Intermediate
10 min

Reduce noise pollution with actionable data and insights using MCP4921 and PIC32MZ1024EFH064

Respond promptly to noise-related issues

Noise Click with PIC32MZ clicker

Published Oct 02, 2023

Click board™

Noise Click

Dev. board

PIC32MZ clicker

Compiler

NECTO Studio

MCU

PIC32MZ1024EFH064

Our noise detection solution is engineered to identify and mitigate disruptive noise, fostering quieter and more peaceful environments

A

A

Hardware Overview

How does it work?

Noise Click is based on the MCP4921, a 12-bit DAC with an SPI interface from Microchip. This single-channel DAC has a rail-to-rail output, a fast-setting time, and 450KHz of multiplier mode. The MCP4921 on the Noise Click sets the threshold in 12-bit resolution steps from 0 up to 4096. The noise from the environment this Click board™ receives through the MM034202-11, an analog MEMS microphone from DB Unlimited. It has omnidirectional directivity, a sensitivity of around -42dB, a signal-to-noise ratio of 59dB, and works in a frequency range from 100 up to 10000Hz. This Click board™ also includes two MCP6022s, a rail-to-rail input/output 10MHz Op Amps from Microchip. The operational amplifiers feature wide bandwidth up to 10MHz, low noise, low input offset voltage, and low distortion. The first MCP6022

processes the microphone signal. Then, the amplified voltages pass through the LTC1966, a precision micropower ∆∑ RMS-to-DC converter from Analog Devices. This converter has constant bandwidth independent of the input voltage, flexible rail-to-rail inputs, and outputs and is more accurate than conventional log antilog similar RMS-to-DC converters. After processing with the LTC1966, the signal then goes into the second operational amplifier, which functions as a voltage comparator, from which the interrupt signal originates. To avoid triggering the interrupt hundreds of times per second as ambient noise oscillates near the threshold, a hysteresis circuit is also employed. For that purpose, the Noise Click comes with the MAX6106, a low-cost, micropower, low-dropout, high-output-current voltage

reference of 2.048V from Analog Devices. The Noise Click uses an SPI serial interface to communicate with the host MCU over the mikroBUS™ socket. The LTC1966 RMS-to-DC converter can be turned off with the HIGH logic state on the EN pin of the mikroBUS™ socket. No matter the logic state on the enable pin, the voltage levels can still be monitored over the AN pin. When the ambient noise reaches the set threshold, the interrupt INT pin is pulled HIGH. 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.

Noise Click top side image
Noise Click bottom side image

Features overview

Development board

PIC32MZ Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32MZ microcontroller with FPU from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access anywhere and under

any circumstances. Each part of the PIC32MZ Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC32MZ Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Micro-B connection can provide up to 500mA of current, which is more than enough to operate all onboard

and additional modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC32MZ Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

PIC32MZ clicker double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

1024

Silicon Vendor

Microchip

Pin count

64

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

Analog Output
RE4
AN
Enable
RE5
RST
SPI Chip Select
RG9
CS
SPI Clock
RG6
SCK
NC
NC
MISO
SPI Data IN
RG8
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RB5
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Noise Click Schematic schematic

Step by step

Project assembly

PIC32MZ clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the PIC32MZ clicker as your development board.

PIC32MZ clicker front image hardware assembly
Thermo 26 Click front image hardware assembly
Prog-cut hardware assembly
Micro B Connector clicker - 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
Flip&Click PIC32MZ 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. 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 Noise Click driver.

Key functions:

  • noise_set_cmd_reg - This function sets command register

  • noise_set_state - This function switches click ON or OFF

  • noise_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 
 * \brief Noise click example
 * 
 * # Description
 * This example performs an ambient noise monitoring using the Noise click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Device initialization.
 * 
 * ## Application Task  
 * Reads the voltage from AN pin which presents the noise level and displays it
 * on the USB UART every 5ms. If the noise is above predefined threshold
 * (25 percents of max noise, i.e. about 0.4V) an alarm message is being shown.
 * 
 * @note 
 * We recommend using the SerialPlot tool for data visualizing.
 * 
 * \author MikroE Team
 *
 */
#include "board.h"
#include "log.h"
#include "noise.h"

static noise_t noise;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;
    noise_cfg_t cfg;

    /** 
     * 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.
    noise_cfg_setup( &cfg );
    NOISE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    noise_init( &noise, &cfg );

    noise_default_cfg( &noise );
}

void application_task ( void )
{
    float voltage = 0;
    if ( NOISE_OK == noise_read_an_pin_voltage ( &noise, &voltage ) )
    {
        log_printf( &logger, "%.3f\r\n", voltage );
    }
    if ( noise_check_int_pin( &noise ) )
    {
        log_printf( &logger, " Sound overlimit detected!\r\n" );
    }
    Delay_ms ( 5 );
}

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
/*!
 * \file 
 * \brief Noise click example
 * 
 * # Description
 * This example performs an ambient noise monitoring using the Noise click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Device initialization.
 * 
 * ## Application Task  
 * Reads the voltage from AN pin which presents the noise level and displays it
 * on the USB UART every 5ms. If the noise is above predefined threshold
 * (25 percents of max noise, i.e. about 0.4V) an alarm message is being shown.
 * 
 * @note 
 * We recommend using the SerialPlot tool for data visualizing.
 * 
 * \author MikroE Team
 *
 */
#include "board.h"
#include "log.h"
#include "noise.h"

static noise_t noise;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;
    noise_cfg_t cfg;

    /** 
     * 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.
    noise_cfg_setup( &cfg );
    NOISE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    noise_init( &noise, &cfg );

    noise_default_cfg( &noise );
}

void application_task ( void )
{
    float voltage = 0;
    if ( NOISE_OK == noise_read_an_pin_voltage ( &noise, &voltage ) )
    {
        log_printf( &logger, "%.3f\r\n", voltage );
    }
    if ( noise_check_int_pin( &noise ) )
    {
        log_printf( &logger, " Sound overlimit detected!\r\n" );
    }
    Delay_ms ( 5 );
}

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

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