@wigglywire/node-red-sht4x 0.1.2

Node-RED node to read temperature and humidity from Sensirion SHT4x sensors over I2C

npm install @wigglywire/node-red-sht4x

@wigglywire/node-red-sht4x

A Node-RED node for interfacing with the Sensirion SHT4x temperature and humidity sensor over I²C. This node reads temperature and relative humidity from an SHT4x sensor when triggered by an input message. Temperature units are user-selectable between °C and °F.

Features:

• I²C communication with SHT4x
• Temperature output in:
  • Degrees Celsius (°C)
  • Degrees Fahrenheit (°F)
• Relative humidity output (%RH)
• Triggered by standard Node-RED input message
• Designed for Raspberry Pi and other Linux SBCs

Installation:

From Node-RED (Recommended):

1. Open Node-RED

2. Go to Menu → Manage Palette

3. Select the Install tab

4. Search for:

   @wigglywire/node-red-sht4x
   

5. Click Install

From Command Line:

Run the following in your Node-RED user directory (typically ~/.node-red):

npm install @wigglywire/node-red-sht4x

Restart Node-RED.

Hardware Requirements

• Sensirion SHT4x Temperature & Humidity Sensor
• I²C enabled system (e.g., Raspberry Pi)

Enable I²C (Raspberry Pi)

sudo raspi-config

Navigate to:

Interface Options → I2C → Enable

Install I²C tools if needed:

sudo apt install -y i2c-tools

Verify the sensor is detected:

i2cdetect -y 1

The SHT4x default I²C address is:

0x44

Node Configuration

Properties

I²C Bus - Typically 1 on Raspberry Pi

I²C Address - Default: 0x44

Temperature Unit - °C or °F

Usage

1. Add an Inject node.
2. Connect it to the SHT4x node.
3. Connect a Debug node to view the output.
4. Deploy.
5. Click Inject.

https://github.com/user-attachments/assets/ccbb2455-8f3e-49f4-932e-048e20e833b9

Output

When triggered, the node outputs a message object:

{
  "payload": {
    "temperature": 23.41,
    "humidity": 45.12,
    "unit": "C"
  }
}

If Fahrenheit is selected:

{
  "payload": {
    "temperature": 74.14,
    "humidity": 45.12,
    "unit": "F"
  }
}

Dependencies

• Node.js ≥ 16
• Node-RED ≥ 3.x
• I²C support on host device