Arduino Uno DS18B20: Industrial Submersible Thermometer

Professional Maxim DS18B20 digital temperature sensor features three-layer 3-element matched thermal system (laser-trimmed bandgap reference + proportional-to-absolute-temperature sensor + delta-sigma ADC) delivering -55 to +125°C range with ±0.5°C accuracy (-10 to +85°C) and 0.5°C resolution in stainless steel TO-92 package (6mm OD x 55mm L).

OneWire 3-wire interface (GND/VCC/DQ pin 2) supports 115200bps Manchester-encoded packets with unique 64-bit ROM ID, parasitic power option, and programmable 9-12 bit conversion times (93.75ms-750ms). 4.7kΩ pull-up enables 20+ sensor multi-drop bus over 50m+ cable.

Production Thermometric Components

Arduino UNO R3 digital GPIO (pin 2)
DS18B20 waterproof probe (3m cable, SS304 sheath)
4.7kΩ pull-up resistor (mandatory)
Male-to-male jumper wires (3 pieces)
OneWire + DallasTemperature libraries
12V cooling relay + 10kΩ setpoint pot

Industrial OneWire Thermometry Interface

RED (VCC): Arduino 5V (3.0-5.5V range)

BLACK (GND): Arduino GND

YELLOW (DQ): Arduino Digital Pin 2 + 4.7kΩ to 5V

Program: Arduino Uno DS18B20 - Process Cooling Controller

/*
  DS18B20 Waterproof Professional Thermostat
  Libraries: OneWire + DallasTemperature (Miles Burton)
*/
#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
const int compressorPin = 7;
const int heaterPin = 8;
const float SETPOINT = 20.0;  // Process 20°C
const float HYSTERESIS = 0.5; // ±0.5°C band

void setup() {
  Serial.begin(9600);
  pinMode(compressorPin, OUTPUT);
  pinMode(heaterPin, OUTPUT);
  sensors.begin();
  sensors.setResolution(12);  // 0.0625°C
  
  Serial.println("=== DS18B20 Process Thermostat Active ===");
  Serial.println("T°C | Status | Action | Resolution");
  Serial.println("---------------------------------------");
}

void loop() {
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0);
  
  if(tempC == DEVICE_DISCONNECTED_C) {
    Serial.println("ERROR: DS18B20 disconnected!");
    return;
  }
  
  // Process control with hysteresis
  Serial.print("Temp: ");
  Serial.print(tempC, 2);
  Serial.print("°C | ");
  
  if(tempC > SETPOINT + HYSTERESIS) {
    digitalWrite(compressorPin, HIGH);
    digitalWrite(heaterPin, LOW);
    Serial.println("COOLING");
  } else if(tempC < SETPOINT - HYSTERESIS) {
    digitalWrite(compressorPin, LOW);
    digitalWrite(heaterPin, HIGH);
    Serial.println("HEATING");
  } else {
    digitalWrite(compressorPin, LOW);
    digitalWrite(heaterPin, LOW);
    Serial.println("HOLD");
  }
  
  Serial.print("Res: ");
  Serial.println(sensors.getResolution(0));
  
  delay(1000);
}

OneWire Library Production Deployment

Library Manager → OneWire + DallasTemperature. 4.7kΩ pull-up mandatory. 12-bit resolution = 0.0625°C. Serial Monitor displays precise process control.

Advanced Multi-Probe & Bus Configuration

Program: Arduino Uno DS18B20 - 4-Zone Temperature Array

// Multi-drop OneWire bus (20+ sensors)
void printAddresses() {
  uint8_t address[8];
  while(oneWire.search(address)) {
    Serial.print("ROM: ");
    for(int i=0; i<8; i++) {
      Serial.print(address[i], HEX);
      Serial.print(" ");
    }
    Serial.println();
  }
  oneWire.reset_search();
}

void loop() {
  sensors.requestTemperatures();
  for(int i=0; i<sensors.getDeviceCount(); i++) {
    float temp = sensors.getTempCByIndex(i);
    Serial.print("Probe ");
    Serial.print(i);
    Serial.print(": ");
    Serial.println(temp, 2);
  }
}

DS18B20 Stainless Probe Specifications

Range: -55 to +125°C
Accuracy: ±0.5°C (-10 to +85°C)
Resolution: 9-12 bits (0.5 to 0.0625°C)
Conversion: 93.75ms (12-bit)
Probe: SS304 6x55mm, 3m+ cable, IP68

Industrial Process Applications

Liquid immersion temperature (brew kettles, chillers)

HVAC refrigerant line monitoring

Soil temperature profiling

Program: Arduino Uno DS18B20 - Fermentation Controller

// Beer fermentation profile
const float PRIMARY = 18.0;  // 18°C primary
const float SECONDARY = 20.0; // 20°C secondary
unsigned long fermentStart = 0;

void loop() {
  float temp = sensors.getTempCByIndex(0);
  unsigned long days = (millis() - fermentStart) / 86400000UL;
  
  float setpoint = (days < 7) ? PRIMARY : SECONDARY;
  if(temp > setpoint + 0.3) digitalWrite(7, HIGH);  // Peltier cooling
  else digitalWrite(7, LOW);
}

OneWire 3-Wire Protocol Timing

Reset: 480μs LOW → 70μs wait
Presence: 60-240μs LOW (slave response)
Read slot: 1μs → sample → 15μs release
Write 0: 60μs LOW → 10μs release
Write 1: 1μs LOW → 60μs release

Multi-Drop Bus & Parasitic Power

Program: Arduino Uno DS18B20 - Search & Alarm System

// Temperature excursion alarm
void loop() {
  sensors.requestTemperatures();
  float temp = sensors.getTempCByIndex(0);
  
  if(temp > 65.0 || temp < -20.0) {
    tone(9, 2000, 500);
    Serial.println("*** TEMPERATURE ALARM! ***");
  }
  
  Serial.printf("T: %6.2f°C | Status: %s\n", 
    temp, (temp > 65 || temp < -20) ? "ALARM" : "OK");
}

Production Deployment Specifications

4.7kΩ pull-up resistor (mandatory)
3-core shielded cable (>10m runs)
12-bit resolution (750ms conversion)
20+ sensors per bus (500m total)
IP68 stainless probe (full immersion)
-55 to +125°C full range

Calibration & Maintenance Protocol

Ice point 0.0°C verification, boiling 100.0°C calibration (pressure corrected). Monthly 2-point check. Cable strain relief mandatory. Avoid kinks in SS sheath. 0.1°C precision maintained 5+ years.