DS18B20 Temperature Sensor

The DS18B20 is a popular digital temperature sensor that uses a 1-wire interface to communicate with microcontrollers like Arduino and Raspberry Pi. It provides precise temperature measurements, ranging from -55°C to +125°C, with a resolution of 9 to 12 bits. This sensor is widely used in applications that require accurate and reliable temperature readings, such as weather stations, home automation, and industrial monitoring systems.

Specifications

• Operating Temperature Range: -55°C to +125°C
• Accuracy: ±0.5°C (from -10°C to +85°C)
• Resolution: 9 to 12 bits (configurable)
• Communication Protocol: 1-Wire
• Supply Voltage: 3.0V to 5.5V
• Output Type: Digital
• Size: TO-92 Package

Pinout

The DS18B20 sensor has three pins for connection:

• Pin 1: Ground (GND)
• Pin 2: Data (DQ) - This is the 1-Wire communication pin
• Pin 3: Power (VCC) - This pin is used to supply power to the sensor (3.0V to 5.5V)

Applications

The DS18B20 is ideal for various temperature-sensing applications:

• Weather Stations: Monitor outdoor and indoor temperature.
• Home Automation: Control heating, ventilation, and air conditioning (HVAC) systems based on temperature.
• Industrial Monitoring: Track temperatures of machines or environments in factories or data centers.
• Battery-Powered Devices: The low power consumption makes it perfect for battery-operated systems.

Key Features

• High Precision: Measures temperature with an accuracy of ±0.5°C between -10°C and +85°C.
• 1-Wire Interface: Allows multiple DS18B20 sensors to be connected on the same data line, making it easy to expand systems.
• Wide Voltage Range: Can operate with a voltage supply of 3.0V to 5.5V.
• Compact Size: The TO-92 package makes it easy to integrate into space-constrained projects.
• Programmable Resolution: You can configure the sensor to return a resolution of 9 to 12 bits.

Wiring Diagram

The DS18B20 uses the 1-wire protocol, allowing multiple sensors to be connected to a single data line. Below is a simple wiring diagram for connecting the DS18B20 to an Arduino:

        +----------------------+
        |   DS18B20 Sensor     |
        |   (TO-92 Package)    |
        +----------------------+
        |   Pin 1: GND         |
        |   Pin 2: DQ (Data)   |
        |   Pin 3: VCC         |
        +----------------------+

        +--------------------+   +------------+
        |   Arduino Board    |   |  4.7kΩ Resistor |
        +--------------------+   +------------+
        |   GND              |-------------------> GND
        |   DQ               |-------------------> Pin 2 (Digital Pin)
        |   VCC              |-------------------> VCC (3.0V to 5.5V)
        +--------------------+   +------------+
    

Sample Code (Arduino)

        // Include the necessary library
        #include 
        #include 

        // Define the pin where the DS18B20 is connected
        #define ONE_WIRE_BUS 2

        // Setup the OneWire and DallasTemperature instances
        OneWire oneWire(ONE_WIRE_BUS);
        DallasTemperature sensors(&oneWire);

        void setup() {
          Serial.begin(9600);
          sensors.begin(); // Start the sensor
        }

        void loop() {
          sensors.requestTemperatures(); // Request temperature reading
          Serial.print("Temperature: ");
          Serial.print(sensors.getTempCByIndex(0)); // Get temperature of the first sensor
          Serial.println(" C");
          delay(1000); // Delay for 1 second
        }
    

Installation Tips

• Use a 4.7kΩ pull-up resistor between the data pin and VCC for stable operation.
• Ensure that the sensor is properly powered, especially if using a low voltage power supply.
• If connecting multiple DS18B20 sensors, use the 1-Wire bus to communicate with each sensor individually.