CCS811 digital gas sensor and micro:bit example

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.

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

Schematics/Layout

Remember and connect WAKE to gnd

microbit and CCS811

Code

Again we use a library –

And this ios the out of the box example

[codesyntax lang=”cpp”]

#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);
}

[/codesyntax]

Output

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

CO2: 400ppm, TVOC: 0ppb Temp:35.34
CO2: 400ppm, TVOC: 0ppb Temp:34.42
CO2: 400ppm, TVOC: 0ppb Temp:34.04
CO2: 770ppm, TVOC: 56ppb Temp:32.90
CO2: 400ppm, TVOC: 0ppb Temp:32.53
CO2: 400ppm, TVOC: 0ppb Temp:31.67
CO2: 672ppm, TVOC: 41ppb Temp:30.59
CO2: 476ppm, TVOC: 11ppb Temp:27.43
CO2: 588ppm, TVOC: 28ppb Temp:29.09
CO2: 400ppm, TVOC: 0ppb Temp:30.95
CO2: 400ppm, TVOC: 0ppb Temp:31.67

Links

ccs811 datasheet

CJMCU-811 CCS811 Air Quality Gas Sensor