Revision 4:02a922030bc3, committed 2016-01-07

Comitter:

emcu

Date:

Thu Jan 07 00:29:30 2016 +0000

Parent:

3:f483abe4bc57

Commit message:

NUCLEO-F401RE + DS18B20 + Thermistor; Thermistor (NTC) of 10K - For calculate the temperature we use the Steinhart-Hart equation.;

Changed in this revision

diff -r f483abe4bc57 -r 02a922030bc3 main.cpp
--- a/main.cpp	Sat Feb 28 15:07:09 2015 +0000
+++ b/main.cpp	Thu Jan 07 00:29:30 2016 +0000
@@ -1,6 +1,85 @@
+
+/**
+
+    NUCLEO-F401RE + DS18B20 + Thermistor
+    Thermistor response, not fully tested.
+
+By:       www.emcu.it
+Date:     Jan.2015
+Version:  1.0
+Name:     NUCLEO-F401RE-DS1820andThermistorNTC10K
+NOTE:     For more info see here: http://www.emcu.it/NUCLEOevaBoards/mBed/QSG-Mbed-Library.pdf
+
+THE SOFTWARE AND HARDWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. 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.
+
+UART Configuration (It is necessary for see the results, we suggest to use TeraTerm on PC)  
+    Baud Rate:    9600 
+    Data Bit:     8
+    Parity:       NONE
+    Stop Bit:     1
+    Flow Control: NONE
+    
+This SW is ready to use on the NUCLEO-F334R8.
+Connect to the NUCLEO-F334R8 the DS18B20 sensor (see the schematic below).
+The temperature sampling time is 1 sec.
+
+ DS18B20 front view
+    __________
+   |          |
+   |    DS    |
+   |   18B20  |   
+   |          |
+   |__________|
+     |   |   |
+     1   2   3
+    GND  DQ VCC (3V3)
+     |   |   |______________ to VCC (3.3V on the NUCLEO-F401RE)  
+     |   |  _|_
+     |   |  | |
+     |   |  | | 4K7
+     |   |  | |
+     |   |  -|-
+     |   |___|______________ to A1 (on the NUCLEO-F401RE) 
+     |
+     |
+     |______________________ to GND (on the NUCLEO-F401RE)   
+
+This SW is just for only one DS18B20
+This SW is a derivative of:: https://developer.mbed.org/users/Sissors/code/DS1820_HelloWorld/
+On the: https://developer.mbed.org/users/Sissors/code/DS1820_HelloWorld/ there is a multi sensor (DS18B20) example.
+
+ Thermistor of 10K - For calculate the temperature we use the Steinhart-Hart equation, see here:
+                     http://www.emcu.it/RaspBerryPi/RaspBerryPi_UK.html#Misura_NTC
+                     
+      
+        ___________________ to VCC (3.3V on the NUCLEO-F401RE)
+       |  
+      _|_
+      | |
+      | | 10K Thermistor (NTC)
+      | |
+      -|-
+       |___________________ to A5 (on the NUCLEO-F401RE)
+      _|_        |
+      | |        |
+      | | 10K   _|_ 
+      | |       ___  0,47uF
+      -|-        |
+       |         |
+       |_________|_________ to GND (on the NUCLEO-F401RE)
+       
+       
+*/
+
+
+
 #define MULTIPLE_PROBES
-#define DATA_PIN        A0
-
+#define DATA_PIN        A1
 
 #ifdef MULTIPLE_PROBES
 
@@ -8,7 +87,15 @@
 #include "DS1820.h"
 
 #define MAX_PROBES      16
- 
+
+float get_temperature(void);
+
+AnalogIn thermistor(A5); // Thermistor
+
+float temp=0;
+float tempArr[100];
+int n=0;
+
 DS1820* probe[MAX_PROBES];
  
 int main() {  
@@ -22,11 +109,23 @@
     }
     
     printf("Found %d device(s)\r\n\n", num_devices);
-    while(1) {
+    while(1) 
+    {
         probe[0]->convertTemperature(true, DS1820::all_devices);         //Start temperature conversion, wait until ready
         for (int i = 0; i<num_devices; i++)
-            printf("Device %d returns %3.1foC\r\n", i, probe[i]->temperature());
-        printf("\r\n");
+            printf("Device %d returns %3.3foC\r\n", i, probe[i]->temperature());
+    
+        for(n=0; n<100; n++)
+        {
+            tempArr[n]=get_temperature();
+            wait_ms(10);
+        }
+        temp=0;
+        for(n=0; n<100; n++)
+            temp=temp + tempArr[n];
+        temp=temp/100;
+        printf("NTC returns      %3.3foC\r\n\n\r", temp);
+        
         wait(1);
     }
     
@@ -41,9 +140,30 @@
 int main() {
     while(1) {
         probe.convertTemperature(true, DS1820::all_devices);         //Start temperature conversion, wait until ready
-        printf("It is %3.1foC\r\n", probe.temperature());
+        printf("It is %3.3foC\r\n", probe.temperature());
         wait(1);
     }
 }
 
-#endif
\ No newline at end of file
+#endif
+
+/*
+ Thermistor (NTC) of 10K - For calculate the temperature we use the Steinhart-Hart equation, see here:
+                     http://www.emcu.it/RaspBerryPi/RaspBerryPi_UK.html#Misura_NTC
+ ATTENTION: Thermistor response, not fully tested.
+*/
+float get_temperature(void)
+{
+    unsigned int a, beta = 3975;
+    float temperature, resistance;
+    
+    a = thermistor.read_u16();
+    
+    /* Calculate the resistance of the thermistor from analog votage read. */
+    resistance = (float) 10000.0 * ((65536.0 / a) - 1);
+    
+    /* Convert the resistance to temperature using Steinhart's Hart equation */
+    temperature=(1/((log(resistance/10000.0)/beta) + (1.0/298.15)))-273.15; 
+    
+    return temperature;
+}