ESP32 and CCS811 gas sensor example

In this example we will connect a CCS811 gas sensor to an ESP32, first of all lets look at the sensor

The CCS811 is a low-power digital gas sensor solution, which integrates a gas sensor solution for detecting low levels of VOCs typically found indoors, with a microcontroller unit (MCU) and an Analog-to-Digital converter to monitor the local environment and provide an indication of the indoor air quality via an equivalent CO2 or TVOC output over a standard I2C digital interface.

I usually like to find a suitable module or breakout top use a sensor, here is the one I chose.

Features

Integrated MCU
On-board processing
Standard digital interface
Optimised low power modes
IAQ threshold alarms
Programmable baseline
2.7mm x 4.0mm LGA package
Low component count
Proven technology platform

Specs

Parts List

Name	Link
ESP32		Aliexpress link Amazon Ebay
CCS811		Aliexpress link Ebay link Amazon Link
Connecting cables		Aliexpress link Amazon Ebay

Schematics/Layout

Remember and connect WAKE to gnd

Layout

esp32 and CCS811 layout

Schematic

esp32 and CCS811 schematic

Code

Again we use a library this is the adafruit one – you can use the library manager and add this.

And this is the out of the box example

#include "Adafruit_CCS811.h"

Adafruit_CCS811 ccs;

void setup() {
Serial.begin(9600);

Serial.println("CCS811 test");

if(!ccs.begin()){
Serial.println("Failed to start sensor! Please check your wiring.");
while(1);
}

//calibrate temperature sensor
while(!ccs.available());
float temp = ccs.calculateTemperature();
ccs.setTempOffset(temp - 25.0);
}

void loop() {
if(ccs.available()){
float temp = ccs.calculateTemperature();
if(!ccs.readData()){
Serial.print("CO2: ");
Serial.print(ccs.geteCO2());
Serial.print("ppm, TVOC: ");
Serial.print(ccs.getTVOC());
Serial.print("ppb Temp:");
Serial.println(temp);
}
else{
Serial.println("ERROR!");
while(1);
}
}
delay(500);
}

Output

Open the serial monitor – this is what I saw. The higher CO2 level was when I breathed on the sensor

CO2: 954ppm, TVOC: 84ppb Temp:17.12
CO2: 400ppm, TVOC: 0ppb Temp:13.32
CO2: 400ppm, TVOC: 0ppb Temp:14.63
CO2: 889ppm, TVOC: 74ppb Temp:20.24
CO2: 400ppm, TVOC: 0ppb Temp:20.53
CO2: 400ppm, TVOC: 0ppb Temp:19.67
CO2: 400ppm, TVOC: 0ppb Temp:0.93
CO2: 1513ppm, TVOC: 169ppb Temp:0.75
CO2: 501ppm, TVOC: 15ppb Temp:-0.37
CO2: 815ppm, TVOC: 63ppb Temp:26.76
CO2: 400ppm, TVOC: 0ppb Temp:27.10

Links

ccs811 datasheet