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))