external_components compile error: 'D3Sensor' was not declared in this scope

[ltvanderkrogt]

It seems like a simple error but I'm struggling to solve this problem. I am not a developer but I try to understand the external_components concept by making a new component. I looked for a "hello world" external_components example but unfortunately found nothing other than a few vague videos.
For my particulate matter sensor I made a simple Arduino code with which the sensor works perfectly. Now I would like to convert this code to esphome external_component. I made a d3_sensor.h and a d3_sensor.cpp for that and a yaml. When compiling I get these errors;

/config/esphome/fijnstof-1-x3.yaml: In lambda function:
/config/esphome/fijnstof-1-x3.yaml:39:7: error: 'D3Sensor' was not declared in this scope
   39 |       D3Sensor d3_sensor;
      |       ^~~~~~~~
/config/esphome/fijnstof-1-x3.yaml:40:31: error: 'd3_sensor' was not declared in this scope
   40 |       App.register_component(&d3_sensor);
      |                               ^~~~~~~~~

This is my yaml;

esphome:
  name: fijnstof-1
  friendly_name: Fijnstof-1
esp8266:
  board: d1_mini
api:
  encryption:
    key: 336WK4kc6*********************yFzR0D/TqrIaeiVT/4=
ota:
  password: 07aa44*********************57a3c45b96e2
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
    ssid: Fijnstof-1 Fallback Hotspot
    password: AWv2VUXNi9po
captive_portal: null
web_server: null

logger:
  level: DEBUG

uart:
  rx_pin: D1
  tx_pin: D2
  baud_rate: 9600

external_components:
  - source:
      type: local
      path: components/d3_sensor

sensor:
  - platform: custom
    lambda: |-
      D3Sensor d3_sensor;
      App.register_component(&d3_sensor);
      std::vector<esphome::sensor::Sensor*> sensors;
      sensors.push_back(d3_sensor.pm1);
      sensors.push_back(d3_sensor.pm2_5);
      sensors.push_back(d3_sensor.pm10);
      return sensors;
    sensors:
      - name: PM1.0
        unit_of_measurement: µg/m³
        accuracy_decimals: 0
      - name: PM2.5
        unit_of_measurement: µg/m³
        accuracy_decimals: 0
      - name: PM10
        unit_of_measurement: µg/m³
        accuracy_decimals: 0

d3_sensor.h

#ifndef D3_SENSOR_H
#define D3_SENSOR_H

#include <esphome.h>

namespace esphome {
namespace d3_sensor {

class D3Sensor : public Component {
 public:
  void setup() override;
  void loop() override;

 protected:
  void printValues(uint8_t data[]);
  uint16_t calculateChecksum(uint8_t data[]);

 private:
  SoftwareSerial mySerial;
};

}  // namespace d3_sensor
}  // namespace esphome

#endif  // D3_SENSOR_H

d3_sensor.cpp

#include "d3_sensor.h"

namespace esphome {
namespace d3_sensor {

void D3Sensor::setup() {
  mySerial = SoftwareSerial(14, 12);  // Replace with your RX, TX pin numbers
  mySerial.begin(9600);
}

void D3Sensor::printValues(uint8_t data[]) {
  int pm1_standard = (data[4] << 8) | data[5];
  int pm25_standard = (data[6] << 8) | data[7];
  int pm10_standard = (data[8] << 8) | data[9];

  ESP_LOGD("d3_sensor", "PM1.0: %d ug/m3, PM2.5: %d ug/m3, PM10: %d ug/m3", pm1_standard, pm25_standard, pm10_standard);
}

uint16_t D3Sensor::calculateChecksum(uint8_t data[]) {
  uint16_t checksum = 0;
  for (int i = 0; i < 30; i++) {
    checksum += data[i];
  }
  return checksum;
}

void D3Sensor::loop() {
  if (mySerial.available() >= 32) {
    if (mySerial.read() == 0x42 && mySerial.read() == 0x4D) {
      uint8_t data[32];
      for (int i = 0; i < 32; i++) {
        data[i] = mySerial.read();
      }
      uint16_t receivedChecksum = (data[30] << 8) | data[31];
      uint16_t calculatedChecksum = calculateChecksum(data);
      if (receivedChecksum == 0xFFFF || receivedChecksum == calculatedChecksum) {
        printValues(data);
      }
    }
  }
}

}  // namespace d3_sensor
}  // namespace esphome

ESPHome
Current version: 2024.3.0

Home Assistant

Core
2024.3.3
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[ssieb]

Your path has to stop at the components level as described in the docs.

[ltvanderkrogt]

I will try tomorrow to fix the discord problem. Thanks a lot for kow.

[ssieb]

Try clicking on the "why is it invalid" link. Maybe you're blocked for some reason.

[ltvanderkrogt]

Dirty cookies was not one of the invalid options but after cleaning it works for now. I used your link to login, and managed to find the esphome server and channels. I suppose I can drop my issue in #general-support?

[ssieb]

yes. Just reference this discussion, don't paste code in the channel.

[ltvanderkrogt]

thanks for your help and the tips. I will ask my sons how I should behave further on Discord. 😅