Overview

The ds18b20 node reads temperature from DS18B20 digital temperature sensors. These waterproof, precise sensors use the 1-Wire protocol, allowing multiple sensors on a single GPIO pin. Perfect for environmental monitoring, HVAC, and liquid temperature measurement.

±0.5°C

Accuracy

-55 to +125°C

Range

12-bit

Resolution

750ms

Conversion

Wiring

Connection

VCC (Red) → 3.3V

GND (Black) → GND

DATA (Yellow) → GPIO 4

Add 4.7kΩ pull-up resistor between DATA and VCC

Enable 1-Wire

# Add to /boot/config.txt
dtoverlay=w1-gpio

# Then reboot
sudo reboot

Properties

Property	Type	Default	Description
sensorId	string	"" (all)	Specific sensor ID or empty for all sensors
interval	number	10	Reading interval in seconds
unit	string	"C"	Temperature unit: "C", "F", or "K"
precision	number	2	Decimal places in output

Output

{
  "payload": 23.5,
  "sensorId": "28-00000abcdef1",
  "unit": "°C",
  "timestamp": 1640000000000,
  "raw": 23500
}

Example: Multi-Sensor Temperature Monitor

Monitor temperatures from multiple DS18B20 sensors and display on dashboard.

ds18b20 → switch (by ID) → gauge

[
  {
    "id": "ds18b20-all",
    "type": "ds18b20",
    "sensorId": "",
    "interval": 10,
    "unit": "C"
  },
  {
    "id": "route-sensors",
    "type": "switch",
    "property": "sensorId",
    "rules": [
      { "v": "28-00000abcdef1" },
      { "v": "28-00000abcdef2" }
    ]
  },
  {
    "id": "gauge-indoor",
    "type": "ui_gauge",
    "name": "Indoor Temp",
    "min": 0,
    "max": 50
  }
]

Related Nodes

1-wire

Low-level 1-Wire access

dht22

Temp + humidity sensor

chart

Visualize temperature history