The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. In addition, the DS18B20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply. Datasheet.
Wiring
Below are two different wirings, with a breakout board including the pull-up resistor, and with the pull up resistor added. The sketch is the same for both wiring alternatives.
KY-001
The KY-001 Arduino Temperature Module has a built-in pull-up resistor and you can wire it directly to the 5 volt power supply as shown below.
Wiring of the KY-001 Arduino module with the DS18B20 temperature sensor.
Waterproof and cabled
If your module lacks the pull-up resistor you must put a 4.7 kOhm resistore between the %v poser and the data cable, as shown in the sketch below.
Wiring of the waterproof and encased DS18B20 temperature sensor, the wiring must include the pull-up resistor of 4.7 kOhm.
Sketch
The sketch includes two libraries: OneWire.h and DallasTemperature.h. You need to install both to your library as explained in the official Arduino page on Installing Additional Arduino Libraries. In this version I have put the analog sensor signal on port A1.
/********************************************************************/
// First we include the libraries
#include <OneWire.h>
#include <DallasTemperature.h>
/********************************************************************/
// Data wire is plugged into pin 1 on the Arduino
#define ONE_WIRE_BUS 1
/********************************************************************/
// Setup a oneWire instance to communicate with any OneWire devices
// (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);
/********************************************************************/
// Pass our oneWire reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);
/********************************************************************/
void setup(void)
{
// start serial port
Serial.begin(9600);
Serial.println("Dallas Temp. IC Control Library Demo");
// Start up the library
sensors.begin();
}
void loop(void)
{
// call sensors.requestTemperatures() to issue a global temperature
// request to all devices on the bus
/********************************************************************/
Serial.print(" Requesting temp...");
sensors.requestTemperatures(); // Send the command to get temperature readings
Serial.println("DONE");
/********************************************************************/
Serial.print("Temp (C) is: ");
Serial.print(sensors.getTempCByIndex(0)); // Why "byIndex"?
// You can have more than one DS18B20 on the same bus.
// 0 refers to the first IC on the wire
delay(1000);
}
