Ensure the air you breathe is of the highest quality using SGP30 and STM32F302VC
See the unseen, breathe the pure
Published Jul 22, 2025
Click board™
Air quality 4 Click
Dev. board
CLICKER 4 for STM32F302VCT6
Compiler
NECTO Studio
MCU
STM32F302VC
From homes to workplaces, our air quality monitor solution seamlessly integrates into any environment, providing real-time insights for a safer, cleaner lifestyle
A
A
Hardware Overview
How does it work?
Air Quality 4 Click is based on the SGP30 from Sensirion, a multi-pixel gas sensor for indoor applications. This sensor is a system of several metal-oxide sensing elements on a chip (pixels), used to measure and process readings of various gasses in the air and output them in the form of two complementary air quality readings - Total Volatile Organic Compounds (TVOC) [ppb] and CO2 equivalent signal [ppm]. The traditional metal-oxide (MOX) sensors suffer from sensitivity and responsiveness degradation after siloxane exposure. Siloxanes are compounds commonly found in the air, negatively affecting the MOX sensors. To overcome this problem, the SGP30 sensors use the advanced MOXSens® Technology, which provides unmatched robustness against siloxane contamination. This results in unprecedented long-term stability and accuracy. The SGP30 uses a dynamic baseline compensation algorithm and calibration parameters to record TVOC and CO2eq properties accurately. These baseline values of the compensation algorithm
can be stored externally and read back into the device with the appropriate I2C commands and can be used in the event of power down or restart. For the first 15 seconds after the I2C initialization command, the sensor is in an initialization phase of collecting sensor measurements and baseline compensation data. When the measurement command is attempted, it will return fixed values of 400 ppm CO2eq and 0 ppb TVOC. The device also allows air humidity corrections over the results for both the compensated and raw values. However, an absolute humidity sensor should be used for obtaining the humidity reading. Readings from SHT click or similar humidity-measuring devices can be used for this purpose. The appropriate I2C command will store the value in the on-chip memory and perform the corrections accordingly. Additional components on Air Quality 4 clicks are used to provide necessary voltage levels for the SGP30 sensor IC. This sensor has a common voltage level of 1.8V, so to provide proper communication with 3.3V and 5V capable MCUs, a
small LDO voltage regulator has to be used, along with the level shifter, which provides the required logic voltage levels. The SPX3819M5, a small 500mA LDO voltage regulator, provides a power supply of 1.8V for the SGP30. The PCA9306 dual bidirectional I2C bus and SMBus voltage level shifter are used for the level shifting. This level shifter IC allows shifting (converting) the I2C signal levels to the voltage level selected by the VCC SEL onboard SMD jumper. This allows 3.3V and 5V capable MCUs to be interfaced with the Air quality 4 Click. More detailed information about all the available I2C commands can be found in the SGP30 datasheet. However, all the functions and commands necessary to perform air quality readings and functions used to calculate H2 and Ethanol concentration levels are contained within the Air Quality 4 click libraries provided with this click board™. Their usage is demonstrated in the included example application, which can be used as a reference for a custom application design.
Features overview
Development board
Clicker 4 for STM32F3 is a compact development board designed as a complete solution, you can use it to quickly build your own gadgets with unique functionalities. Featuring a STM32F302VCT6, four mikroBUS™ sockets for Click boards™ connectivity, power managment, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core, there is a STM32F302VCT6 MCU, a powerful microcontroller by STMicroelectronics, based on the high-
performance Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the development
board much simpler and thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution which can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws. For most applications, a nice stylish casing is all that is needed to turn the Clicker 4 development board into a fully functional, custom design.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
40960
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the CLICKER 4 for STM32F302VCT6 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for Air Quality 4 Click driver.
Key functions:
air_quality4_soft_reset- This function calls general reset witch resets all states on the chipair_quality4_get_co2_and_tvoc- This function writes 2 bytes CO2 data and 2 bytes TVOC data without CRC dataair_quality4_get_h2_and_ehtoh- This function writes 2 bytes H2 data and 2 bytes EthOH data without CRC data
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* \file
* \brief AirQuality4 Click example
*
* # Description
* This application measures the amount of substances in air and air quality and logs the results.
*
* The demo application is composed of two sections :
*
* ## Application Init
* nitializes Click driver and gets ID data.
*
* ## Application Task
* Performs measurements of air concentracion for H2, EthOH, CO2 and TVOC data.
* Results of measurement shows on USBUART.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "airquality4.h"
// ------------------------------------------------------------------ VARIABLES
static airquality4_t airquality4;
static log_t logger;
static uint8_t buffer_data[ 6 ];
static uint16_t data_buffer[ 2 ];
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
airquality4_cfg_t cfg;
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, "---- Application Init ----" );
// Click initialization.
airquality4_cfg_setup( &cfg );
AIRQUALITY4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
airquality4_init( &airquality4, &cfg );
airquality4_default_cfg( &airquality4 );
}
void application_task ( void )
{
air_quality4_get_h2_and_ethon( &airquality4, data_buffer);
log_printf( &logger, "H2 value is: %u\n", data_buffer[ 0 ] );
log_printf( &logger, "EthOH value is: %u\n", data_buffer[ 1 ] );
air_quality4_set_baseline( &airquality4 );
air_quality4_get_co2_and_tvoc( &airquality4, &data_buffer[ 0 ] );
log_printf( &logger, "CO2 value is: %u\n", data_buffer[ 0 ] );
log_printf( &logger, "TVOC value is: %u\n\n", data_buffer[ 1 ] );
Delay_ms ( 1000 );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Gas
