ccs811

Overview

The ccs811 node reads equivalent CO2 (eCO2) and Total Volatile Organic Compounds (TVOC) from the ams CCS811 digital gas sensor via I2C. This sensor uses a metal oxide (MOX) element to detect a wide range of VOCs and estimate CO2 levels, making it essential for indoor air quality monitoring and ventilation control.

Wiring (I2C)

Properties

Output

{
  "payload": {
    "eCO2": 650,
    "TVOC": 34
  },
  "eCO2": 650,
  "TVOC": 34,
  "baseline": 41339,
  "timestamp": 1640000000000
}

eCO2 Levels Reference

Example: Indoor Air Quality with Alerts

Monitor air quality and send notifications when CO2 levels indicate poor ventilation.

// Function node: Air quality assessment
var eCO2 = msg.eCO2;
var tvoc = msg.TVOC;

var level, color, action;

if (eCO2 < 600) {
    level = "excellent";
    color = "green";
    action = "none";
} else if (eCO2 < 1000) {
    level = "good";
    color = "yellow";
    action = "none";
} else if (eCO2 < 2500) {
    level = "poor";
    color = "orange";
    action = "open_window";
} else {
    level = "unhealthy";
    color = "red";
    action = "ventilate_now";
}

// Only alert on state changes
var prevLevel = flow.get('aqLevel') || "excellent";
flow.set('aqLevel', level);

msg.payload = {
    eCO2: eCO2,
    tvoc: tvoc,
    level: level,
    action: action,
    changed: level !== prevLevel
};

// Only forward if level changed
if (level !== prevLevel) return msg;
return null;

Use Cases