30 min

Detect the presence of nearby objects without any physical contact with VCNL4200 and STM32F107VC

Embrace the future of proximity detection

Proximity 3 Click  with Fusion for ARM v8

Published Oct 14, 2023

Click board™

Proximity 3 Click

Development board

Fusion for ARM v8


NECTO Studio



Our proximity detection solution aims to seamlessly integrate technology into your daily life, enhancing convenience and safety



Hardware Overview

How does it work?

Proximity 3 Click is based on the VCNL4200 from Vishaywhich combines matched 940 nm IR emitter and a photodiode for proximity measurement and ambient light sensing. VCNL4200 offers programmable measurement by utilizing the advanced signal processing techniques, allowing the sensor to operate in various conditions. Communication with the microcontroller is done via the I2C interface so that the host controller can set the measurement parameters and request results back from the sensor. Both low and high threshold values for the measured property can also be set via the I2C so that the interrupts can be generated every time the threshold value is exceeded. This allows for the

reduced need of the sensor polling, which can result in better power management. With MikroElektronika library functions, setting up the registers is really easy and the tedious task of initializing the sensor is taken care of with a few simple function calls. More information about the sensor's registers and addresses can be found in the VCNL4200 datasheet. The Filtron™ technology used in the ALS, allows the sensor to match the ambient light spectral sensitivity to human eye response and it's immune to fluorescent light flicker. This ensures the accuracy of the measurements. The maximum detection range is selectable (197 / 393 / 786 / 1573 lux) with highest sensitivity 0.003 lux / step. The proximity sensor

uses advanced ambient and background light cancellation schemes, so it is fairly immune to interferences that might occur in this case. This allows for a quite precise proximity detection. The sensor can work either in 12-bit or 16-bit mode, selectable by I2C command. The click's range is up to 1.5m. VCNL4200 input voltage is 3V3, while the separate 5V supply rail is used to supply power for the IR emitter pulses, generated by the small external P-channel MOSFET (Q1). This way, the power dissipation of the IRED drive is displaced from the chip, and the high-current IRED drive pulses are isolated from the sensitive integrated circuit sections, connected to the 3V3 rail.

Proximity 3 Click top side image
Proximity 3 Click bottom side image

Features overview

Development board

Fusion for ARM v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different ARM® Cortex®-M based MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the Fusion for ARM v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for ARM v8 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.

Fusion for ARM v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M3

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply
I2C Clock
I2C Data
Power Supply

Take a closer look


Proximity 3 Click  Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for ARM v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN 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 image step 7 hardware assembly
Necto image step 8 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 Proximity 3 Click driver.

Key functions:

  • proximity3_write_16 - This function writes data to the desired register

  • proximity3_read_als - This function gets the data returned by the ambient light sensor

  • proximity3_read_proximity - This function returns the proximity

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 Proximity3 Click example
 * # Description
 * This application reads the data from the ambient light sensor
 * and converts the data into digital form using calculations.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initialization driver enable's - I2C, initialize VCNL4100,
 * write configuration register and start write log to Usart Terminal.
 * ## Application Task  
 * This is a example which demonstrates the use of Proximity 3 Click board.
 * Measured distance ( proximity ) and illuminance ( abmient light ) from sensor,
 * results are being sent to the Usart Terminal where you can track their changes.
 * All data logs on usb uart for aproximetly every 3 sec.
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "proximity3.h"

// ------------------------------------------------------------------ VARIABLES

static proximity3_t proximity3;
static log_t logger;
uint16_t result_proximity;
uint16_t result_ambient_light;
uint16_t value_id;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
    log_cfg_t log_cfg;
    proximity3_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.

    proximity3_cfg_setup( &cfg );
    proximity3_init( &proximity3, &cfg );

    // Default startup options for Ambient Light Sensor
    proximity3_write_16( &proximity3, PROXIMITY3_ALS_CONF_REG, PROXIMITY3_ALS_CONF_CONFIG );
    Delay_ms( 10 );

    // Default startup options for Proximity
    proximity3_write_16( &proximity3, PROXIMITY3_PS_CONF1_CONF2_REG, PROXIMITY3_PS_CONF1_CONF2_CONFIG );
    Delay_ms( 10 );
    proximity3_write_16( &proximity3, PROXIMITY3_PS_CONF3_MS_REG, PROXIMITY3_PS_CONF3_MS_CONFIG );
    Delay_ms( 10 );

    // Set the proximity interrupt levels
    proximity3_write_16( &proximity3, PROXIMITY3_PS_THDL_REG, PROXIMITY3_PS_THDL_CONFIG );
    proximity3_write_16( &proximity3, PROXIMITY3_PS_THDH_REG, PROXIMITY3_PS_THDH_CONFIG );

    // Check device ID
    value_id = proximity3_read_16( &proximity3, PROXIMITY3_DEVICE_ID_REG );

    if ( value_id != PROXIMITY3_DEVICE_ID_VALUE )
        log_printf( &logger, "        ERROR" );
        log_printf( &logger, "       Initialization\r\n" );
        log_printf( &logger, "--------------------------\r\n" );


void application_task ( void )
    result_proximity = proximity3_get_distance( &proximity3 );
    Delay_ms( 10 );

    log_printf( &logger, " Proximity:             %d cm\r\n", result_proximity );

    result_ambient_light = proximity3_get_illuminance( &proximity3 );
    log_printf( &logger, " Ambient Light:         %d lux\r\n", result_ambient_light );

    log_printf( &logger, "-----------------------------------------\r\n" );
    Delay_ms( 1000 );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support