Monitor indoor air quality with RRH46410 and PIC32MZ2048EFM100
Total volatile organic compounds (TVOC), indoor air quality (IAQ), and estimated carbon dioxide (eCO2) sensing solution
Published Dec 31, 2024
Click board™
Air Quality 12 Click
Dev. board
Curiosity PIC32 MZ EF
Compiler
NECTO Studio
MCU
PIC32MZ2048EFM100
Indoor air quality monitor based on AI-enhanced gas sensing technology perfect for homes, offices, HVAC systems, and air purifiers
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Hardware Overview
How does it work?
Air Quality 12 Click is based on the RRH46410, a digital gas sensor module from Renesas designed for monitoring indoor air quality. This module integrates advanced sensing technology to detect and measure total volatile organic compounds (TVOC), indoor air quality (IAQ), and estimated carbon dioxide levels (eCO2) with precision and reliability. Tailored for indoor air monitoring applications, this sensor module combines a MEMS gas sensing element, a CMOS signal conditioning IC, and an onboard microcontroller, offering a complete, self-contained gas detection solution. Thanks to its low operating power consumption and multiple operational methods, this solution is ideally suited for applications such as indoor air quality monitoring, ensuring healthy environments in homes, offices, and public buildings, and detection of hazardous materials and harmful fumes, including those from construction materials, and automation of air quality-based devices. The RRH46410's MEMS gas sensing element incorporates a heater on a silicon-based structure and a metal oxide (MOx) chemiresistor, capable of
detecting changes in conductivity caused by gas concentrations. The module's signal conditioner regulates the sensor temperature and processes MOx conductivity measurements, while the integrated microcontroller generates a calibrated digital output, eliminating the need for complex data processing on the user's host MCU. The RRH46410 stands out for its intelligent design, leveraging artificial intelligence (AI) and a machine-learning algorithm to produce accurate air quality measurements. It can detect TVOC contaminants based on established international indoor air quality standards while responding effectively, though not selectively, to hydrogen (H₂) within the parts-per-million range. Its fast response time, measured in seconds, ensures near-instantaneous readings without requiring direct airflow onto the sensor. However, while it can detect gases like carbon monoxide (CO), it is not approved for safety-critical applications and should not be relied upon for life-saving use cases. This Click board™ supports both UART and I2C interfaces for communication with the host MCU. The UART interface operates at a
default baud rate of 115200bps, enabling efficient data transmission and exchange, while the I2C interface supports clock frequencies of up to 400kHz for flexible integration with various systems. In addition to the interface pins, the board includes other control pins such as the RST pin for resetting the module, the INT pin for real-time alerts (set HIGH when data is available and LOW after data is read), and the GP1 pin, which controls the red GP1 LED. This user-configurable LED serves as a visual indicator for various scenarios based on the user's needs. The board also features two unpopulated pins labeled GP3 and GP4, which are general-purpose I/O pins configured as always-inputs and lacking internal pull-ups, providing additional versatility for custom applications. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. It also comes equipped with a library containing functions and example code that can be used as a reference for further development.
Features overview
Development board
Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand
functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,
which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
2048
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
524288
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 Curiosity PIC32 MZ EF 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 12 Click driver.
Key functions:
airquality12_get_sensor_info- This function reads the device product ID, firmware version, and tracking number.airquality12_get_int_pin- This function returns the INT pin logic state.airquality12_get_measurement- This function reads the sensor measurement results.
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 main.c
* @brief Air Quality 12 Click example
*
* # Description
* This example demonstrates the use of Air Quality 12 Click board by reading the
* IAQ 2nd Gen measurements and displays the results on the USB UART.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and configures the Click board to the default configuration.
* Then it reads the sensor product ID, firmware version, and the 48-bit tracking number.
*
* ## Application Task
* Checks the data ready interrupt pin and then reads the IAQ 2nd Gen measurements
* and displays the results on the USB UART. The GP1 LED turns ON during the data reading.
* The data sample rate is set to 3 seconds for the IAQ 2nd Gen operating mode, and the first
* 100 samples upon startup should be ignored since the sensor is in the warm-up phase.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "airquality12.h"
static airquality12_t airquality12;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
airquality12_cfg_t airquality12_cfg; /**< Click config object. */
/**
* 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.
airquality12_cfg_setup( &airquality12_cfg );
AIRQUALITY12_MAP_MIKROBUS( airquality12_cfg, MIKROBUS_1 );
if ( AIRQUALITY12_OK != airquality12_init( &airquality12, &airquality12_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( AIRQUALITY12_ERROR == airquality12_default_cfg ( &airquality12 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
airquality12_info_t info;
if ( AIRQUALITY12_OK == airquality12_get_sensor_info ( &airquality12, &info ) )
{
log_printf( &logger, " ---- Sensor info ----\r\n" );
log_printf( &logger, " Product ID: 0x%.4X\r\n", info.product_id );
log_printf( &logger, " FW version: %u.%u.%u\r\n", ( uint16_t ) info.fw_ver_major,
( uint16_t ) info.fw_ver_minor,
( uint16_t ) info.fw_ver_patch );
log_printf( &logger, " Tracking number: 0x%.2X%.2X%.2X%.2X%.2X%.2X\r\n",
( uint16_t ) info.tracking_num[ 5 ], ( uint16_t ) info.tracking_num[ 4 ],
( uint16_t ) info.tracking_num[ 3 ], ( uint16_t ) info.tracking_num[ 2 ],
( uint16_t ) info.tracking_num[ 1 ], ( uint16_t ) info.tracking_num[ 0 ] );
log_printf( &logger, " ---------------------\r\n" );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
airquality12_results_t results = { 0 };
if ( airquality12_get_int_pin ( &airquality12 ) )
{
airquality12_set_gp1_pin ( &airquality12, 1 );
if ( AIRQUALITY12_OK == airquality12_get_measurement ( &airquality12, &results ) )
{
log_printf ( &logger, " Sample number: %u\r\n", ( uint16_t ) results.sample_num );
log_printf ( &logger, " IAQ: %.1f\r\n", results.iaq );
log_printf ( &logger, " TVOC: %.2f mg/m^3\r\n", results.tvoc );
log_printf ( &logger, " ETOH: %.2f ppm\r\n", results.etoh );
log_printf ( &logger, " ECO2: %u ppm\r\n", results.eco2 );
log_printf ( &logger, " rel_IAQ: %u\r\n\n", results.rel_iaq );
}
airquality12_set_gp1_pin ( &airquality12, 0 );
}
}
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
