How to Use DS18B20: Examples, Pinouts, and Specs

The DS18B20 is a precision digital temperature sensor that offers a convenient way to measure temperature in a wide range of applications. Manufactured by ELEGOO, this sensor is known for its ease of use with microcontrollers such as the Arduino UNO. It uses the 1-Wire protocol, which minimizes the number of pins required for operation, allowing multiple DS18B20 sensors to be connected in parallel on the same data line.

• Home temperature monitoring systems
• Industrial temperature control
• HVAC systems
• Refrigeration and freezer temperature monitoring
• Aquarium or terrarium temperature control
• Food temperature monitoring

• Supply Voltage: 3.0V to 5.5V
• Operating Temperature Range: -55°C to +125°C (-67°F to +257°F)
• Accuracy: ±0.5°C (from -10°C to +85°C)
• Resolution: Selectable from 9 to 12 bits
• Unique 64-bit Serial Code: For multi-sensor networks
• Conversion Time: 750ms at 12-bit resolution

1. Connect the GND pin to the ground of the power supply.
2. Connect the VDD pin to a 3.0V to 5.5V power supply.
3. Connect the DQ pin to a digital input/output pin on your microcontroller.
4. Use a 4.7kΩ pull-up resistor on the DQ line to ensure proper communication.

• Ensure that the power supply is stable and within the specified voltage range.
• Use the 1-Wire protocol for communication with the microcontroller.
• When using long wires or multiple sensors, consider the effects of parasitic capacitance on the data line.
• Avoid placing the sensor near heat-generating components to prevent false readings.
• For outdoor applications, ensure the sensor is adequately protected from the elements.

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

// Data wire is connected to Arduino digital pin 2
#define ONE_WIRE_BUS 2

// Setup a oneWire instance to communicate with any OneWire device
OneWire oneWire(ONE_WIRE_BUS);

// Pass oneWire reference to DallasTemperature library
DallasTemperature sensors(&oneWire);

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

void loop() {
  sensors.requestTemperatures(); // Send command to get temperatures
  float temperatureC = sensors.getTempCByIndex(0);
  Serial.print("Temperature is: ");
  Serial.print(temperatureC);
  Serial.println("°C");
  delay(1000); // Wait 1 second before next reading
}

• Inaccurate Temperature Readings: Ensure the sensor is not placed near heat sources and that the correct pull-up resistor is used.
• No Data on the Data Line: Check connections and ensure the pull-up resistor is in place. Also, verify that the correct pin is defined in the code.
• Multiple Sensors Interfering: Ensure each sensor has a unique address and that the bus is not overloaded.

• Double-check wiring, especially the pull-up resistor on the DQ line.
• Use the sensors.getAddress() function to verify the unique address of each sensor.
• Reduce the length of the data line or use a lower value pull-up resistor if long cables are used.

Q: Can the DS18B20 be powered parasitically? A: Yes, the DS18B20 can be powered parasitically by connecting the VDD pin to the DQ line through a pull-up resistor.

Q: How many DS18B20 sensors can be connected on the same data line? A: There is no strict limit, but practical considerations like power supply stability and data line capacitance typically allow for around 10-20 sensors.

Q: How do I read the temperature from multiple sensors? A: Each sensor has a unique address. Use the DallasTemperature library functions to read each sensor by its address.

Q: What is the purpose of the unique 64-bit serial code? A: The unique code allows multiple DS18B20 sensors to be used on the same 1-Wire bus without address conflicts, enabling individual sensor identification and communication.