Temperaturmessung mit DS18B20 und LCD Keypad Shiel

Hallo Forum,

ich habe mir das LCD Keypad Shield bestellt und versuche nun die gemessene Temperatur über das Display auszugeben. Lieder bekomme ich immer nur den Wert +85° abgezeigt.

Kann mir jemand eine Tip geben was da falsch laufen kann?

Ich benutze den Beispielcode LCD4Bit_mod

//example use of LCD4Bit_mod library

#include <LCD4Bit_mod.h>
#include <stdio.h>

#define TEMP_PIN 3
//create object to control an LCD.
//number of lines in display=1
LCD4Bit_mod lcd = LCD4Bit_mod(2);

void getCurrentTemp(char *temp);

//Key message
int adc_key_val[5] ={30, 150, 360, 535, 760 };
int NUM_KEYS = 5;
int adc_key_in;
int key=-1;
int oldkey=-1;

void setup() {
  pinMode(13, OUTPUT); //we'll use the debug LED to output a heartbeat

   // initialize DS18B20 datapin
   digitalWrite(TEMP_PIN, LOW);
   pinMode(TEMP_PIN, INPUT); // sets the digital pin as input (logic 1)
  lcd.init();
  //optionally, now set up our application-specific display settings, overriding whatever the lcd did in lcd.init()
  //lcd.commandWrite(0x0F);//cursor on, display on, blink on. (nasty!)
   lcd.clear();
  lcd.printIn("Temperature is");

}

void loop() {

  char temp_string[10];
  adc_key_in = analogRead(0); // read the value from the sensor
  key = get_key(adc_key_in); // convert into key press

if (key != oldkey) // if keypress is detected
{
   delay(50); // wait for debounce time
   adc_key_in = analogRead(0); // read the value from the sensor
   key = get_key(adc_key_in); // convert into key press
   if (key != oldkey)
   {
   oldkey = key;
   getCurrentTemp(temp_string);
   lcd.cursorTo(2, 0); //line=2, x=0
   lcd.printIn(temp_string);
   }
}



}

// Convert ADC value to key number
int get_key(unsigned int input)
{
   int k;

   for (k = 0; k < NUM_KEYS; k++)
   {
   if (input < adc_key_val[k])
   {

   return k;
   }
   }

   if (k >= NUM_KEYS)
   k = -1; // No valid key pressed

   return k;
}

void OneWireReset(int Pin) // reset. Should improve to act as a presence pulse
{
   digitalWrite(Pin, LOW);
   pinMode(Pin, OUTPUT); // bring low for 500 us
   delayMicroseconds(500);
   pinMode(Pin, INPUT);
   delayMicroseconds(500);
}

void OneWireOutByte(int Pin, byte d) // output byte d (least sig bit first).
{
   byte n;

   for(n=8; n!=0; n--)
   {
   if ((d & 0x01) == 1) // test least sig bit
   {
   digitalWrite(Pin, LOW);
   pinMode(Pin, OUTPUT);
   delayMicroseconds(5);
   pinMode(Pin, INPUT);
   delayMicroseconds(60);
   }
   else
   {
   digitalWrite(Pin, LOW);
   pinMode(Pin, OUTPUT);
   delayMicroseconds(60);
   pinMode(Pin, INPUT);
   }

   d=d>>1; // now the next bit is in the least sig bit position.
   }

}

byte OneWireInByte(int Pin) // read byte, least sig byte first
{
   byte d, n, b;

   for (n=0; n<8; n++)
   {
   digitalWrite(Pin, LOW);
   pinMode(Pin, OUTPUT);
   delayMicroseconds(5);
   pinMode(Pin, INPUT);
   delayMicroseconds(5);
   b = digitalRead(Pin);
   delayMicroseconds(50);
   d = (d >> 1) | (b<<7); // shift d to right and insert b in most sig bit position
   }
   return(d);
}

void getCurrentTemp(char *temp)
{
  int HighByte, LowByte, TReading, Tc_100, sign, whole, fract;

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc);
  OneWireOutByte(TEMP_PIN, 0x44); // perform temperature conversion, strong pullup for one sec

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc);
  OneWireOutByte(TEMP_PIN, 0xbe);

  LowByte = OneWireInByte(TEMP_PIN);
  HighByte = OneWireInByte(TEMP_PIN);
  TReading = (HighByte <<

+ LowByte;
  sign = TReading & 0x8000; // test most sig bit
  if (sign) // negative
  {
   TReading = (TReading ^ 0xffff) + 1; // 2's comp
  }
  Tc_100 = (6 * TReading) + TReading / 4; // multiply by (100 * 0.0625) or 6.25

  whole = Tc_100 / 100; // separate off the whole and fractional portions
  fract = Tc_100 % 100;

/*
   if(sign) temp[0]='-';
   else    temp[0]='+';

   temp[1]= whole%100+'0';
   temp[2]= (whole-100*temp[1])%10 +'0' ;
   temp[3]= whole-100*temp[1]-10*temp[2] +'0';

   temp[4]='.';
   temp[5]=fract%10 +'0';
   temp[6]=fract-temp[5]*10 +'0';

   temp[7] = '\0';
*/

   sprintf(temp, "%c%3d%c%2d", (sign==0)?'+':'-', whole, '.', fract);

}

Regards Kirk

	Author	Topic: Temperaturmessung mit DS18B20 und LCD Keypad Shiel (Read 437 times)
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