Intermediate
30 min
0

Receive real-time alerts about air quality changes using BME688 and PIC18F2515

Your partner in humidity balance and air quality brilliance

Environment 3 Click with Curiosity HPC

Published Jan 23, 2024

Click board™

Environment 3 Click

Development board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18F2515

Craft environments that strike the perfect balance between comfort and health by using precise humidity and air quality data to inform your adjustments

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Hardware Overview

How does it work?

Environment 3 Click is based on the BME688, air quality MEMS sensor that combines gas, humidity, temperature, and barometric pressure sensing from Bosch Sensortec. The BME688 combines reliable high-precision sensors with wide-ranging gas detection and innovative AI capabilities, enabling users to rapidly develop various applications to improve well-being, lifestyle, and sustainability. It offers reduced power consumption, improved accuracy specifications, and a configurable host interface for the fastest data transfer. It covers extended operating pressure, humidity, and temperature ranges from 300-1100hPa, 0-100%RH and from -40°C to +85°C with the accuracy of ±3%RH and ±0.5°C. The BME688 supports a full suite of operational modes, which provides vast flexibility in optimizing

the device for power consumption, resolution, and filter performance. Additionally, it also has a gas scanner function; it can detect Volatile Organic Compounds (VOCs), Volatile Sulfur Compounds (VSCs), and other gases such as carbon monoxide and hydrogen in the part per billion (ppb) range. In standard configuration, the presence of VSCs is being detected as an indicator for, e.g., bacteria growth, where the gas scanner can be customized for sensitivity, selectivity, data rate, and power consumption. Based on its main features listed above, this Click board is the best choice for indoor and outdoor air quality measurement applications, detection of unusual gases that might indicate leakage or fire, early detection of odors and bad smells, and other various temperature and humidity-related applications. Environment 3 Click

allows using both I2C and SPI interfaces. The selection can be made by positioning SMD jumpers labeled COMM SEL in an appropriate position. 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 BME688 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled ADDR SEL to an appropriate position marked as 0 or 1. 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. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Environment 3 Click top side image
Environment 3 Click bottom side image

Features overview

Development board

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Curiosity HPC double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

48

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3968

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
RA3
CS
SPI Clock
RB1
SCK
SPI Data OUT
RB2
MISO
SPI Data IN
RB3
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

Environment 3 Click Schematic schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

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

Curiosity HPC front no-mcu image hardware assembly
IR Sense 4 Click front image hardware assembly
MCU DIP 28 hardware assembly
Prog-cut hardware assembly
Curiosity HPC 28pin-DIP - upright/background 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
Necto DIP image step 7 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

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Environment 3 Click driver.

Key functions:

  • environment3_get_all_data - This function reads the temperature, humidity, pressure, and gas resistance data from the sensor

  • environment3_enable_heater - This function enables or disables the gas sensor heater

  • environment3_soft_reset - This function soft-resets the sensor

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 main.c
 * @brief Environment3 Click example
 *
 * # Description
 * This example demonstrates the use of Environment 3 click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver, sets the default configuration, and disables the gas sensor heater.
 *
 * ## Application Task
 * Reads the temperature, humidity, pressure, and gas resistance data from the sensor and 
 * displays all values on the USB UART approximately every second.
 *
 * @note
 * The heater is disabled by default, enable it in the Application Init if you need gas resistance data.
 * Gas resistance data is RAW data, if you need VOCs, please contact Bosch Sensortec for VOC calculation library.
 * The temperature and humidity data don't represent the real environmental data when the heater is enabled.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "environment3.h"

static environment3_t environment3;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;                    /**< Logger config object. */
    environment3_cfg_t environment3_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.

    environment3_cfg_setup( &environment3_cfg );
    ENVIRONMENT3_MAP_MIKROBUS( environment3_cfg, MIKROBUS_1 );
    err_t init_flag  = environment3_init( &environment3, &environment3_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    if ( ENVIRONMENT3_OK != environment3_default_cfg ( &environment3 ) )
    {
        log_error( &logger, " Default Config Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    
    environment3_enable_heater ( &environment3, ENVIRONMENT3_DISABLE );
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float temperature, pressure, humidity;
    uint32_t gas_resistance;
    if ( ENVIRONMENT3_OK == environment3_get_all_data ( &environment3, 
                                                        &temperature, 
                                                        &humidity, 
                                                        &pressure, 
                                                        &gas_resistance ) )
    {
        log_printf( &logger, " Temperature : %.2f C\r\n", temperature );
    
        log_printf( &logger, " Humidity : %.2f %%\r\n", humidity );
        
        log_printf( &logger, " Pressure : %.3f mBar\r\n", pressure );
        
        if ( ENVIRONMENT3_ENABLE == environment3.gas_sett.enable )
        {
            log_printf( &logger, " Gas Resistance : %ld Ohms\r\n", gas_resistance );
            log_printf( &logger, "--------------------------------\r\n" );
        }
        else
        {
            log_printf( &logger, "--------------------------------\r\n" );
            Delay_ms( 1000 );
        }
    }
}

void main ( void ) 
{
    application_init( );

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

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

Additional Support

Resources