node-red-contrib-scd4x

Node-RED node for reading measurements from Sensirion SCD40 and SCD41, the CO2, temperature, and humidity sensors.

Uses scd4x-node.

Usage

Find the scd4x node in the sensor category in the palette, and use in your flow.

The node replaces the message payload with an object containing the measured values:

{
  co2Concentration: <number>,
  temperature: <number>,
  relativeHumidity: <number>
}

Requirements

The SCD4x must be in periodic measurement mode and a measurement must be available when triggering this node.

The permission to read the I2C bus device (e.g. /dev/i2c-1) is required.

Usage in Docker on Raspberry Pi

When starting the Node-RED container, use these options:

• --device /dev/i2c-1 – point to the I2C device to which the SCD4x is connected
• --group-add <id of i2c group> – make the container process run as a member of the i2c group

For example:

docker run -d \
  -p 1880:1880 \
  -v /home/pi/.node-red:/data \
  --device /dev/i2c-1 \
  --group-add 998 \
  --name nodered \
  nodered/node-red