Revision 1:932d451474dc, committed 2014-04-19

Comitter:

moisesmarangoni

Date:

Sat Apr 19 18:05:38 2014 +0000

Parent:

0:9b5b3200688f

Commit message:

First realease DHT working with Nucleo Board. Thanks (Somlak Mangnimit)

Changed in this revision

diff -r 9b5b3200688f -r 932d451474dc DHT.cpp
--- a/DHT.cpp	Mon Jul 09 19:47:43 2012 +0000
+++ b/DHT.cpp	Sat Apr 19 18:05:38 2014 +0000
@@ -1,233 +1,134 @@
 /*
  *  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
+ *  Works with DHT11, DHT22 Nucleo Board tested on F103RB
  *
- *  Copyright (C) Wim De Roeve
+ *  Copyright (C) Wim De Roeve 
+ *                ported to work on Nucleo Board:
+ *                                              Moises Marangoni
+ *                                              Somlak Mangnimit
  *                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"
+#include "mbed.h"
 
 #define DHT_DATA_BIT_COUNT 41
 
+//DigitalInOut data_pin(PA_10);
+
 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];
+    Timer tmr;
+    DigitalInOut data_pin(_pin);
+    // BUFFER TO RECEIVE
+    //uint8_t bits[5];
+    uint8_t cnt = 7;
+    uint8_t idx = 0;
+    
+    tmr.stop();
+    tmr.reset();
 
-    eError err = ERROR_NONE;
-    time_t currentTime = time(NULL);
-
-    DigitalInOut DHT_io(_pin);
+    // EMPTY BUFFER
+    for(int i=0; i< 5; i++) bits[i] = 0;
 
-    for (i = 0; i < DHT_DATA_BIT_COUNT; i++) {
-        bitTimes[i] = 0;
-    }
+    // REQUEST SAMPLE
+    data_pin.output();
+    data_pin.write(0);
+    wait_ms(18);
+    data_pin.write(1);
+    wait_us(40);
+    data_pin.input();
 
-    if (!_firsttime) {
-        if (int(currentTime - _lastReadTime) < 2) {
-            err = ERROR_NO_PATIENCE;
-            return err;
-        }
-    } else {
-        _firsttime=false;
-        _lastReadTime=currentTime;
-    }
-    retryCount = 0;
+    // ACKNOWLEDGE or TIMEOUT
+    unsigned int loopCnt = 10000;
+    
+    while(!data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
 
-    do {
-        if (retryCount > 125) {
-            err = BUS_BUSY;
-            return err;
-        }
-        retryCount ++;
-        wait_us(2);
-    } while ((DHT_io==0));
+    loopCnt = 10000;
+    
+    while(data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
 
+    // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT
+    for(int i=0; i<40; i++){
+        
+        loopCnt = 10000;
+        
+        while(!data_pin.read())if(loopCnt-- == 0)return DHTLIB_ERROR_TIMEOUT;
+
+        //unsigned long t = micros();
+        tmr.start();
 
-    DHT_io.output();
-    DHT_io = 0;
-    wait_ms(18);
-    DHT_io = 1;
-    wait_us(40);
-    DHT_io.input();
+        loopCnt = 10000;
+        
+        while(data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
 
-    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;
+        if(tmr.read_us() > 40) bits[idx] |= (1 << cnt);
+        
+        tmr.stop();
+        tmr.reset();
+        
+        if(cnt == 0){   // next byte?
+        
+            cnt = 7;    // restart at MSB
+            idx++;      // next byte!
+            
+        }else cnt--;
+        
     }
-
-    wait_us(80);
-
-    for (i = 0; i < 5; i++) {
-        for (j = 0; j < 8; j++) {
+    // WRITE TO RIGHT VARS
+    // as bits[1] and bits[3] are allways zero they are omitted in formulas.
+    //humidity    = bits[0]; 
+    //temperature = bits[2]; 
 
-            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;
+    uint8_t sum = bits[0] + bits[2];  
 
-            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;
-
+    if(bits[4] != sum)return DHTLIB_ERROR_CHECKSUM;
+    
+    return DHTLIB_OK;
 }
-
-float DHT::CalcTemperature() {
-    int v;
+float DHT::ReadTemperature() {
+    //int retornotemp;
 
     switch (_DHTtype) {
         case DHT11:
-            v = DHT_data[2];
-            return float(v);
+            temperature = bits[2];
+            return float(temperature);
         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);
+            temperature = bits[2] & 0x7F;
+            temperature *= 256;
+            temperature += bits[3];
+            temperature /= 10;
+           if (bits[2] & 0x80)
+            {temperature *= -1;}
+            return float(temperature);
     }
     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;
+int DHT::ReadHumidity() {
+    //int v;
 
     switch (_DHTtype) {
         case DHT11:
-            v = DHT_data[0];
-            return float(v);
+            humidity = bits[0];
+            return float(humidity);
         case DHT22:
-            v = DHT_data[0];
-            v *= 256;
-            v += DHT_data[1];
-            v /= 10;
-            return float(v);
+            humidity = bits[0];
+            humidity *= 256;
+            humidity += bits[1];
+            humidity /= 10;
+            return float(humidity);
     }
     return 0;
-}
-
-
+}
\ No newline at end of file

diff -r 9b5b3200688f -r 932d451474dc DHT.h
--- a/DHT.h	Mon Jul 09 19:47:43 2012 +0000
+++ b/DHT.h	Sat Apr 19 18:05:38 2014 +0000
@@ -1,33 +1,14 @@
-/* 
- *  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)
+/*
+ *  DHT Library for  Digital-output Humidity and Temperature sensors
  *
- *  Copyright (C) Wim De Roeve
- *                based on DHT22 sensor library by HO WING KIT
- *                Arduino DHT11 library
+ *  Works with DHT11, DHT22 Nucleo Board tested on F103RB
  *
- * 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.
+ *  Copyright (C) Wim De Roeve 
+ *                ported to work on Nucleo Board:
+ *                                                Moises Marangoni
+ *                                                Somlak Mangnimit
+ *                based on DHT22 sensor library by HO WING KIT
+ *                Arduino DHT11 library 
  */
 
 #ifndef MBED_DHT_H
@@ -37,58 +18,33 @@
 
 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:
 
+#define DHTLIB_OK                0
+#define DHTLIB_ERROR_CHECKSUM   -1
+#define DHTLIB_ERROR_TIMEOUT    -2
+
     DHT(PinName pin,int DHTtype);
     ~DHT();
+    uint8_t bits[5];
     int readData(void);
-    float ReadHumidity(void);
-    float ReadTemperature(eScale Scale);
-    float CalcdewPoint(float celsius, float humidity);
-    float CalcdewPointFast(float celsius, float humidity);
+    int ReadHumidity(void);
+    float ReadTemperature(void);
+    int humidity;
+    float temperature;
+    Timer tmr;
 
 private:
-    time_t  _lastReadTime;
-    float _lastTemperature;
-    float _lastHumidity;
+    //time_t  _lastReadTime;
     PinName _pin;
-    bool _firsttime;
     int _DHTtype;
     int DHT_data[6];
-    float CalcTemperature();
-    float CalcHumidity();
-    float ConvertCelciustoFarenheit(float);
-    float ConvertCelciustoKelvin(float);
-
+    //DigitalInOut data_pin(_pin);
 };
 
 #endif