dht12.cpp

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// Implementation based on:
//  - ESPEasy: https://github.com/letscontrolit/ESPEasy/blob/mega/src/_P034_DHT12.ino
//  - DHT12_sensor_library: https://github.com/xreef/DHT12_sensor_library/blob/master/DHT12.cpp
 
#include "dht12.h"
#include "esphome/core/log.h"
 
namespace esphome::dht12 {
 
static const char *const TAG = "dht12";
 
void DHT12Component::update() {
  uint8_t data[5];
  if (!this->read_data_(data)) {
    this->status_set_warning();
    return;
  }
  const uint16_t raw_temperature = uint16_t(data[2]) * 10 + (data[3] & 0x7F);
  float temperature = raw_temperature / 10.0f;
  if ((data[3] & 0x80) != 0) {
    // negative
    temperature *= -1;
  }
 
  const uint16_t raw_humidity = uint16_t(data[0]) * 10 + data[1];
  float humidity = raw_humidity / 10.0f;
 
  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();
}
void DHT12Component::setup() {
  uint8_t data[5];
  if (!this->read_data_(data)) {
    this->mark_failed();
    return;
  }
}
void DHT12Component::dump_config() {
  ESP_LOGD(TAG, "DHT12:");
  LOG_I2C_DEVICE(this);
  if (this->is_failed()) {
    ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
  }
  LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
  LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
}
 
bool DHT12Component::read_data_(uint8_t *data) {
  if (!this->read_bytes(0, data, 5)) {
    ESP_LOGW(TAG, "Updating DHT12 failed!");
    return false;
  }
 
  uint8_t checksum = data[0] + data[1] + data[2] + data[3];
  if (data[4] != checksum) {
    ESP_LOGW(TAG, "DHT12 Checksum invalid!");
    return false;
  }
 
  return true;
}
 
}  // namespace esphome::dht12