ThingSpeak

I'm neither sure about the dht syntax. Previously I had it as

float number1 = dht.temperature().getSensor(&sensor);
float number1 = dht.humidity().getSensor(&sensor);

but the compiler would always return an apparently insurmountable error message as follows: "void value not ignored as it ought to be." For some reason, I got it through when I changed the "sensors" to "events". However, the "events" appear to give me only the value of 1. And they seem to do so irrespective of whether the commands are inside the loop or not.

I have two DHT libraries in my .arduino15/libraries -folder. I suspect that either one of them contains the syntax of the DHT11 sensor for temperature and humidity. I have tried the following:

• dht.readTemperature() and dht.readHumidity(): "class 'DHT_Unified' has no member named 'readTemperature'; did you mean 'Temperature'?
• dht.temperature() and dht.humidity(): "cannot convert 'DHT_Unified::Temperature' to 'int' in initialization (or float if I use float)
• dht.temperature().getSensor(&sensor) and dht.humidity().getSensor(&sensor): "void value not ignored as it ought to be",
• dht.temperature().getEvent(&event) and dht.temperature().getEvent(&event): ran okay but resulted in the values of 1 at Thingspeak.

I think the secret for the correct syntax for getting the sensor measurements must lie somewhere in these libraries:

DHT.h: #ifndef DHT_H #define DHT_H

#include "Arduino.h"

/* Uncomment to enable printing out nice debug messages. */
//#define DHT_DEBUG

#define DEBUG_PRINTER                                                          \
  Serial /**< Define where debug output will be printed.                       \
          */

/* Setup debug printing macros. */
#ifdef DHT_DEBUG
#define DEBUG_PRINT(...)                                                       \
  { DEBUG_PRINTER.print(__VA_ARGS__); }
#define DEBUG_PRINTLN(...)                                                     \
  { DEBUG_PRINTER.println(__VA_ARGS__); }
#else
#define DEBUG_PRINT(...)                                                       \
  {} /**< Debug Print Placeholder if Debug is disabled */
#define DEBUG_PRINTLN(...)                                                     \
  {} /**< Debug Print Line Placeholder if Debug is disabled */
#endif

/* Define types of sensors. */
static const uint8_t DHT11{11};  /**< DHT TYPE 11 */
static const uint8_t DHT12{12};  /**< DHY TYPE 12 */
static const uint8_t DHT21{21};  /**< DHT TYPE 21 */
static const uint8_t DHT22{22};  /**< DHT TYPE 22 */
static const uint8_t AM2301{21}; /**< AM2301 */

#if defined(TARGET_NAME) && (TARGET_NAME == ARDUINO_NANO33BLE)
#ifndef microsecondsToClockCycles
/*!
 * As of 7 Sep 2020 the Arduino Nano 33 BLE boards do not have
 * microsecondsToClockCycles defined.
 */
#define microsecondsToClockCycles(a) ((a) * (SystemCoreClock / 1000000L))
#endif
#endif

/*!
 *  @brief  Class that stores state and functions for DHT
 */
class DHT {
public:
  DHT(uint8_t pin, uint8_t type, uint8_t count = 6);
  void begin(uint8_t usec = 55);
  float readTemperature(bool S = false, bool force = false);
  float convertCtoF(float);
  float convertFtoC(float);
  float computeHeatIndex(bool isFahrenheit = true);
  float computeHeatIndex(float temperature, float percentHumidity,
                         bool isFahrenheit = true);
  float readHumidity(bool force = false);
  bool read(bool force = false);

private:
  uint8_t data[5];
  uint8_t _pin, _type;
#ifdef __AVR
  // Use direct GPIO access on an 8-bit AVR so keep track of the port and
  // bitmask for the digital pin connected to the DHT.  Other platforms will use
  // digitalRead.
  uint8_t _bit, _port;
#endif
  uint32_t _lastreadtime, _maxcycles;
  bool _lastresult;
  uint8_t pullTime; // Time (in usec) to pull up data line before reading

    uint32_t expectPulse(bool level);
  };

/*!
 *  @brief  Class that defines Interrupt Lock Avaiability
 */
class InterruptLock {
public:
  InterruptLock() {
#if !defined(ARDUINO_ARCH_NRF52)
    noInterrupts();
#endif
  }
  ~InterruptLock() {
#if !defined(ARDUINO_ARCH_NRF52)
    interrupts();
#endif
  }
};

#endif

DHT_U.h:

#ifndef DHT_U_H
#define DHT_U_H

#include <Adafruit_Sensor.h>
#include <DHT.h>

#define DHT_SENSOR_VERSION 1 /**< Sensor Version */

/*!
 *  @brief  Class that stores state and functions for interacting with
 * DHT_Unified.
 */
class DHT_Unified {
public:
  DHT_Unified(uint8_t pin, uint8_t type, uint8_t count = 6,
              int32_t tempSensorId = -1, int32_t humiditySensorId = -1);
  void begin();

    /*!
     *  @brief  Class that stores state and functions about Temperature
     */
    class Temperature : public Adafruit_Sensor {
    public:
      Temperature(DHT_Unified *parent, int32_t id);
      bool getEvent(sensors_event_t *event);
      void getSensor(sensor_t *sensor);

    private:
      DHT_Unified *_parent;
      int32_t _id;
    };

    /*!
     *  @brief  Class that stores state and functions about Humidity
     */
    class Humidity : public Adafruit_Sensor {
    public:
      Humidity(DHT_Unified *parent, int32_t id);
      bool getEvent(sensors_event_t *event);
      void getSensor(sensor_t *sensor);

    private:
      DHT_Unified *_parent;
      int32_t _id;
    };

    /*!
     *  @brief  Returns temperature stored in _temp
     *  @return Temperature value
     */
    Temperature temperature() { return _temp; }

    /*!
     *  @brief  Returns humidity stored in _humidity
     *  @return Humidity value
     */
    Humidity humidity() { return _humidity; }

private:
  DHT _dht;
  uint8_t _type;
  Temperature _temp;
  Humidity _humidity;

    void setName(sensor_t *sensor);
    void setMinDelay(sensor_t *sensor);
  };

#endif