dht.h

//
//    FILE: dht.h
//  AUTHOR: Rob Tillaart
// VERSION: 0.2.4
// PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
//     URL: https://github.com/RobTillaart/Arduino/tree/master/libraries/DHTstable
//
// HISTORY:
// see dht.cpp file
//

#ifndef dht_h
#define dht_h

#if ARDUINO < 100
#include <WProgram.h>
#else
#include <Arduino.h>
#endif

#define DHT_LIB_VERSION "0.2.3 - dhtstable"

const int DHTLIB_OK              = 0;
const int DHTLIB_ERROR_CHECKSUM  = -1;
const int DHTLIB_ERROR_TIMEOUT   = -2;
const int DHTLIB_INVALID_VALUE   = -999;

const int DHTLIB_DHT11_WAKEUP    = 18;
const int DHTLIB_DHT_WAKEUP      = 1;

// max timeout is 100usec.
// For a 16Mhz proc that is max 1600 clock cycles
// loops using TIMEOUT use at least 4 clock cycli
// so 100 us takes max 400 loops
// so by dividing F_CPU by 40000 we "fail" as fast as possible
const int DHTLIB_TIMEOUT = (F_CPU/40000);

class dht
{
public:
    // return values:
    // DHTLIB_OK
    // DHTLIB_ERROR_CHECKSUM
    // DHTLIB_ERROR_TIMEOUT
    int read11(uint8_t pin);      // DHT11 & DHT12
    int read(uint8_t pin);        // DHT22

    inline int read12(uint8_t pin)   { return read11(pin); }; // ok
    inline int read21(uint8_t pin)   { return read(pin); };   // ok
    inline int read22(uint8_t pin)   { return read(pin); };   // ok
    inline int read33(uint8_t pin)   { return read(pin); };   // ok
    inline int read44(uint8_t pin)   { return read(pin); };   // ok
    inline int read2301(uint8_t pin) { return read(pin); };   // ok
    inline int read2302(uint8_t pin) { return read(pin); };   // ok
    inline int read2320(uint8_t pin) { return read(pin); };   //.ok
    inline int read2322(uint8_t pin) { return read(pin); };   // ok

    float humidity;
    float temperature;

    bool getDisableIRQ()              { return _disableIRQ; };
    void setDisableIRQ(bool b )       { _disableIRQ = b; };

private:
    uint8_t bits[5];  // buffer to receive data
    int     _readSensor(uint8_t pin, uint8_t wakeupDelay);
    bool    _disableIRQ = false;
};
#endif
//
// END OF FILE
//