Intermediate
30 min

Detect contaminants in the air using ENS160 and PIC18F57Q43

Don't let the air pollution get you down!

Air quality 9 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

Air quality 9 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Best-in-class air-quality sensing solution

A

A

Hardware Overview

How does it work?

Air quality 9 Click is based on the ENS160, an indoor air quality sensor based on metal oxide (MOX) technology with four MOx sensor elements from ScioSense. This sensor has sophisticated fusion algorithms to produce measurement outputs better tuned to human occupants' natural responses. The multi-element TrueVOC™ technology, on which the ENS160 is based, is sensitive to oxidizing gases such as ozone which affect the quality of indoor air, as well as to a wide range of volatile organic compounds (VOCs) such as ethanol, toluene, as well as hydrogen and nitrogen dioxide with superior selectivity and accuracy. The ENS160 complies with worldwide Indoor Air Quality (IAQ) signal standards and is designed for high volume and reliability. For best performance, the sensor must be operated in normal indoor air at -5 to 60°C (typical: 25°C), while relative humidity ranges

from 20 to 80%RH (typical: 50%RH), non-condensing with no aggressive or poisonous gases present. Prolonged exposure to environments outside these conditions can affect the performance and lifetime of the sensor. This Click board™ allows using both I2C and SPI interfaces with a maximum frequency of 1MHz for I2C and 10MHz for SPI communication. The selection can be made by positioning SMD jumpers labeled COMM SEL appropriately. Note that all the jumpers' positions must be on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the ENS160 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled ADDR SEL. This Click board™ also possesses an additional interrupt signal, routed on the INT pin of the mikroBUS™ socket labeled as INT, indicating

the status of the measurement process itself. The ENS160 also requires a supply voltage of 1.8V to work regularly. Therefore, a small LDO regulator, AP2112 from Diodes Incorporated, provides a 1.8V out of mikroBUS™ 3V3 power rail. This LDO can be enabled or disabled through the EN pin routed to the PWM pin of the mikroBUS™ socket, hence, offering a switch operation to turn ON/OFF power delivery to the ENS160. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Air quality 9 Click top side image
Air quality 9 Click lateral side image
Air quality 9 Click bottom side image

Features overview

Development board

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.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
PD4
CS
SPI Clock
PC6
SCK
SPI Data OUT
PC5
MISO
SPI Data IN
PC4
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PA6
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB2
SCL
I2C Data
PB1
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Air quality 9 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Board mapper by product8 hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Software Support

Library Description

This library contains API for Air quality 9 Click driver.

Key functions:

  • airquality9_read_aqi_uba This function reads the Air quality Index per UBA (AQI-UBA).

  • airquality9_read_tvoc This function reads the calculated Total Volatile Organic Compounds (TVOC) concentration per ppb.

  • airquality9_read_eco2 This function reads the calculated Equivalent CO2 (eCO2) concentration per ppm.

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 AirQuality9 Click example
 *
 * # Description
 * This example demonstrates the use of Air Quality 9 Click board by reading and displaying
 * outputs such as eCO2, TVOC and AQI in compliance with worldwide IAQ standards.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger and performs the Click default configuration.
 *
 * ## Application Task
 * Waits for the new data interrupt which triggers once per second, 
 * and then reads the validity status, TVOC, eCO2, and AQI-UBA values. 
 * All values are being displayed on the USB UART where you can track their changes.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "airquality9.h"

static airquality9_t airquality9;
static log_t logger;

/**
 * @brief Air Quality 9 display status validity function.
 * @details This function parses the status validity from status byte and displays it on the USB UART.
 * @param[in] status : Data status byte.
 * @return None.
 * @note None.
 */
void airquality9_display_status_validity ( uint8_t status );

/**
 * @brief Air Quality 9 display aqi uba function.
 * @details This function parses the Air Quality Index per UBA (AQI-UBA) value and displays it on the USB UART.
 * @param[in] aqi_uba : AQI-UBA value.
 * @return None.
 * @note None.
 */
void airquality9_display_aqi_uba ( uint8_t aqi_uba );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    airquality9_cfg_t airquality9_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.
    airquality9_cfg_setup( &airquality9_cfg );
    AIRQUALITY9_MAP_MIKROBUS( airquality9_cfg, MIKROBUS_1 );
    err_t init_flag  = airquality9_init( &airquality9, &airquality9_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( AIRQUALITY9_ERROR == airquality9_default_cfg ( &airquality9 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    if ( airquality9_get_int_pin ( &airquality9 ) )
    {
        uint8_t status, aqi_uba;
        uint16_t tvoc, eco2;
        if ( AIRQUALITY9_OK == airquality9_read_status ( &airquality9, &status ) )
        {
            airquality9_display_status_validity ( status );
        }
        if ( AIRQUALITY9_OK == airquality9_read_tvoc ( &airquality9, &tvoc ) )
        {
            log_printf ( &logger, " TVOC: %u ppb\r\n", tvoc );
        }
        if ( AIRQUALITY9_OK == airquality9_read_eco2 ( &airquality9, &eco2 ) )
        {
            log_printf ( &logger, " ECO2: %u ppm\r\n", eco2 );
        }
        if ( AIRQUALITY9_OK == airquality9_read_aqi_uba ( &airquality9, &aqi_uba ) )
        {
            airquality9_display_aqi_uba ( aqi_uba );
        }
    }
}

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;
}

void airquality9_display_status_validity ( uint8_t status )
{
    switch ( status & AIRQUALITY_STATUS_VALID_FLAG_BITS )
    {
        case AIRQUALITY_STATUS_VALID_NORMAL_OP:
        {
            log_printf ( &logger, " Status: Normal operation\r\n" );
            break;
        }
        case AIRQUALITY_STATUS_VALID_WARM_UP:
        {
            log_printf ( &logger, " Status: Warm-Up phase\r\n" );
            break;
        }
        case AIRQUALITY_STATUS_VALID_INIT_START_UP:
        {
            log_printf ( &logger, " Status: Initial Start-Up phase\r\n" );
            break;
        }
        case AIRQUALITY_STATUS_VALID_INVALID:
        {
            log_printf ( &logger, " Status: Invalid output\r\n" );
            break;
        }
    }
}

void airquality9_display_aqi_uba ( uint8_t aqi_uba )
{
    switch ( aqi_uba )
    {
        case AIRQUALITY9_AQI_UBA_EXELLENT:
        {
            log_printf ( &logger, " AQI-UBA Rating: Exellent\r\n" );
            log_printf ( &logger, " Recommendation: Target\r\n" );
            log_printf ( &logger, " Exposure Limit: No limit\r\n\n" );
            break;
        }
        case AIRQUALITY9_AQI_UBA_GOOD:
        {
            log_printf ( &logger, " AQI-UBA Rating: Good\r\n" );
            log_printf ( &logger, " Recommendation: Sufficient ventilation\r\n" );
            log_printf ( &logger, " Exposure Limit: No limit\r\n\n" );
            break;
        }
        case AIRQUALITY9_AQI_UBA_MODERATE:
        {
            log_printf ( &logger, " AQI-UBA Rating: Moderate\r\n" );
            log_printf ( &logger, " Recommendation: Increased ventilation - Search for sources\r\n" );
            log_printf ( &logger, " Exposure Limit: <12 months\r\n\n" );
            break;
        }
        case AIRQUALITY9_AQI_UBA_POOR:
        {
            log_printf ( &logger, " AQI-UBA Rating: Poor\r\n" );
            log_printf ( &logger, " Recommendation: Intensified ventilation - Search for sources\r\n" );
            log_printf ( &logger, " Exposure Limit: <1 month\r\n\n" );
            break;
        }
        case AIRQUALITY9_AQI_UBA_UNHEALTHY:
        {
            log_printf ( &logger, " AQI-UBA Rating: Unhealthy\r\n" );
            log_printf ( &logger, " Recommendation: Use only if unavoidable - Intensified ventilation\r\n" );
            log_printf ( &logger, " Exposure Limit: No limit\r\n\n" );
            break;
        }
        default:
        {
            log_printf ( &logger, " AQI-UBA Rating: Unknown\r\n\n" );
            break;
        }
    }
}

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

Additional Support

Resources

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