIT_PERCENT
+
+DEPENDENCIES = ['i2c']
+
+shtcx_ns = cg.esphome_ns.namespace('shtcx')
+SHTCXComponent = shtcx_ns.class_('SHTCXComponent', cg.PollingComponent, i2c.I2CDevice)
+
+SHTCXType = shtcx_ns.enum('SHTCXType')
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_id(SHTCXComponent),
+    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(0x70))
+
+
+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_TEMPERATURE in config:
+        sens = yield sensor.new_sensor(config[CONF_TEMPERATURE])
+        cg.add(var.set_temperature_sensor(sens))
+
+    if CONF_HUMIDITY in config:
+        sens = yield sensor.new_sensor(config[CONF_HUMIDITY])
+        cg.add(var.set_humidity_sensor(sens))

esphome/components/shtcx/shtcx.cpp

@@ -0,0 +1,166 @@
+#include "shtcx.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace shtcx {
+
+static const char *TAG = "shtcx";
+
+static const uint16_t SHTCX_COMMAND_SLEEP = 0xB098;
+static const uint16_t SHTCX_COMMAND_WAKEUP = 0x3517;
+static const uint16_t SHTCX_COMMAND_READ_ID_REGISTER = 0xEFC8;
+static const uint16_t SHTCX_COMMAND_SOFT_RESET = 0x805D;
+static const uint16_t SHTCX_COMMAND_POLLING_H = 0x7866;
+
+inline const char* to_string(SHTCXType type) {
+  switch (type) {
+    case SHTCX_TYPE_SHTC3:
+      return "SHTC3";
+    case SHTCX_TYPE_SHTC1:
+      return "SHTC1";
+    default:
+      return "[Unknown model]";
+  }
+}
+
+void SHTCXComponent::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up SHTCx...");
+  this->soft_reset();
+
+  if (!this->write_command_(SHTCX_COMMAND_READ_ID_REGISTER)) {
+    ESP_LOGE(TAG, "Error requesting Device ID");
+    this->mark_failed();
+    return;
+  }
+
+  uint16_t device_id_register[1];
+  if (!this->read_data_(device_id_register, 1)) {
+    ESP_LOGE(TAG, "Error reading Device ID");
+    this->mark_failed();
+    return;
+  }
+
+  if (((device_id_register[0] << 2) & 0x1C) == 0x1C) {
+    if ((device_id_register[0] & 0x847) == 0x847) {
+      this->type_ = SHTCX_TYPE_SHTC3;
+    } else {
+      this->type_ = SHTCX_TYPE_SHTC1;
+    }
+  } else {
+    this->type_ = SHTCX_TYPE_UNKNOWN;
+  }
+  ESP_LOGCONFIG(TAG, "  Device identified: %s", to_string(this->type_));
+}
+void SHTCXComponent::dump_config() {
+  ESP_LOGCONFIG(TAG, "SHTCx:");
+  ESP_LOGCONFIG(TAG, "  Model: %s", to_string(this->type_));
+  LOG_I2C_DEVICE(this);
+  if (this->is_failed()) {
+    ESP_LOGE(TAG, "Communication with SHTCx failed!");
+  }
+  LOG_UPDATE_INTERVAL(this);
+
+  LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
+  LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
+}
+float SHTCXComponent::get_setup_priority() const { return setup_priority::DATA; }
+void SHTCXComponent::update() {
+  if (this->status_has_warning()) {
+    ESP_LOGW(TAG, "Retrying to reconnect the sensor.");
+    this->soft_reset();
+  }
+  if (this->type_ != SHTCX_TYPE_SHTC1) {
+    this->wake_up();
+  }
+  if (!this->write_command_(SHTCX_COMMAND_POLLING_H)) {
+    this->status_set_warning();
+    return;
+  }
+
+  this->set_timeout(50, [this]() {
+    uint16_t raw_data[2];
+    if (!this->read_data_(raw_data, 2)) {
+      this->status_set_warning();
+      return;
+    }
+
+    float temperature = 175.0f * float(raw_data[0]) / 65536.0f - 45.0f;
+    float humidity = 100.0f * float(raw_data[1]) / 65536.0f;
+
+    ESP_LOGD(TAG, "Got temperature=%.2f°C humidity=%.2f%%", temperature, humidity);
+    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();
+    if (this->type_ != SHTCX_TYPE_SHTC1) {
+      this->sleep();
+    }
+  });
+}
+
+bool SHTCXComponent::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 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 SHTCXComponent::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;
+}
+
+void SHTCXComponent::soft_reset() {
+  this->write_command_(SHTCX_COMMAND_SOFT_RESET);
+  delayMicroseconds(200);
+}
+void SHTCXComponent::sleep() { this->write_command_(SHTCX_COMMAND_SLEEP); }
+
+void SHTCXComponent::wake_up() {
+  this->write_command_(SHTCX_COMMAND_WAKEUP);
+  delayMicroseconds(200);
+}
+
+}  // namespace shtcx
+}  // namespace esphome

esphome/components/shtcx/shtcx.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/i2c/i2c.h"
+
+namespace esphome {
+namespace shtcx {
+
+enum SHTCXType { SHTCX_TYPE_SHTC3 = 0, SHTCX_TYPE_SHTC1, SHTCX_TYPE_UNKNOWN };
+
+/// This class implements support for the SHT3x-DIS family of temperature+humidity i2c sensors.
+class SHTCXComponent : public PollingComponent, public i2c::I2CDevice {
+ public:
+  void set_temperature_sensor(sensor::Sensor *temperature_sensor) { temperature_sensor_ = temperature_sensor; }
+  void set_humidity_sensor(sensor::Sensor *humidity_sensor) { humidity_sensor_ = humidity_sensor; }
+
+  void setup() override;
+  void dump_config() override;
+  float get_setup_priority() const override;
+  void update() override;
+  void soft_reset();
+  void sleep();
+  void wake_up();
+
+ protected:
+  bool write_command_(uint16_t command);
+  bool read_data_(uint16_t *data, uint8_t len);
+  SHTCXType type_;
+  sensor::Sensor *temperature_sensor_;
+  sensor::Sensor *humidity_sensor_;
+};
+
+}  // namespace shtcx
+}  // namespace esphome

tests/test1.yaml

@@ -540,6 +540,13 @@ sensor:
       accuracy_decimals: 1
     address: 0x58
     update_interval: 5s
+  - platform: shtcx
+      temperature:
+        name: "Living Room Temperature 10"
+      humidity:
+        name: "Living Room Humidity 10"
+      address: 0x70
+      update_interval: 15s
   - platform: template
     name: "Template Sensor"
     id: template_sensor