DHT.h

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/*
 *  DHT Library for  Digital-output Humidity and Temperature sensors
 *
 *  Works with DHT11, DHT21, DHT22
 *             SEN11301P,  Grove - Temperature&Humidity Sensor     (Seeed Studio)
 *             SEN51035P,  Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
 *             AM2302   ,  temperature-humidity sensor
 *             RHT01,RHT02, RHT03    ,  Humidity and Temperature Sensor         (Sparkfun)
 *
 *  Copyright (C) Wim De Roeve
 *                based on DHT22 sensor library by HO WING KIT
 *                Arduino DHT11 library
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documnetation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to  whom the Software is
 * furished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
 
#ifndef MBED_DHT_H
#define MBED_DHT_H
 
#include "mbed.h"
 
enum eType
{
  DHT11     = 11,
  SEN11301P = 11,
  RHT01     = 11,
  DHT22     = 22,
  AM2302    = 22,
  SEN51035P = 22,
  RHT02     = 22,
  RHT03     = 22
};
typedef enum eType eType;
 
enum eError
{
  ERROR_NONE = 0,
  BUS_BUSY,
  ERROR_NOT_PRESENT,
  ERROR_ACK_TOO_LONG,
  ERROR_SYNC_TIMEOUT,
  ERROR_DATA_TIMEOUT,
  ERROR_CHECKSUM,
  ERROR_NO_PATIENCE
};
typedef enum eError eError;
 
enum eScale
{
  CELCIUS = 0,
  FARENHEIT,
  KELVIN
};
typedef enum eScale eScale;
 
 
class DHT
{
 
public:
 
  DHT(PinName pin, eType DHTtype);
  ~DHT();
  eError readData(void);
  float ReadHumidity(void);
  float ReadTemperature(eScale const Scale);
  float CalcdewPoint(float const celsius, float const humidity);
  float CalcdewPointFast(float const celsius, float const humidity);
 
private:
  time_t  _lastReadTime;
  float _lastTemperature;
  float _lastHumidity;
  PinName _pin;
  bool _firsttime;
  eType _DHTtype;
  uint8_t DHT_data[5];
  float CalcTemperature();
  float CalcHumidity();
  float ConvertCelciustoFarenheit(float const);
  float ConvertCelciustoKelvin(float const);
  eError stall(DigitalInOut &io, int const level, int const max_time);
 
};
 
#endif