test

Dependents:   gather_sensor_data

Files at this revision

API Documentation at this revision

Comitter:
readysteadygo2006
Date:
Thu Sep 08 14:05:43 2016 +0000
Commit message:
test

Changed in this revision

DHT.cpp Show annotated file Show diff for this revision Revisions of this file
DHT.h Show annotated file Show diff for this revision Revisions of this file
diff -r 000000000000 -r 1570961902a8 DHT.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT.cpp	Thu Sep 08 14:05:43 2016 +0000
@@ -0,0 +1,234 @@
+/*
+ *  DHT Library for  Digital-output Humidity and Temperature sensors
+ *
+ *  Works with DHT11, DHT22
+ *             SEN11301P,  Grove - Temperature&Humidity Sensor     (Seeed Studio)
+ *             SEN51035P,  Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
+ *             AM2302   ,  temperature-humidity sensor
+ *             HM2303   ,  Digital-output humidity and temperature sensor
+ *
+ *  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.
+ */
+
+#include "DHT.h"
+
+#define DHT_DATA_BIT_COUNT 41
+
+DHT::DHT(PinName pin,int DHTtype) {
+    _pin = pin;
+    _DHTtype = DHTtype;
+    _firsttime=true;
+}
+
+DHT::~DHT() {
+}
+
+int DHT::readData() {
+    int i, j, retryCount,b;
+    unsigned int bitTimes[DHT_DATA_BIT_COUNT];
+
+    eError err = ERROR_NONE;
+    time_t currentTime = time(NULL);
+
+//    DigitalInOut DHT_io(_pin);
+      DigitalInOut DHT_io(PA_10);
+
+    for (i = 0; i < DHT_DATA_BIT_COUNT; i++) {
+        bitTimes[i] = 0;
+    }
+
+    if (!_firsttime) {
+        if (int(currentTime - _lastReadTime) < 2) {
+            err = ERROR_NO_PATIENCE;
+            return err;
+        }
+    } else {
+        _firsttime=false;
+        _lastReadTime=currentTime;
+    }
+    retryCount = 0;
+
+    do {
+        if (retryCount > 125) {
+            err = BUS_BUSY;
+            return err;
+        }
+        retryCount ++;
+        wait_us(2);
+    } while ((DHT_io==0));
+
+
+    DHT_io.output();
+    DHT_io = 0;
+    wait_ms(18);
+    DHT_io = 1;
+    wait_us(40);
+    DHT_io.input();
+
+    retryCount = 0;
+    do {
+        if (retryCount > 40)  {
+            err = ERROR_NOT_PRESENT;
+            return err;
+        }
+        retryCount++;
+        wait_us(1);
+    } while ((DHT_io==1));
+
+    if (err != ERROR_NONE) {
+        return err;
+    }
+
+    wait_us(80);
+
+    for (i = 0; i < 5; i++) {
+        for (j = 0; j < 8; j++) {
+
+            retryCount = 0;
+            do {
+                if (retryCount > 75)  {
+                    err = ERROR_DATA_TIMEOUT;
+                    return err;
+                }
+                retryCount++;
+                wait_us(1);
+            } while (DHT_io == 0);
+            wait_us(40);
+            bitTimes[i*8+j]=DHT_io;
+
+            int count = 0;
+            while (DHT_io == 1 && count < 100) {
+                wait_us(1);
+                count++;
+            }
+        }
+    }
+    DHT_io.output();
+    DHT_io = 1;
+    for (i = 0; i < 5; i++) {
+        b=0;
+        for (j=0; j<8; j++) {
+            if (bitTimes[i*8+j+1] > 0) {
+                b |= ( 1 << (7-j));
+            }
+        }
+        DHT_data[i]=b;
+    }
+
+    if (DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]) & 0xFF)) {
+        _lastReadTime = currentTime;
+        _lastTemperature=CalcTemperature();
+        _lastHumidity=CalcHumidity();
+
+    } else {
+        err = ERROR_CHECKSUM;
+    }
+
+    return err;
+
+}
+
+float DHT::CalcTemperature() {
+    int v;
+
+    switch (_DHTtype) {
+        case DHT11:
+            v = DHT_data[2];
+            return float(v);
+        case DHT22:
+            v = DHT_data[2] & 0x7F;
+            v *= 256;
+            v += DHT_data[3];
+            v /= 10;
+            if (DHT_data[2] & 0x80)
+                v *= -1;
+            return float(v);
+    }
+    return 0;
+}
+
+float DHT::ReadHumidity() {
+    return _lastHumidity;
+}
+
+float DHT::ConvertCelciustoFarenheit(float celsius) {
+    return celsius * 9 / 5 + 32;
+}
+
+float DHT::ConvertCelciustoKelvin(float celsius) {
+    return celsius + 273.15;
+}
+
+// dewPoint function NOAA
+// reference: http://wahiduddin.net/calc/density_algorithms.htm
+float DHT::CalcdewPoint(float celsius, float humidity) {
+    float A0= 373.15/(273.15 + celsius);
+    float SUM = -7.90298 * (A0-1);
+    SUM += 5.02808 * log10(A0);
+    SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
+    SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
+    SUM += log10(1013.246);
+    float VP = pow(10, SUM-3) * humidity;
+    float T = log(VP/0.61078);   // temp var
+    return (241.88 * T) / (17.558-T);
+}
+
+// delta max = 0.6544 wrt dewPoint()
+// 5x faster than dewPoint()
+// reference: http://en.wikipedia.org/wiki/Dew_point
+float DHT::CalcdewPointFast(float celsius, float humidity)
+{
+        float a = 17.271;
+        float b = 237.7;
+        float temp = (a * celsius) / (b + celsius) + log(humidity/100);
+        float Td = (b * temp) / (a - temp);
+        return Td;
+}
+
+float DHT::ReadTemperature(eScale Scale) {
+    if (Scale == FARENHEIT)
+        return ConvertCelciustoFarenheit(_lastTemperature);
+    else if (Scale == KELVIN)
+        return ConvertCelciustoKelvin(_lastTemperature);
+    else
+        return _lastTemperature;
+}
+
+float DHT::CalcHumidity() {
+    int v;
+
+    switch (_DHTtype) {
+        case DHT11:
+            v = DHT_data[0];
+            return float(v);
+        case DHT22:
+            v = DHT_data[0];
+            v *= 256;
+            v += DHT_data[1];
+            v /= 10;
+            return float(v);
+    }
+    return 0;
+}
+
+
diff -r 000000000000 -r 1570961902a8 DHT.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT.h	Thu Sep 08 14:05:43 2016 +0000
@@ -0,0 +1,94 @@
+/* 
+ *  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
+    } ;
+
+enum eError {
+    ERROR_NONE = 0,
+    BUS_BUSY =1,
+    ERROR_NOT_PRESENT =2 ,
+    ERROR_ACK_TOO_LONG =3 ,
+    ERROR_SYNC_TIMEOUT = 4,
+    ERROR_DATA_TIMEOUT =5 ,
+    ERROR_CHECKSUM = 6,
+    ERROR_NO_PATIENCE =7
+} ;
+
+typedef enum {
+    CELCIUS =0 ,
+    FARENHEIT =1,
+    KELVIN=2
+} eScale;
+
+
+class DHT {
+
+public:
+
+    DHT(PinName pin,int DHTtype);
+    ~DHT();
+    int readData(void);
+    float ReadHumidity(void);
+    float ReadTemperature(eScale Scale);
+    float CalcdewPoint(float celsius, float humidity);
+    float CalcdewPointFast(float celsius, float humidity);
+
+private:
+    time_t  _lastReadTime;
+    float _lastTemperature;
+    float _lastHumidity;
+    PinName _pin;
+    bool _firsttime;
+    int _DHTtype;
+    int DHT_data[6];
+    float CalcTemperature();
+    float CalcHumidity();
+    float ConvertCelciustoFarenheit(float);
+    float ConvertCelciustoKelvin(float);
+
+};
+
+#endif