pm1006: add rx-only support (#2038)

esphome/components/pm1006/pm1006.cpp

@@ -0,0 +1,96 @@
+#include "pm1006.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace pm1006 {
+
+static const char *const TAG = "pm1006";
+
+static const uint8_t PM1006_RESPONSE_HEADER[] = {0x16, 0x11, 0x0B};
+
+void PM1006Component::setup() {
+  // because this implementation is currently rx-only, there is nothing to setup
+}
+
+void PM1006Component::dump_config() {
+  ESP_LOGCONFIG(TAG, "PM1006:");
+  LOG_SENSOR("  ", "PM2.5", this->pm_2_5_sensor_);
+  this->check_uart_settings(9600);
+}
+
+void PM1006Component::loop() {
+  while (this->available() != 0) {
+    this->read_byte(&this->data_[this->data_index_]);
+    auto check = this->check_byte_();
+    if (!check.has_value()) {
+      // finished
+      this->parse_data_();
+      this->data_index_ = 0;
+    } else if (!*check) {
+      // wrong data
+      ESP_LOGV(TAG, "Byte %i of received data frame is invalid.", this->data_index_);
+      this->data_index_ = 0;
+    } else {
+      // next byte
+      this->data_index_++;
+    }
+  }
+}
+
+float PM1006Component::get_setup_priority() const { return setup_priority::DATA; }
+
+uint8_t PM1006Component::pm1006_checksum_(const uint8_t *command_data, uint8_t length) const {
+  uint8_t sum = 0;
+  for (uint8_t i = 0; i < length; i++) {
+    sum += command_data[i];
+  }
+  return sum;
+}
+
+optional<bool> PM1006Component::check_byte_() const {
+  uint8_t index = this->data_index_;
+  uint8_t byte = this->data_[index];
+
+  // index 0..2 are the fixed header
+  if (index < sizeof(PM1006_RESPONSE_HEADER)) {
+    return byte == PM1006_RESPONSE_HEADER[index];
+  }
+
+  // just some additional notes here:
+  // index 3..4 is unused
+  // index 5..6 is our PM2.5 reading (3..6 is called DF1-DF4 in the datasheet at
+  // http://www.jdscompany.co.kr/download.asp?gubun=07&filename=PM1006_LED_PARTICLE_SENSOR_MODULE_SPECIFICATIONS.pdf
+  // that datasheet goes on up to DF16, which is unused for PM1006 but used in PM1006K
+  // so this code should be trivially extensible to support that one later
+  if (index < (sizeof(PM1006_RESPONSE_HEADER) + 16))
+    return true;
+
+  // checksum
+  if (index == (sizeof(PM1006_RESPONSE_HEADER) + 16)) {
+    uint8_t checksum = pm1006_checksum_(this->data_, sizeof(PM1006_RESPONSE_HEADER) + 17);
+    if (checksum != 0) {
+      ESP_LOGW(TAG, "PM1006 checksum is wrong: %02x, expected zero", checksum);
+      return false;
+    }
+    return {};
+  }
+
+  return false;
+}
+
+void PM1006Component::parse_data_() {
+  const int pm_2_5_concentration = this->get_16_bit_uint_(5);
+
+  ESP_LOGD(TAG, "Got PM2.5 Concentration: %d µg/m³", pm_2_5_concentration);
+
+  if (this->pm_2_5_sensor_ != nullptr) {
+    this->pm_2_5_sensor_->publish_state(pm_2_5_concentration);
+  }
+}
+
+uint16_t PM1006Component::get_16_bit_uint_(uint8_t start_index) const {
+  return encode_uint16(this->data_[start_index], this->data_[start_index + 1]);
+}
+
+}  // namespace pm1006
+}  // namespace esphome