BH1750 Measurement time (#997)

* BH1750 Measurement time

Fixes esphome/feature-requests#148

* lint

* add test

Co-authored-by: Otto Winter <otto@otto-winter.com>
Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

esphome/components/bh1750/bh1750.cpp

@@ -7,14 +7,22 @@ namespace bh1750 {
 static const char *TAG = "bh1750.sensor";
 
 static const uint8_t BH1750_COMMAND_POWER_ON = 0b00000001;
+static const uint8_t BH1750_COMMAND_MT_REG_HI = 0b01000000;  // last 3 bits
+static const uint8_t BH1750_COMMAND_MT_REG_LO = 0b01100000;  // last 5 bits
 
 void BH1750Sensor::setup() {
   ESP_LOGCONFIG(TAG, "Setting up BH1750 '%s'...", this->name_.c_str());
   if (!this->write_bytes(BH1750_COMMAND_POWER_ON, nullptr, 0)) {
     this->mark_failed();
     return;
   }
+
+  uint8_t mtreg_hi = (this->measurement_time_ >> 5) & 0b111;
+  uint8_t mtreg_lo = (this->measurement_time_ >> 0) & 0b11111;
+  this->write_bytes(BH1750_COMMAND_MT_REG_HI | mtreg_hi, nullptr, 0);
+  this->write_bytes(BH1750_COMMAND_MT_REG_LO | mtreg_lo, nullptr, 0);
 }
+
 void BH1750Sensor::dump_config() {
   LOG_SENSOR("", "BH1750", this);
   LOG_I2C_DEVICE(this);
@@ -59,6 +67,7 @@ void BH1750Sensor::update() {
 
   this->set_timeout("illuminance", wait, [this]() { this->read_data_(); });
 }
+
 float BH1750Sensor::get_setup_priority() const { return setup_priority::DATA; }
 void BH1750Sensor::read_data_() {
   uint16_t raw_value;
@@ -68,10 +77,12 @@ void BH1750Sensor::read_data_() {
   }
 
   float lx = float(raw_value) / 1.2f;
+  lx *= 69.0f / this->measurement_time_;
   ESP_LOGD(TAG, "'%s': Got illuminance=%.1flx", this->get_name().c_str(), lx);
   this->publish_state(lx);
   this->status_clear_warning();
 }
+
 void BH1750Sensor::set_resolution(BH1750Resolution resolution) { this->resolution_ = resolution; }
 
 }  // namespace bh1750

esphome/components/bh1750/bh1750.h

@@ -28,6 +28,7 @@ class BH1750Sensor : public sensor::Sensor, public PollingComponent, public i2c:
    * @param resolution The new resolution of the sensor.
    */
   void set_resolution(BH1750Resolution resolution);
+  void set_measurement_time(uint8_t measurement_time) { measurement_time_ = measurement_time; }
 
   // ========== INTERNAL METHODS ==========
   // (In most use cases you won't need these)
@@ -40,6 +41,7 @@ class BH1750Sensor : public sensor::Sensor, public PollingComponent, public i2c:
   void read_data_();
 
   BH1750Resolution resolution_{BH1750_RESOLUTION_0P5_LX};
+  uint8_t measurement_time_;
 };
 
 }  // namespace bh1750

esphome/components/bh1750/sensor.py

@@ -15,9 +15,11 @@
 
 BH1750Sensor = bh1750_ns.class_('BH1750Sensor', sensor.Sensor, cg.PollingComponent, i2c.I2CDevice)
 
+CONF_MEASUREMENT_TIME = 'measurement_time'
 CONFIG_SCHEMA = sensor.sensor_schema(UNIT_LUX, ICON_BRIGHTNESS_5, 1).extend({
     cv.GenerateID(): cv.declare_id(BH1750Sensor),
     cv.Optional(CONF_RESOLUTION, default=0.5): cv.enum(BH1750_RESOLUTIONS, float=True),
+    cv.Optional(CONF_MEASUREMENT_TIME, default=69): cv.int_range(min=31, max=254),
 }).extend(cv.polling_component_schema('60s')).extend(i2c.i2c_device_schema(0x23))
 
 
@@ -28,3 +30,4 @@ def to_code(config):
     yield i2c.register_i2c_device(var, config)
 
     cg.add(var.set_resolution(config[CONF_RESOLUTION]))
+    cg.add(var.set_measurement_time(config[CONF_MEASUREMENT_TIME]))

tests/test1.yaml

@@ -308,6 +308,7 @@ sensor:
     retain: False
     availability:
     state_topic: livingroom/custom_state_topic
+    measurement_time: 31
   - platform: bme280
     temperature:
       name: "Outside Temperature"
@@ -1169,7 +1170,6 @@ light:
             if (initial_run) {
               it[0] = current_color;
             }
-
     - automation:
         name: Custom Effect
         sequence: