Digital Temperature Monitoring: ESP32 + DS18B20 Sensor System

15-07-2025

🌡️ What is DS18B20?

The DS18B20 is a digital temperature sensor from Maxim Integrated (now Analog Devices), known for:

✅ Accurate temperature readings
✅ Unique 64-bit serial code (for multiple sensors on one wire)
✅ 1-Wire interface (needs only 1 data line + GND + VCC)
✅ Waterproof versions available

📋 Key Features

Feature	Description
Temperature Range	-55°C to +125°C
Accuracy	±0.5°C (from -10°C to +85°C)
Interface	1-Wire digital
Resolution	Programmable: 9 to 12 bits
Voltage	3.0V to 5.5V
ID Address	Each sensor has a unique ID

🧰 Components Used

Component	Description
ESP32 Dev Board	Microcontroller
DS18B20 Sensor	Waterproof or standard TO-92 version
4.7kΩ Resistor	Pull-up resistor for 1-Wire
Jumper Wires	For connections
Breadboard (opt.)	For prototyping

🔌 DS18B20 Pinout and ESP32 Wiring

DS18B20 Pin	Wire Color (usually)	Connect to ESP32	Description
VCC	Red	3.3V or 5V	Power
GND	Black	GND	Ground
DQ (Data)	Yellow	GPIO 15 (example)	1-Wire Data

🔧 Add a 4.7kΩ resistor between VCC and DQ.

🧩 Step-by-Step in Arduino IDE

📚 Step 1: Install Required Libraries

Open Arduino IDE
Go to Sketch > Include Library > Manage Libraries
Search and install:
- OneWire by Paul Stoffregen
- DallasTemperature by Miles Burton

🎯 Applications of DS18B20

Application	Use Case Example
🏠 Home Automation	Room/ambient temperature
🚰 Water Monitoring	Check water heater/cooler
🌿 Agriculture	Soil/environmental sensing
🔥 Fire Detection	Overheat alert in machines
🐢 Aquarium Monitoring	Check fish tank or pet enclosures

🛠️ Troubleshooting

Problem	Fix
Reading -127.00 °C	Sensor not connected or wrong pin
Output always 0.00 °C	Missing pull-up resistor
Sensor not detected	Use `.getDeviceCount()` to debug
Multiple sensors issue	Use `.getAddress()` with sensor ID