Intermediate
30 min
0

Take control of the air you breathe using MiCS-6814 and STM32L041C6

Take a deep breath comfortably

Air quality 5 Click with Fusion for STM32 v8

Published Aug 29, 2023

Click board™

Air quality 5 Click

Development board

Fusion for STM32 v8

Compiler

NECTO Studio

MCU

STM32L041C6

With real-time alerts and actionable insights, our monitor solution transforms air quality management into a dynamic and responsive process for safer living

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Hardware Overview

How does it work?

Air Quality 5 Click is based on the MiCS-6814, a compact triple MOS sensor from SGX Sensortech with three fully independent sensors. The Click board™ also contains the ADS1015, a low-power 12-bit ADC with Internal reference and a programmable comparator from Texas Instruments. The MiCS-6814 sensor comprises three independent metal oxide sensors heated by three separate heater structures. Chemicals absorbed by the metal oxide surface change the resistive properties of the sensor. The typical baseline resistance may vary a lot from sensor to sensor, which can be affected by the measurement conditions, sensor aging, and several other factors. Therefore, it is recommended to periodically monitor the relative change of the sensing resistance against the baseline resistance. It allows the development of applications that detect relative gas concentration changes rather than measuring the absolute gas concentration values. As mentioned, there are three sensors on

the same die. Each of them reacts with a different type of gas. There is a RED sensor, which reacts with the reducing gas agents, an OX sensor, which reacts with the oxidizing gas agents, and a sensor that reacts with NH3. These sensors provide readings (in ppm) for eight different gasses, which are interesting to monitor in the automotive, industry, or agriculture-polluted atmosphere. Every heating structure is powered from the mikroBUS™ 5V power rail via the resistor recommended by the manufacturer. This ensures the maximum life cycle of the device is achieved since current ratings above the recommended would damage the sensors and heaters. It is recommended to pre-heat the sensors for at least 30 seconds before valid readings can be made. The longer the pre-heat period is, the more accurate the measurement becomes. The changes in the sensor resistance are measured and sampled by the onboard ADC. The ADS1015 ADC has four multiplexed inputs, of which three are

connected to each sensor. The ADC has an internal reference, is simple to operate, offers inputs that can handle voltages across the sensors, and requires a low number of external components. These attributes make it perfectly suitable for this Click board™. In addition, it is possible to change the I2C address of the device. This is done by using the SMD jumper labeled as ADD SEL. This jumper allows the selection of the I2C LSB bit state (0 or 1), allowing more than one Click board™ on the same I2C bus. The ADS1015 IC also has a READY pin, which signals or alerts the host MCU that the conversion is ready for reading. This pin is routed to the mikroBUS™ INT pin and labeled as RDY. More information on configuring and using this pin can be found in the ADS1015 datasheet. Both 5V and 3.3V rails from the mikroBUS™ are used. The ADC is powered by a 3.3V rail, but the sensor requires a 5V rail. Therefore, the Click board™ requires both 3.3V and 5V pins to be supplied with the power.

Air quality 5 Click top side image
Air quality 5 Click bottom side image

Features overview

Development board

Fusion for STM32 v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for STM32 v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Fusion for STM32 v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

48

RAM (Bytes)

8192

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Data Ready
PA15
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PA9
SCL
I2C Data
PA10
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

Air quality 5 Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for STM32 v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for Air Quality 5 Click driver.

Key functions:

  • airq5_write_data - Functions for write data in register

  • airq5_read_data - Functions for read data from register

  • airq5_set_configuration - Functions for configuration

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file 
 * \brief Airquality5 Click example
 * 
 * # Description
 * This application can detect gas pollution for a number of different gases.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes device and configuration chip.
 * 
 * ## Application Task  
 * Reads the values of CO, NH3 and NO2 sensor and logs data on USBUART every 500ms.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "airquality5.h"

// ------------------------------------------------------------------ VARIABLES

static airquality5_t airquality5;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    airquality5_cfg_t cfg;
    airquality5.data_config = 0x8583;

    /** 
     * 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.

    airquality5_cfg_setup( &cfg );
    AIRQUALITY5_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    airquality5_init( &airquality5, &cfg );
}

void application_task ( void )
{
    //  Task implementation.

    uint16_t NO2_sensor_data;
    uint16_t NH3_sensor_data;
    uint16_t CO_sensor_data;
 
    CO_sensor_data = airq5_read_sensor_data( &airquality5, AIRQ5_DATA_CHANNEL_CO );
      
    NO2_sensor_data = airq5_read_sensor_data( &airquality5, AIRQ5_DATA_CHANNEL_NO2 );
    log_printf( &logger, " NO2 data: %d\r\n", NO2_sensor_data );
      
    NH3_sensor_data = airq5_read_sensor_data( &airquality5, AIRQ5_DATA_CHANNEL_NH3 );
    log_printf( &logger, " NH3 data: %d\r\n", NH3_sensor_data );
     
    CO_sensor_data = airq5_read_sensor_data( &airquality5, AIRQ5_DATA_CHANNEL_CO );
    log_printf( &logger," CO data: %d\r\n", CO_sensor_data );
     
    log_printf( &logger, " -------- ");
    Delay_ms( 200 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources