Add MCP9808 temperature sensor (#1169)

* Add MCP9808 temperature sensor

* Change from component to sensor; code fixes

- Change from component to sensor
- Change magic numbers to constants

* Fix incorrect logging levels

* Add precision to debug log

* Fix logging level

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

* Fix bug with comparison to NAN

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

esphome/components/mcp9808/mcp9808.cpp

@@ -0,0 +1,81 @@
+#include "mcp9808.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace mcp9808 {
+
+static const uint8_t MCP9808_REG_AMBIENT_TEMP = 0x05;
+static const uint8_t MCP9808_REG_MANUF_ID = 0x06;
+static const uint8_t MCP9808_REG_DEVICE_ID = 0x07;
+
+static const uint16_t MCP9808_MANUF_ID = 0x0054;
+static const uint16_t MCP9808_DEV_ID = 0x0400;
+
+static const uint8_t MCP9808_AMBIENT_CLEAR_FLAGS = 0x1F;
+static const uint8_t MCP9808_AMBIENT_CLEAR_SIGN = 0x0F;
+static const uint8_t MCP9808_AMBIENT_TEMP_NEGATIVE = 0x10;
+
+static const char *TAG = "mcp9808";
+
+void MCP9808Sensor::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up %s...", this->name_.c_str());
+
+  uint16_t manu;
+  if (!this->read_byte_16(MCP9808_REG_MANUF_ID, &manu, 0) || manu != MCP9808_MANUF_ID) {
+    this->mark_failed();
+    ESP_LOGE(TAG, "%s manufacuturer id failed, device returned %X", this->name_.c_str(), manu);
+    return;
+  }
+  uint16_t dev_id;
+  if (!this->read_byte_16(MCP9808_REG_DEVICE_ID, &dev_id, 0) || dev_id != MCP9808_DEV_ID) {
+    this->mark_failed();
+    ESP_LOGE(TAG, "%s device id failed, device returned %X", this->name_.c_str(), dev_id);
+    return;
+  }
+}
+void MCP9808Sensor::dump_config() {
+  ESP_LOGCONFIG(TAG, "%s:", this->name_.c_str());
+  LOG_I2C_DEVICE(this);
+  if (this->is_failed()) {
+    ESP_LOGE(TAG, "Communication with %s failed!", this->name_.c_str());
+  }
+  LOG_UPDATE_INTERVAL(this);
+  LOG_SENSOR("  ", "Temperature", this);
+}
+void MCP9808Sensor::update() {
+  uint16_t raw_temp;
+  if (!this->read_byte_16(MCP9808_REG_AMBIENT_TEMP, &raw_temp)) {
+    this->status_set_warning();
+    return;
+  }
+  if (raw_temp == 0xFFFF) {
+    this->status_set_warning();
+    return;
+  }
+
+  float temp = NAN;
+  uint8_t msb = (uint8_t)((raw_temp & 0xff00) >> 8);
+  uint8_t lsb = raw_temp & 0x00ff;
+
+  msb = msb & MCP9808_AMBIENT_CLEAR_FLAGS;
+
+  if ((msb & MCP9808_AMBIENT_TEMP_NEGATIVE) == MCP9808_AMBIENT_TEMP_NEGATIVE) {
+    msb = msb & MCP9808_AMBIENT_CLEAR_SIGN;
+    temp = (256 - ((uint16_t)(msb) *16 + lsb / 16.0f)) * -1;
+  } else {
+    temp = (uint16_t)(msb) *16 + lsb / 16.0f;
+  }
+
+  if (isnan(temp)) {
+    this->status_set_warning();
+    return;
+  }
+
+  ESP_LOGD(TAG, "%s: Got temperature=%.4f°C", this->name_.c_str(), temp);
+  this->publish_state(temp);
+  this->status_clear_warning();
+}
+float MCP9808Sensor::get_setup_priority() const { return setup_priority::DATA; }
+
+}  // namespace mcp9808
+}  // namespace esphome

esphome/components/mcp9808/mcp9808.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/i2c/i2c.h"
+
+namespace esphome {
+namespace mcp9808 {
+
+class MCP9808Sensor : public sensor::Sensor, public PollingComponent, public i2c::I2CDevice {
+ public:
+  void setup() override;
+  void dump_config() override;
+  float get_setup_priority() const override;
+
+  void update() override;
+};
+
+}  // namespace mcp9808
+}  // namespace esphome

esphome/components/mcp9808/sensor.py

@@ -0,0 +1,21 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import i2c, sensor
+from esphome.const import CONF_ID, ICON_THERMOMETER, UNIT_CELSIUS
+
+DEPENDENCIES = ['i2c']
+
+mcp9808_ns = cg.esphome_ns.namespace('mcp9808')
+MCP9808Sensor = mcp9808_ns.class_('MCP9808Sensor', sensor.Sensor, cg.PollingComponent,
+                                  i2c.I2CDevice)
+
+CONFIG_SCHEMA = sensor.sensor_schema(UNIT_CELSIUS, ICON_THERMOMETER, 1).extend({
+    cv.GenerateID(): cv.declare_id(MCP9808Sensor),
+}).extend(cv.polling_component_schema('60s')).extend(i2c.i2c_device_schema(0x18))
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield i2c.register_i2c_device(var, config)
+    yield sensor.register_sensor(var, config)

tests/test1.yaml

@@ -757,6 +757,9 @@ sensor:
     aqi:
       name: "AQI"
       calculation_type: "CAQI"
+  - platform: mcp9808
+    name: "MCP9808 Temperature"
+    update_interval: 15s
 
 esp32_touch:
   setup_mode: False