Mai multi senzori de tip DS18B20 (sau MAX31820) in paralel (2)

   In articolul anterior, Mai multi senzori de tip DS18B20 (sau MAX31820) in paralel, am conectat 3 senzori din familia DS18x20 (unul DS18B20 si 2 de tipul MAX31820), acum ca am primit inca 2 monstre de tipul DS18B20 de la Dallas Semiconductor (Maxim Integrated), cum primisem, in ianuarie, si pe cei 2 senzori MAX31820, am zis ca pot citi temperatura in 5 puncte.

 

   Schema de conectare a senzprilor este identica, toti 5 vor fi in paralel:

iar prezentarea datelor am facut-o pe un afisaj LCD alfanumeric cu 16 coloane si 2 randuri (1602 sau 16x2):

   Montajul arata asa:

   Am adaptat sketch-ul folosit in articolul Mai multi senzori de tip DS18B20 (sau MAX31820) in paralel combinandu-l cu cel din articolul Interfata i2c la LCD pentru Arduino:

// full sketch by niq_ro from http://nicuflorica.blogspot.com
// or http://www.tehnic.go.ro
// or http://arduinotehniq.blogspot.com/

#include <Wire.h> // for i2c protocol

#include <OneWire.h>
// http://www.pjrc.com/teensy/td_libs_OneWire.html
// http://milesburton.com/Dallas_Temperature_Control_Library
OneWire  ds(10);  // on pin 10 (a 4.7K resistor is necessary)  

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x20,16,2); // 0x20 is adresss for LCC 16x2

byte grad[8] = {
  B01110,
  B10001,
  B10001,
  B01110,
  B00000,
  B00000,
  B00000,
};

int ics =0; //count number of sensor

void setup(){
  lcd.init(); 
  lcd.backlight(); //backlight is now ON
  // set up the LCD's number of columns and rows: 
  lcd.createChar(0, grad);
  lcd.begin(16, 2);
  // Print a logo message to the LCD.
  lcd.print("www.tehnic.go.ro");  
  lcd.setCursor(0, 1);
  lcd.print("creat de niq_ro");
  delay (2500);
  lcd.clear();
   
  // Print a message to the LCD.
  lcd.setCursor(1, 0);
  lcd.print("temperatura in");
  lcd.setCursor(1, 1);
  lcd.print("mai multe zone");
  delay (2500);
  lcd.clear();
}



void loop(){
  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];
  float celsius;
  
  
  if ( !ds.search(addr)) {
    lcd.clear();   
    lcd.setCursor(0, 1);
    lcd.print("doar ");
    lcd.print(ics);
    lcd.print(" senzor(i)");    
    ds.reset_search();
    ics=0;
    return;
  }
  
ics++; 

  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

  for ( i = 0; i < 9; i++) {           // we need 9 bytes
    data[i] = ds.read();
  }
  // Convert the data to actual temperature
  // because the result is a 16 bit signed integer, it should
  // be stored to an "int16_t" type, which is always 16 bits
  // even when compiled on a 32 bit processor.
  int16_t 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);
    // at lower res, the low bits are undefined, so let's zero them
    if (cfg == 0x00) raw = raw & ~7;  // 9 bit resolution, 93.75 ms
    else if (cfg == 0x20) raw = raw & ~3; // 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
  }

lcd.clear();
lcd.setCursor(0, 1);
  lcd.print("ROM=");
  for( i = 0; i < 8; i++) {
    lcd.print(' ');
    lcd.print(addr[i], HEX);
  }

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

  celsius = (float)raw / 16.0;

  lcd.setCursor(0,0);
  lcd.print("Temp");
  lcd.print(ics);
  lcd.print(" = ");
  lcd.print(celsius);
  lcd.write(byte(0));
  lcd.print("C   ");
  
  delay(3000);
}

   Am facut si 2 filmulete:
- masurare temperatura in mai multe puncte cu DS18B20 si MAX31820 folosind Arduino si LCD1602 cu i2c

- multipoint thermometer with DS18B20 and MAX31820, Arduino and LCD1602 with i2c interface

11.02.2014
   Am desenat schema completa de conectare a senzorilor din familia DS18x20 (DS18B20, DS18S20, DS1822, MAX31820) si a afisajului LCD 1602 cu interfata i2c: