Library for DHT22/RHT03 Temperature and Humidity Sensor
DHT22.h
- Committer:
- crazystick
- Date:
- 2012-03-29
- Revision:
- 0:42ffca439fcc
File content as of revision 0:42ffca439fcc:
/* mbed DHT22 Library * Copyright (c) 2011, sford, http://mbed.org * * 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_DHT22_H #define MBED_DHT22_H #include "mbed.h" /** * Currently supports DHT22 (SparkFun Electronics) * Humidity and Temperature Sensor * * Features: * > 3.3-6V Input * > 1-1.5mA measuring current * > 40-50uA standby current * > Humidity from 0-100% RH * > -40 - 80 degrees C temperature range * > +-2% RH accuracy * > +-0.5 degrees C * * Usages * #include "DHT22.h" * * DTH22 dth22(PinName sda, PinName scl, int addr); // pin * * int main() { * err=dth22.readData(); * if (err==0) { printf("Temperature is %f.2 C\n",dht22.getTemperature()); printf("Humidity is %f.2 \%\n",dht22.getHumidity()); } * * */ #define DHT22_ERROR_VALUE -99.5 typedef enum { DHT_ERROR_NONE = 0, DHT_BUS_HUNG, DHT_ERROR_NOT_PRESENT, DHT_ERROR_ACK_TOO_LONG, DHT_ERROR_SYNC_TIMEOUT, DHT_ERROR_DATA_TIMEOUT, DHT_ERROR_CHECKSUM, DHT_ERROR_TOO_QUICK } DHT22_ERROR; class DHT22 { private: time_t _lastReadTime; PinName _data; float _lastHumidity; float _lastTemperature; public: DHT22(PinName Data); ~DHT22(); DHT22_ERROR readData(void); float getHumidity(); float getTemperatureC(); void clockReset(); }; #endif /*_DHT22_H_*/