DHT-sensor-library/DHT.h

/*!
 *  @file DHT.h
 *
 *  This is a library for DHT series of low cost temperature/humidity sensors.
 *
 *  You must have Adafruit Unified Sensor Library library installed to use this class.
 *
 *  Adafruit invests time and resources providing this open source code,
 *  please support Adafruit andopen-source hardware by purchasing products
 *  from Adafruit!
 *
 *  Written by Adafruit Industries.
 *
 *  MIT license, all text above must be included in any redistribution
 */

#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. */
#define DHT11 11 /**< DHT TYPE 11 */
#define DHT12 12 /**< DHY TYPE 12 */
#define DHT22 22 /**< DHT TYPE 22 */
#define DHT21 21 /**< DHT TYPE 21 */
#define AM2301 21 /**< AM2301 */

/*! 
 *  @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