Take control of the air you breathe using MiCS-6814 and STM32L4A6ZG
Take a deep breath comfortably
Published Sep 17, 2024
Click board™
Air quality 5 Click
Dev. board
Nucleo 144 with STM32L4A6ZG MCU
Compiler
NECTO Studio
MCU
STM32L4A6ZG
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.
Features overview
Development board
Nucleo-144 with STM32L4A6ZG MCU board offers an accessible and adaptable avenue for users to explore new ideas and construct prototypes. It allows users to tailor their experience by selecting from a range of performance and power consumption features offered by the STM32 microcontroller. With compatible boards, the
internal or external SMPS dramatically decreases power usage in Run mode. Including the ST Zio connector, expanding ARDUINO Uno V3 connectivity, and ST morpho headers facilitate easy expansion of the Nucleo open development platform. The integrated ST-LINK debugger/programmer enhances convenience by
eliminating the need for a separate probe. Moreover, the board is accompanied by comprehensive free software libraries and examples within the STM32Cube MCU Package, further enhancing its utility and value.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
STMicroelectronics
Pin count
144
RAM (Bytes)
327680
You complete me!
Accessories
Click Shield for Nucleo-144 comes equipped with four mikroBUS™ sockets, with one in the form of a Shuttle connector, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-144 board with no effort. This way, MIKROE allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. Featuring an ARM Cortex-M microcontroller, 144 pins, and Arduino™ compatibility, the STM32 Nucleo-144 board offers limitless possibilities for prototyping and creating diverse applications. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-144 board out of the box, with an additional USB cable connected to the USB mini port on the board. Simplify your project development with the integrated ST-Link debugger and unleash creativity using the extensive I/O options and expansion capabilities. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-144 board with our Click Shield for Nucleo-144, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Nucleo 144 with STM32L4A6ZG MCU 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 5 Click driver.
Key functions:
airq5_write_data- Functions for write data in registerairq5_read_data- Functions for read data from registerairq5_set_configuration- Functions for configuration
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 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 );
}
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
