Dallas' DS1820 family temperature sensor. For more details see [https://developer.mbed.org/users/hudakz/code/DS1820/wiki/Homepage]

Dependencies:   OneWire

Dependents:   BLE_nRF24L01 frdm_serialfgmp gather_sensor_data UltiSaverController ... more

Some programs using the DS1820 library:

Import programDS1820_Hello

Simple DS1820 sensor demo showing how to use the DS1820 library [https://developer.mbed.org/users/hudakz/code/DS1820/]

Import programBLE_nRF24L01

Bluetooth Low Energy (BLE) beacon with nRF24L01(+). Data is received and displayed by Android device (Android app source code is attached).

Examples of use:

Single DS1820 sensor

/*
 * Single DS1820 sensor GPIO driven
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the DS1820's data pin and the +3.3V pin
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
 
#include "mbed.h"
#include "DS1820.h"
 
Serial serial(USBTX, USBRX);
 
int main() {
    DS1820  ds1820(D8);    // substitute D8 with actual mbed pin name connected to the DS1820 data pin    
                             
    if(ds1820.begin()) {
        while(1) {
            ds1820.startConversion();     // start temperature conversion
            ThisThread::sleep_for(1000);  // let DS1820 complete the temperature conversion
            serial.printf("temp = %3.1f\r\n", ds1820.read());     // read temperature
        }
    } else
        serial.printf("No DS1820 sensor found!\r\n");
}
 

Single DS1820 sensor. Data integrity is assured by performing CRC.

/*
 * Single DS1820 sensor GPIO driven + performing CRC
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the DS1820's data pin and the +3.3V pin
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
 
#include "mbed.h"
#include "DS1820.h"
 
Serial serial(USBTX, USBRX);
 
int main() {
    DS1820  ds1820(D8);    // substitute D8 with actual mbed pin name connected to the DS1820 data pin   
    float   temp = 0;
    int     error = 0; 
                             
    if(ds1820.begin()) {
        while(1) {
            ds1820.startConversion();    // start temperature conversion
            ThisThread::sleep_for(1000); // let DS1820 complete the temperature conversion
            error = ds1820.read(temp);   // read temperature from DS1820 and perform cyclic redundancy check (CRC)
            switch(error) {
            case 0:    // no errors -> 'temp' contains the value of measured temperature
                serial.printf("temp = %3.1f\r\n", temp);
                break;
            case 1:    // no sensor present -> 'temp' is not updated
                serial.printf("no sensor present\n\r");
                break;
            case 2:    // CRC error -> 'temp' is not updated
                serial.printf("CRC error\r\n");
            } 
        }
    } else
        serial.printf("No DS1820 sensor found!\r\n");
}
 

Several DS1820 sensors connected to the same 1-wire bus.

/*
 * Multiple sensors GPIO driven
 *
 * Note: Don't forget to connect a 4.7k Ohm resistor 
 *       between the 1-wire bus data line and the +3.3V rail
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |                |                    |
 *          |           GPIO |--------------------o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */

#include "mbed.h"
#include "DS1820.h"

#define     MAX_SENSOSRS   32   // max number of DS1820 sensors to be connected to the 1-wire bus (max 256)

DS1820*     ds1820[MAX_SENSOSRS];
Serial      pc(USBTX, USBRX);
DigitalOut  led(LED1);
OneWire     oneWire(D8);        // substitute D8 with the actual pin name connected to the 1-wire bus
int         sensorsFound = 0;   // counts the actually found DS1820 sensors

int main()
{
    pc.printf("\r\n--Starting--\r\n");
    
    //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
    for (sensorsFound = 0; sensorsFound < MAX_SENSOSRS; sensorsFound++) {
        ds1820[sensorsFound] = new DS1820(&oneWire);
        if (!ds1820[sensorsFound]->begin()) {
            delete ds1820[sensorsFound];
            break;
        }
    }

    switch (sensorsFound) {
        case 0:
            pc.printf("No DS1820 sensor found!\r\n");
            return -1;

        case 1:
            pc.printf("One DS1820 sensor found.\r\n");
            break;

        default:
            pc.printf("Found %d DS1820 sensors.\r\n", sensorsFound);
    }

    while (1) {
        pc.printf("----------------\r\n");
        for (int i = 0; i < sensorsFound; i++)
            ds1820[i]->startConversion();        // start temperature conversion from analog to digital
        ThisThread::sleep_for(1000);             // let DS1820 sensors complete the temperature conversion
        for (int i = 0; i < sensorsFound; i++) {
            if (ds1820[i]->isPresent())
                pc.printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176); // read temperature
        }
    }
}


Several DS1820 sensors connected to the same 1-wire bus. UART is used to implement the bus

/*
 * Multiple sensors UART driven:
 * 
 *          UART is driving the 1-Wire Bus Master according to Maxim Integrated application note
 *
 *          https://www.maximintegrated.com/en/design/technical-documents/tutorials/2/214.html
 *
 *          In addition to the 4.7k Ohm resistor between the 1-wire data bus/line and the +3.3V pin,
 *          a 470 Ohm resistor shall be tied to the UART's tx and rx pin. UART's rx pin is then used
 *          as 1-wire data bus/line.
 *
 *           ----------------
 *          |                |   ----------------------->  +3.3V
 *          |   MBED BOARD   |  |
 *          |                |  |   ------
 *          |          +3.3V |--o--| 4.7k |-------
 *          |                |      ------        |
 *          |                |      ------        |
 *          |        UART TX |-----|  470 |---    |
 *          |                |      ------    |   |
 *          |                |                |   |
 *          |        UART RX |----------------o---o----->  1-wire bus/line
 *          |                |
 *          |                |
 *          |            GND |-------------------------->  GND
 *          |                |
 *           ----------------
 *
 */
#include "mbed.h"
#include "DS1820.h"

#define MAX_SENSOSRS    32      // max number of DS1820 sensors to be connected to the 1-wire bus (max 256)
DS1820*     ds1820[MAX_SENSOSRS];
DigitalOut  led(LED1);
OneWire     oneWire(p9, p10);       // LPC1768 (UART Tx pin, UART Rx pin)
//OneWire     oneWire(PA_0, PA_1);    // NUCLE0-F446RE (UART Tx pin, UART Rx pin)
int         sensorsFound = 0;       // counts the actually found DS1820 sensors

/**
 * @brief
 * @note
 * @param
 * @retval
 */
int main()
{
    printf("\r\n--Starting--\r\n");

    //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
    for (sensorsFound = 0; sensorsFound < MAX_SENSOSRS; sensorsFound++) {
        ds1820[sensorsFound] = new DS1820(&oneWire);
        if (!ds1820[sensorsFound]->begin()) {
            delete ds1820[sensorsFound];
            break;
        }
    }

    switch (sensorsFound) {
        case 0:
            printf("No DS1820 sensor found!\r\n");
            return -1;

        case 1:
            printf("One DS1820 sensor found.\r\n");
            break;

        default:
            printf("Found %d DS1820 sensors.\r\n", sensorsFound);
    }

    while (1) {
        led = !led;

        printf("----------------\r\n");
        for (int i = 0; i < sensorsFound; i++)
            ds1820[i]->startConversion();   // start temperature conversion from analog to digital
        #if (MBED_MAJOR_VERSION > 5)
            ThisThread::sleep_for(1s);
        #else
            wait(1);
        #endif


        for (int i = 0; i < sensorsFound; i++) {
            if (ds1820[i]->isPresent())
                printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176);   // read temperature
        }
    }
}
Revision:
24:d683d826dccd
Parent:
23:74a4ff420541
--- a/DS1820.h	Mon Jul 20 08:09:58 2020 +0000
+++ b/DS1820.h	Mon Dec 28 21:15:27 2020 +0000
@@ -1,7 +1,7 @@
 #ifndef DS1820_H_
     #define DS1820_H_
 
-    #include <OneWire.h>
+    #include "OneWire.h"
 
 /**
  * Dallas' DS1820 family temperature sensor.
@@ -9,20 +9,20 @@
  * available at <http://developer.mbed.org/users/hudakz/code/OneWire/>
  *
  * Example of use:
- * 
+ *
  * @code
- * 
+ *
  * Single sensor.
  *
  * #include "mbed.h"
  * #include "DS1820.h"
- * 
+ *
  * Serial      pc(USBTX, USBRX);
  * DigitalOut  led(LED1);
  * DS1820      ds1820(D8);  // substitute D8 with actual mbed pin name connected to 1-wire bus
  * float       temp = 0;
  * int         result = 0;
- * 
+ *
  * int main()
  * {
  *     pc.printf("\r\n--Starting--\r\n");
@@ -35,30 +35,30 @@
  *                 case 0:                 // no errors -> 'temp' contains the value of measured temperature
  *                     pc.printf("temp = %3.1f%cC\r\n", temp, 176);
  *                     break;
- * 
+ *
  *                 case 1:                 // no sensor present -> 'temp' is not updated
  *                     pc.printf("no sensor present\n\r");
  *                     break;
- * 
+ *
  *                 case 2:                 // CRC error -> 'temp' is not updated
  *                     pc.printf("CRC error\r\n");
  *             }
- * 
+ *
  *             led = !led;
  *         }
  *     }
  *     else
  *         pc.printf("No DS1820 sensor found!\r\n");
  * }
- * 
- * 
+ *
+ *
  * More sensors connected to the same 1-wire bus.
- * 
+ *
  * #include "mbed.h"
  * #include "DS1820.h"
- * 
+ *
  * #define     SENSORS_COUNT   64      // number of DS1820 sensors to be connected to the 1-wire bus (max 256)
- * 
+ *
  * Serial      pc(USBTX, USBRX);
  * DigitalOut  led(LED1);
  * OneWire     oneWire(D8);            // substitute D8 with actual mbed pin name connected to the DS1820 data pin
@@ -66,10 +66,10 @@
  * int         sensors_found = 0;      // counts the actually found DS1820 sensors
  * float       temp = 0;
  * int         result = 0;
- * 
+ *
  * int main() {
  *     int i = 0;
- *     
+ *
  *     pc.printf("\r\n Starting \r\n");
  *     //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus
  *     for(i = 0; i < SENSORS_COUNT; i++) {
@@ -79,20 +79,20 @@
  *             break;
  *         }
  *     }
- *     
+ *
  *     sensors_found = i;
- *     
+ *
  *     if (sensors_found == 0) {
  *         pc.printf("No DS1820 sensor found!\r\n");
  *         return -1;
  *     }
  *     else
  *         pc.printf("Found %d sensors.\r\n", sensors_found);
- *     
+ *
  *     while(1) {
  *         pc.printf("-------------------\r\n");
  *         for(i = 0; i < sensors_found; i++)
- *             ds1820[i]->startConversion();   // start temperature conversion from analog to digital       
+ *             ds1820[i]->startConversion();   // start temperature conversion from analog to digital
  *         wait(1.0);                          // let DS1820s complete the temperature conversion
  *         for(int i = 0; i < sensors_found; i++) {
  *             if(ds1820[i]->isPresent())
@@ -100,32 +100,34 @@
  *         }
  *     }
  * }
- * 
+ *
  * @endcode
- * 
- * Note: Don't forget to connect a 4.7k Ohm resistor 
+ *
+ * Note: Don't forget to connect a 4.7k Ohm resistor
  *       between the DS1820's data pin and the +3.3V pin
  *
  */
 class   DS1820
 {
-    OneWire *oneWire;
-    bool    present;    
-    bool    model_s;
-    uint8_t data[12];
-    uint8_t addr[8];
+    OneWire*        _oneWire;
+    bool            _present;
+    bool            _model_s;
+    uint8_t         _data[12];
+    uint8_t         _addr[8];
+    static uint8_t  _lastAddr[8];
+
     float   toFloat(uint16_t word);
-    static  uint8_t lastAddr[8];
-    
+
 public:
-    DS1820(PinName pin, int sample_point_us = 13);
-//    DS1820(char model, PinName pin);
-    DS1820(OneWire* wire);
-    bool   begin(void);
-    bool   isPresent();
-    void   setResolution(uint8_t res);
-    void   startConversion(void);
-    float  read(void);
+    DS1820(PinName gpioPin, int samplePoint_us = 13);
+    DS1820(PinName txPin, PinName rxPin);
+    DS1820(OneWire* oneWire);
+
+    bool    begin(void);
+    bool    isPresent();
+    void    setResolution(uint8_t res);
+    void    startConversion(void);
+    float   read(void);
     uint8_t read(float& temp);
 };
 #endif /* DS1820_H_ */