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Topic: ds18x20 temprature data question (Read 682 times) previous topic - next topic

flintec

May 09, 2012, 09:38 am Last Edit: May 09, 2012, 10:05 am by Coding Badly Reason: 1
hello im using a ds1825 but its weary similar to the ds1820 so it works with this one as well
the thing is i get this readings!
ROM = 3B F7 5A 2 0 0 0 7A
 Chip = DS1822
 Data = 1 7A 1 4B 46 72 FF 6 10 96  CRC=96
 Temperature = 23.62 Celsius, 74.52 Fahrenheit
wich seems to be corrent no problem so far but the only thing im intrested in is
Data = 1 7A 1 4B 46 (72) FF 6 10 96  CRC=96 yes the number 72 in the data reading
can someone help me change in the program to just write that number instead of the rest of the crap?
ant still display the temprature and ROM?
Code: [Select]
#include <OneWire.h>

// OneWire DS18S20, DS18B20, DS1822 Temperature Example
//
// http://www.pjrc.com/teensy/td_libs_OneWire.html
//
// The DallasTemperature library can do all this work for you!
// http://milesburton.com/Dallas_Temperature_Control_Library

OneWire  ds(10);  // on pin 10

void setup(void) {
 Serial.begin(9600);
}

void loop(void) {
 byte i;
 byte present = 0;
 byte type_s;
 byte data[12];
 byte addr[8];
 float celsius, fahrenheit;
 
 if ( !ds.search(addr)) {
   Serial.println("No more addresses.");
   Serial.println();
   ds.reset_search();
   delay(250);
   return;
 }
 
 Serial.print("ROM =");
 for( i = 0; i < 8; i++) {
   Serial.write(' ');
   Serial.print(addr[i], HEX);
 }

 if (OneWire::crc8(addr, 7) != addr[7]) {
     Serial.println("CRC is not valid!");
     return;
 }
 Serial.println();

 // the first ROM byte indicates which chip
 switch (addr[0]) {
   case 0x10:
     Serial.println("  Chip = DS18S20");  // or old DS1820
     type_s = 1;
     break;
   case 0x28:
     Serial.println("  Chip = DS18B20");
     type_s = 0;
     break;
   case 0x3b:
     Serial.println("  Chip = DS1822");
     type_s = 0;
     break;
   default:
     Serial.println("Device is not a DS18x20 family device.");
     return;
 }

 ds.reset();
 ds.select(addr);
 ds.write(0x44,1);         // start conversion, with parasite power on at the end
 
 delay(1000);     // maybe 750ms is enough, maybe not
 // we might do a ds.depower() here, but the reset will take care of it.
 
 present = ds.reset();
 ds.select(addr);    
 ds.write(0xBE);         // Read Scratchpad

 Serial.print("  Data = ");
 Serial.print(present,HEX);
 Serial.print(" ");
 for ( i = 0; i < 9; i++) {           // we need 9 bytes
   data[i] = ds.read();
   Serial.print(data[i], HEX);
   Serial.print(" ");
 }
 Serial.print(" CRC=");
 Serial.print(OneWire::crc8(data, 8), HEX);
 Serial.println();

 // convert the data to actual temperature

 unsigned int raw = (data[1] << 8) | data[0];
 if (type_s) {
   raw = raw << 3; // 9 bit resolution default
   if (data[7] == 0x10) {
     // count remain gives full 12 bit resolution
     raw = (raw & 0xFFF0) + 12 - data[6];
   }
 } else {
   byte cfg = (data[4] & 0x60);
   if (cfg == 0x00) raw = raw << 3;  // 9 bit resolution, 93.75 ms
   else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms
   else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms
   // default is 12 bit resolution, 750 ms conversion time
 }
 celsius = (float)raw / 16.0;
 fahrenheit = celsius * 1.8 + 32.0;
 Serial.print("  Temperature = ");
 Serial.print(celsius);
 Serial.print(" Celsius, ");
 Serial.print(fahrenheit);
 Serial.println(" Fahrenheit");
}



Moderator edit: [code] [/code] tags added.

pylon

This should do what you want if I understood your intention correctly.

Code: [Select]
#include <OneWire.h>

// OneWire DS18S20, DS18B20, DS1822 Temperature Example
//
// http://www.pjrc.com/teensy/td_libs_OneWire.html
//
// The DallasTemperature library can do all this work for you!
// http://milesburton.com/Dallas_Temperature_Control_Library

OneWire  ds(10);  // on pin 10

void setup(void) {
  Serial.begin(9600);
}

void loop(void) {
  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];
  float celsius, fahrenheit;
 
  if ( !ds.search(addr)) {
    Serial.println("No more addresses.");
    Serial.println();
    ds.reset_search();
    delay(250);
    return;
  }
 
  Serial.print("ROM =");
  for( i = 0; i < 8; i++) {
    Serial.write(' ');
    Serial.print(addr[i], HEX);
  }

  if (OneWire::crc8(addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return;
  }
  Serial.println();

/*
  // the first ROM byte indicates which chip
  switch (addr[0]) {
    case 0x10:
      Serial.println("  Chip = DS18S20");  // or old DS1820
      type_s = 1;
      break;
    case 0x28:
      Serial.println("  Chip = DS18B20");
      type_s = 0;
      break;
    case 0x3b:
      Serial.println("  Chip = DS1822");
      type_s = 0;
      break;
    default:
      Serial.println("Device is not a DS18x20 family device.");
      return;
  }
*/
  ds.reset();
  ds.select(addr);
  ds.write(0x44,1);         // start conversion, with parasite power on at the end
 
  delay(1000);     // maybe 750ms is enough, maybe not
  // we might do a ds.depower() here, but the reset will take care of it.
 
  present = ds.reset();
  ds.select(addr);   
  ds.write(0xBE);         // Read Scratchpad

  Serial.print("  Data = ");
  Serial.println(data[4]);
/*
  Serial.print(present,HEX);
  Serial.print(" ");
  for ( i = 0; i < 9; i++) {           // we need 9 bytes
    data[i] = ds.read();
    Serial.print(data[i], HEX);
    Serial.print(" ");
  }
  Serial.print(" CRC=");
  Serial.print(OneWire::crc8(data, 8), HEX);
  Serial.println();
*/

  // convert the data to actual temperature

  unsigned int raw = (data[1] << 8) | data[0];
  if (type_s) {
    raw = raw << 3; // 9 bit resolution default
    if (data[7] == 0x10) {
      // count remain gives full 12 bit resolution
      raw = (raw & 0xFFF0) + 12 - data[6];
    }
  } else {
    byte cfg = (data[4] & 0x60);
    if (cfg == 0x00) raw = raw << 3;  // 9 bit resolution, 93.75 ms
    else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms
    else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms
    // default is 12 bit resolution, 750 ms conversion time
  }
  celsius = (float)raw / 16.0;
  fahrenheit = celsius * 1.8 + 32.0;
  Serial.print("  Temperature = ");
  Serial.print(celsius);
  Serial.print(" Celsius, ");
  Serial.print(fahrenheit);
  Serial.println(" Fahrenheit");
}

flintec

figured it out myself after a while but thank you anyway :)

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