Beginner
10 min

Enhance your safety by monitoring hydrogen gas leaks using MQ-8 and PIC18LF45K22

Precise hydrogen sensing for all

HYDROGEN Click with EasyPIC v7a

Published Jun 20, 2023

Click board™

HYDROGEN Click

Development board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18LF45K22

By providing early detection of hydrogen leaks, this detection solution helps prevent the potential risks of fire, explosions, and asphyxiation, safeguarding the well-being of individuals and protecting property

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Hardware Overview

How does it work?

Hydrogen Click is based on the MQ-8, a hydrogen (H2) sensor from Zhengzhou Winsen Electronics Technology, which detects hydrogen's presence and concentration in the air. The gas sensing layer on the MQ-8 sensor unit is made of Tin dioxide (SnO2), which has lower conductivity in clean air. The conductivity increases as the levels of hydrogen rise. It has a high sensitivity to hydrogen in a wide range suitable for detecting it in concentrations from 100 to 10.000ppm. Besides a

binary indication of the presence of hydrogen, the MQ-8 also 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 hydrogen concentration; the higher the hydrogen concentration in the air, the higher the output voltage. Hydrogen Click has a small potentiometer that allows you to adjust the load resistance of the sensor circuit, to calibrate

the sensor for the environment in which you'll be using it. This Click board™ can be operated only 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.

HYDROGEN Click hardware overview image

Features overview

Development board

EasyPIC v7a is the seventh generation of PIC development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7a allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC v7a development board

contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-

established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7a is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

EasyPIC v7a double side image

Microcontroller Overview

MCU Card / MCU

PIC18LF45K22

Architecture

PIC

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

1536

Used MCU Pins

mikroBUS™ mapper

Analog Output
RA2
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

HYDROGEN Click Schematic schematic

Step by step

Project assembly

EasyPIC v7a front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7a as your development board.

EasyPIC v7a front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyPIC v7a 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 Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for Hydrogen Click driver.

Key functions:

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

  • hydrogen_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 Hydrogen 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 "hydrogen.h"

static hydrogen_t hydrogen;   /**< Hydrogen Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    hydrogen_cfg_t hydrogen_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.

    hydrogen_cfg_setup( &hydrogen_cfg );
    HYDROGEN_MAP_MIKROBUS( hydrogen_cfg, MIKROBUS_1);
    if ( hydrogen_init( &hydrogen, &hydrogen_cfg ) == ADC_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

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

void application_task ( void ) {
    uint16_t hydrogen_an_value = 0;

    if ( hydrogen_read_an_pin_value ( &hydrogen, &hydrogen_an_value ) != ADC_ERROR ) {
        log_printf( &logger, " ADC Value : %u\r\n", hydrogen_an_value );
    }

    float hydrogen_an_voltage = 0;

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

    Delay_ms( 1000 );
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources