Intermediate
10 min

Reduce noise pollution with actionable data and insights using MCP4921 and MK64FN1M0VDC12

Respond promptly to noise-related issues

Noise Click with Clicker 2 for Kinetis

Published Oct 02, 2023

Click board™

Noise Click

Dev Board

Clicker 2 for Kinetis

Compiler

NECTO Studio

MCU

MK64FN1M0VDC12

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

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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

Clicker 2 for Kinetis 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 ARM Cortex-M4F microcontroller, the MK64FN1M0VDC12 from NXP Semiconductors, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a JTAG programmer connector, and two 26-pin headers for interfacing with external electronics. Its compact design with clear and easily recognizable silkscreen markings allows you to build gadgets with unique functionalities and

features quickly. Each part of the Clicker 2 for Kinetis development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the Clicker 2 for Kinetis programming method, using a USB HID mikroBootloader or an external mikroProg connector for Kinetis programmer, the Clicker 2 board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Micro-B cable, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or

using a Li-Polymer battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several user-configurable buttons and LED indicators. Clicker 2 for Kinetis 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.

Clicker 2 for Kinetis dimensions image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

NXP

Pin count

121

RAM (Bytes)

262144

Used MCU Pins

mikroBUS™ mapper

Analog Output
PB2
AN
Enable
PB11
RST
SPI Chip Select
PC4
CS
SPI Clock
PC5
SCK
NC
NC
MISO
SPI Data IN
PC6
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PB13
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

Clicker 2 for PIC32MZ front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Clicker 2 for Kinetis as your development board.

Clicker 2 for PIC32MZ front image hardware assembly
Buck 22 Click front image hardware assembly
Prog-cut hardware assembly
Micro B Connector Clicker 2 - 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 via Debug Mode

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 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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \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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