Dust sensor and TTGO ESP32 LoRa V2 1.6

[darelg]

Good evening dear. I am new to the Arduino world, I am trying to create a system in which measurements can be made with the GP2Y1010AU0F dust sensor connected to a TTGO ESP32 LoRa V2 1.6 to be able to send the data to another ESP32 LoRa; But in the code I have an error ('pm' was not declared in this scope). Please if you help me correct my code or give me advice.
Beforehand thank you very much.
Best regards.

1. #include <SPI.h>

2. #include <LoRa.h>

3. /* Connect to SHARP PM2.5 Sensor*/

4. #include <PMsensor.h>

5. PMsensor PM;

6. #define LEDPOWER 12 //pin where the SHARP is connected

7. #define MEASUREPIN 36 //pin where the SHARP is connected

8. //define the pins used by the LoRa transceiver module

9. #define SCLK 5

10. #define MISO 19

11. #define MOSI 27

12. #define CS 18

13. #define RST 23

14. #define DIO 26

15. #define BAND 915E6 //433E6 for Asia, 866E6 for Europe, 915E6 for North America

16. //packet counter

17. int readingID = 0;

18. int counter = 0;

19. String LoRaMessage = "";

20. //Initialize LoRa module

21. void startLoRA()

22. {

23. LoRa.setPins(CS, RST, DIO); //setup LoRa transceiver module

24. while (!LoRa.begin(BAND) && counter < 10) {

25. Serial.print(".");
    

26. counter++;
    

27. delay(500);
    

28. }

29. if (counter == 10)

30. {

31. // Increment readingID on every new reading
    

32. readingID++;
    

33. Serial.println("Starting LoRa failed!");
    

34. }

35. Serial.println("LoRa Initialization OK!");

36. delay(2000);

37. }

38. void startPMsensor()

39. {

40. if (isnan(pm))

41. {

42. Serial.println("Failed to read from SHARP sensor!");
    

43. return;
    

44. }

45. }

//EN ESTA PARTE ES QUE ME SALE EL ERROR.//

46. void getReadings() {

47.  float pm = 0;
    

48.  int err = pmsensorErrSuccess;
    

49.  if ((err = pm.read(&pm, true, 0.1)) != pmsensorErrSuccess) { 
    

50.  Serial.print("data Error = ");
    

51.  Serial.println(err);
    

52.  return;
    

53. }

54. Serial.print("PM2.5: ");

55. Serial.print(pm);

56. Serial.println(" ppm");

57. }

58. void sendReadings() {

59. LoRaMessage = String(readingID) + "/" + String(pm) ;

60. //Send LoRa packet to receiver

61. LoRa.beginPacket();

62. LoRa.print(LoRaMessage);

63. LoRa.endPacket();

64. Serial.print("Sending packet: ");

65. Serial.println(readingID);

66. readingID++;

67. Serial.println(LoRaMessage);

68. }

69. void setup() {

70. //initialize Serial Monitor

71. Serial.begin(115200);

72. PMsensor.begin();

73. startPMsensor();

74. startLoRA();

75. }

76. void loop() {

77. getReadings();

78. sendReadings();

79. delay(500);

80. }

[anon73444976]

PM is not the same thing as pm.

C++ is case-sensitive.

Please remember to use code tags when posting code AND all of your error messages.

float pm = 0;
 int err = pmsensorErrSuccess;
 if ((err = pm.read(

Here, the compiler will probably mention something about "read" not being defined for objects of type float.

[darelg]

Thanks for your comments, indeed I have an error, request for member 'read' in 'pm', which is of non-class type 'float'

 float pm = 0;
  int err = PMsensorErrSuccess;
  
  if ((err = pm.read(&pm, true, 0.1)) != PMsensorErrSuccess) {
    Serial.print("data Error = ");
    Serial.println(err);
    return;

[anon73444976]

@darelg

PMsensor PM;

 if ((err = PM.read(&pm, 

etc?