Accurately detect the presence of alcohol vapors with MQ-3 and PIC18LF25K80
Breathe, test, and stay safe!
Published Jan 23, 2024
Click board™
Alcohol Click
Dev. board
Curiosity HPC
Compiler
NECTO Studio
MCU
PIC18LF25K80
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
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.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
3648
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
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
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 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 );
}
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;
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Gas
