18B20 Temperature Sensor

Introduction

The DS18B20 arduino Temperature Sensor is a very small thermometer which can be easily hooked into the Arduino MCU through any digital input! It requires very little in the way of additional support, a couple of resistors and some hookup cables and you're set to go.

For more information on the DS18B20 check out Maxim-IC.

The Library

This library is derived from some good work by the Arduino community. This library is, for the most part, purely a refactor version of the existing library. I found the original to be somewhat of a pain to implement and, like most Arduino libraries, code-seperation sucks.

The intention of this Library is to build on Jim Studt work and make it quick and easy for beginners to get started.

Limitations

Benefits

Specification

Temperature Sensor pin definition :

1: Input

2: Power

3: GND

digital input module

Connection Diagram

Digital module connection diagram

Sample Code


#include <OneWire.h>

int DS18S20_Pin = 2; //DS18S20 Signal pin on digital 2

//Temperature chip i/o
OneWire ds(DS18S20_Pin);  // on digital pin 2

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

void loop(void) {
  float temperature = getTemp();
  Serial.println(temperature);

  delay(100); //just here to slow down the output so it is easier to read

}


float getTemp(){
  //returns the temperature from one DS18S20 in DEG Celsius

  byte data[12];
  byte addr[8];

  if ( !ds.search(addr)) {
      //no more sensors on chain, reset search
      ds.reset_search();
      return -1000;
  }

  if ( OneWire::crc8( addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return -1000;
  }

  if ( addr[0] != 0x10 && addr[0] != 0x28) {
      Serial.print("Device is not recognized");
      return -1000;
  }

  ds.reset();
  ds.select(addr);
  ds.write(0x44,1); // start conversion, with parasite power on at the end

  byte present = ds.reset();
  ds.select(addr);
  ds.write(0xBE); // Read Scratchpad


  for (int i = 0; i < 9; i  ) { // we need 9 bytes
    data[i] = ds.read();
  }

  ds.reset_search();

  byte MSB = data[1];
  byte LSB = data[0];

  float tempRead = ((MSB << 8) | LSB); //using two's compliment
  float TemperatureSum = tempRead / 16;

  return TemperatureSum;

}

More Documents

DFshopping_car1.png Get DS18B20 arduino Temperature Sensor from DFRobot Store or DFRobot Distributor.

Category: Home > Modules&Sensors >Sensors > Temperature Sensors

category: Product_Manual category: DFR_Series category: Sensors category: Source category: Diagram

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