Beginner
10 min

Accurately detect the presence of alcohol vapors with MQ-3 and STM32F407VGT6

Breathe, test, and stay safe!

Alcohol Click with Clicker 4 for STM32F4

Published Dec 29, 2023

Click board™

Alcohol Click

Dev Board

Clicker 4 for STM32F4

Compiler

NECTO Studio

MCU

STM32F407VGT6

Develop innovative solutions that feature advanced ethanol gas detection technology

A

A

Hardware Overview

How does it work?

Alcohol Click is based on the MQ-3, an alcohol sensor module from Zhengzhou Winsen Electronics Technology, which detects the presence and concentration of alcohol in the air. The MQ-3 gas sensor comprises a micro AL2O3 ceramic tube, a Tin Dioxide (SnO2) sensitive layer, a measuring electrode, and a heater fixed into a plastic and stainless steel net crust. The heater provides necessary work conditions for the work of sensitive components. It has a high sensitivity to alcohol and

slight to benzine, suitable for detecting alcohol in concentrations from 0.04 to 4mg/l. The MQ-3 provides an analog representation of its concentration in the air sent directly to an analog pin of the mikroBUS™ socket labeled OUT. The analog output voltage the sensor provides varies in proportion to the alcohol concentration; the higher the alcohol concentration in the air, the higher the output voltage. Also, this Click board™ has a built-in potentiometer that allows users to adjust the

Load Resistance of the MQ-3 circuit for optimum performance. This Click board™ can only be operated with a 5V 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.

Alcohol Click hardware overview image

Features overview

Development board

Clicker 4 for STM32F4 is a compact development board designed as a complete solution that you can use to quickly build your own gadgets with unique functionalities. Featuring an STM32F407VGT6 MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core is an STM32F407VGT6 MCU, a powerful microcontroller by STMicroelectronics based on the high-performance

Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the

development board much simpler and, thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution that can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws.

Clicker 4 for STM32F4 double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M4

MCU Memory (KB)

10

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

100

Used MCU Pins

mikroBUS™ mapper

Analog Output
PC4
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
NC
NC
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

Alcohol Click Schematic schematic

Step by step

Project assembly

Clicker 4 for STM32F4 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Clicker 4 for STM32F4 as your development board.

Clicker 4 for STM32F4 front image hardware assembly
Rotary O 2 Click front image hardware assembly
Clicker 4 STM32F4 MB 1 - 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
Clicker 4 for STM32F4 HA 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

Track your results in real time

Application Output

1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for Alcohol Click driver.

Key functions:

alcohol_read_an_pin_value  -  This function reads results of AD conversion of the AN pin.

alcohol_read_an_pin_voltage - This function reads results of AD conversion of the AN pin and converts them to proportional voltage level.

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 Alcohol Click Example.
 *
 * # Description
 * The demo application shows the reading of the adc 
 * values given by the sensors.
 * 
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Configuring clicks and log objects.
 *
 * ## Application Task
 * Reads the adc value and prints in two forms (DEC and HEX).
 * 
 * @author Jelena Milosavljevic
 *
 */

#include "board.h"
#include "log.h"
#include "alcohol.h"

static alcohol_t alcohol;   /**< Alcohol Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    alcohol_cfg_t alcohol_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.

    alcohol_cfg_setup( &alcohol_cfg );
    ALCOHOL_MAP_MIKROBUS( alcohol_cfg, MIKROBUS_1 );
    if ( alcohol_init( &alcohol, &alcohol_cfg ) == ADC_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
}

void application_task ( void ) {
    uint16_t alcohol_an_value = 0;

    if ( alcohol_read_an_pin_value ( &alcohol, &alcohol_an_value ) != ADC_ERROR ) {
        log_printf( &logger, " ADC Value : %u\r\n", alcohol_an_value );
    }

    float alcohol_an_voltage = 0;

    if ( alcohol_read_an_pin_voltage ( &alcohol, &alcohol_an_voltage ) != ADC_ERROR ) {
        log_printf( &logger, " AN Voltage : %.3f[V]\r\n\n", alcohol_an_voltage );
    }

    Delay_ms( 1000 );
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources

Love this project?

'Buy This Kit' button takes you directly to the shopping cart where you can easily add or remove products.