Accurately detect the presence of alcohol vapors with MQ-3 and STM32F407VGT6
Breathe, test, and stay safe!
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
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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.
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.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Clicker 4 for STM32F4 as your development board.
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.
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™.
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.
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
