Monitor indoor air quality with RRH46410 and PIC18F57Q43

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.

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.