HO WING KIT
=DHT22 Temperature and Humidity Sensor= The DHT-22 is a low cost humidity and temperature sensor with a single wire digital interface. The sensor is calibrated and doesn\\\'t require extra components so you can get right to measuring relative humidity and temperature. [[http://dlnmh9ip6v2uc.cloudfront.net/images/products/10167-01_i_ma.jpg]] Features: * 3.3-6V Input * 1-1.5mA measuring current * 40-50 uA standby current * Humidity from 0-100% RH * -40 - 80 degrees C temperature range * +-2% RH accuracy * +-0.5 degrees C ***(same as RHT03 www.humiditycn.com)*** Available as http://www.sparkfun.com/products/10167 | DHT22(pin) | Function | mbed | | 1 - VDD | VDD-power supply (3.3-6V) | (Vout) 5V | | 2 - DATA | Single pin signal | p15 | | 3 - NULL | | | | 4 - GND | Connect to ground | GND | == Library == <<library /users/hwkit/libraries/DHT22/latest/docs/DHT22_8h_source.html>> <<library users=\"\" hwkit=\"\" libraries=\"\" dht22=\"\" latest=\"\" docs=\"\" dht22_8cpp_source.html=\"\">></library>
Diff: DHT22.h
- Revision:
- 0:547e68daeb1b
- Child:
- 1:5b20ff4fd227
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT22.h Tue Jun 21 03:44:05 2011 +0000
@@ -0,0 +1,84 @@
+/* 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();
+ *
+ *
+ */
+
+#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_TOOQUICK
+} DHT22_ERROR;
+
+class DHT22 {
+private:
+ uint8_t _bitmask;
+ volatile uint8_t *_baseReg;
+ time_t _lastReadTime;
+ PinName _vcc, _data;
+ int m_addr;
+ float _lastHumidity;
+ float _lastTemperature;
+
+public:
+ DHT22(PinName Data);
+ ~DHT22();
+ DHT22_ERROR readData(void);
+ float getHumidity();
+ float getTemperatureC();
+ void clockReset();
+};
+
+#endif /*_DHT22_H_*/