DHT.h

00001 /*
00002  *  DHT Library for  Digital-output Humidity and Temperature sensors
00003  *
00004  *  Works with DHT11, DHT21, DHT22
00005  *             SEN11301P,  Grove - Temperature&Humidity Sensor     (Seeed Studio)
00006  *             SEN51035P,  Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
00007  *             AM2302   ,  temperature-humidity sensor
00008  *             RHT01,RHT02, RHT03    ,  Humidity and Temperature Sensor         (Sparkfun)
00009  *
00010  *  Copyright (C) Wim De Roeve
00011  *                based on DHT22 sensor library by HO WING KIT
00012  *                Arduino DHT11 library
00013  *
00014  * Permission is hereby granted, free of charge, to any person obtaining a copy
00015  * of this software and associated documnetation files (the "Software"), to deal
00016  * in the Software without restriction, including without limitation the rights
00017  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00018  * copies of the Software, and to permit persons to  whom the Software is
00019  * furished to do so, subject to the following conditions:
00020  *
00021  * The above copyright notice and this permission notice shall be included in
00022  * all copies or substantial portions of the Software.
00023  *
00024  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00025  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00026  * FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00027  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00028  * LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00029  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00030  * THE SOFTWARE.
00031  */
00032 
00033 #ifndef MBED_DHT_H
00034 #define MBED_DHT_H
00035 
00036 #include "mbed.h"
00037 
00038 typedef enum eType eType;
00039 enum eType {
00040     DHT11     = 11,
00041     SEN11301P = 11,
00042     RHT01     = 11,
00043     DHT22     = 22,
00044     AM2302    = 22,
00045     SEN51035P = 22,
00046     RHT02     = 22,
00047     RHT03     = 22
00048 };
00049 
00050 typedef enum eError eError;
00051 enum eError {
00052     ERROR_NONE = 0,
00053     BUS_BUSY,
00054     ERROR_NOT_PRESENT,
00055     ERROR_ACK_TOO_LONG,
00056     ERROR_SYNC_TIMEOUT,
00057     ERROR_DATA_TIMEOUT,
00058     ERROR_CHECKSUM,
00059     ERROR_NO_PATIENCE
00060 };
00061 
00062 typedef enum eScale eScale;
00063 enum eScale {
00064     CELCIUS = 0,
00065     FARENHEIT,
00066     KELVIN
00067 };
00068 
00069 
00070 class DHT
00071 {
00072 
00073 public:
00074 
00075     DHT(PinName pin, eType DHTtype);
00076     ~DHT();
00077     eError readData(void);
00078     float ReadHumidity(void);
00079     float ReadTemperature(eScale const Scale);
00080     float CalcdewPoint(float const celsius, float const humidity);
00081     float CalcdewPointFast(float const celsius, float const humidity);
00082 
00083 private:
00084     time_t  _lastReadTime;
00085     float _lastTemperature;
00086     float _lastHumidity;
00087     PinName _pin;
00088     bool _firsttime;
00089     eType _DHTtype;
00090     uint8_t DHT_data[5];
00091     float CalcTemperature();
00092     float CalcHumidity();
00093     float ConvertCelciustoFarenheit(float const);
00094     float ConvertCelciustoKelvin(float const);
00095     eError stall(DigitalInOut &io, int const level, int const max_time);
00096 
00097 };
00098 
00099 #endif