Arduino Project 1a: Temperature Sensor

Introduction

In this project we are going to create a digital thermometer to monitor the temperature of the aquarium. We will use this simple circuit in future projects for controlling equipment such as chillers, heaters and fans automatically.

Parts

• Arduino Uno or compatible
• DS18B20 Temperature Sensor Probe Waterproof w/Pluggable Terminal Adapter
• 16 x 2 LCD w/ I2C
• Jumper wires

Schematics

Assemble all parts per schematic

Note: If Pluggable Terminal Adapter is not used then a 4.70K ohm resister is needed,

Code

Library’s required

• OneWire.h
• DallasTemperature.h
• LiquidCrystal.h

Notes

• Change Sensor pin number if needed
• Change LCD I2C address if needed

Sketch

/*
 * Arduino Project 1a
 * Complete Project details https://thediyaquarium.com/
 */

#include <OneWire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal_I2C.h>

const int SENSOR_PIN = 7; // Arduino pin connected to DS18B20 sensor's DQ pin

OneWire oneWire(SENSOR_PIN);         // setup a oneWire instance
DallasTemperature sensors(&oneWire); // pass oneWire to DallasTemperature library
LiquidCrystal_I2C lcd(0x27, 16, 2);  // I2C address 0x27, 16 column and 2 rows


float tempCelsius;    // temperature in Celsius
float tempFahrenheit; // temperature in Fahrenheit

void setup() 
{
  sensors.begin();    // initialize the sensor
  lcd.init();         // initialize the lcd
  lcd.backlight();    // open the backlightSerial
}

void loop() 
{
 sensors.requestTemperatures();             // send the command to get temperatures
 tempCelsius = sensors.getTempCByIndex(0);  // read temperature in Celsius
 tempFahrenheit = tempCelsius * 9 / 5 + 32; // convert Celsius to Fahrenheit

  lcd.clear();
  lcd.setCursor(0, 0);       // start to print at the first row
  lcd.print("  Temperature");    // print Temperature
  lcd.setCursor(0, 1);       // start to print at the second row
  lcd.print(tempFahrenheit); // print the temperature in Fahrenheit
  lcd.print((char)223);      // print ° character
  lcd.print("F  ");
  lcd.print(tempCelsius); // print the temperature in Celsius
  lcd.print((char)223);      // print ° character
  lcd.print("C");
  delay(500);
}

Operation

Load code (Sketch), put end of probe in aquarium

As long as there is power to the board, Temperature will be displayed on LCD and updated every 500ms

Summary

Can be expanded to monitor temperature across multiple aquariums

Can be expanded to record data and send to computer or cell phone

Can be updated to send warning to cell phone if readings drop below or exceeds specific temperature