STM32 Nucleo and CCS911 sensor MBed example

In this example we will connect a CCS811 gas sensor to an STM32 Nucleo and the code example will be written in the MBed compiler, lets look at the sensor

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

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

Source code

#include "mbed.h"
#include "CCS811.h"
 
 
Serial pc(USBTX, USBRX);
 
#ifdef TARGET_UBLOX_EVK_ODIN_W2
CCS811 ccs811(PF_0, PF_1);
#else
CCS811 ccs811(I2C_SDA, I2C_SCL);
#endif
 
 
uint16_t eco2, tvoc;
 
 
void CCS811Callback(void)
{
 
    ccs811.readData(&eco2, &tvoc);
 
    pc.printf("eCO2 reading :%dppm, TVOC reading :%dppb\r\n", eco2, tvoc);
 
}
 
 
int main()
{
    ccs811.init();
    wait(1);
 
    while(1) {
//        ccs811.readstatus(); //0x90 reports everything working, 0x98 measurement ready to be used
        wait(1);
        CCS811Callback();
        wait(1);
    }
}

Output

Open Teraterm and connect to the assigned port of the STM32 nucleo

You should see something like this

Links

ccs811 datasheet