30 min

Close-range proximity sensing based on the VCNL3036X01 and STM32L442KC

Very close to you!

Proximity 18 Click with UNI-DS v8

Published Mar 05, 2023

Click board™

Proximity 18 Click

Development board



NECTO Studio



Detect nearby objects without touching it



Hardware Overview

How does it work?

Proximity 18 Click is based on the VCNL3036X01, a close-range digital proximity sensor from Vishay Semiconductors. The VCNL3036X01 integrates a proximity sensor, a mux, and a driver for three external LEDs (green LED VLMTG1300 and dual-pack IR, and Red LED VSMD66694) located near the chip on the board, alongside photodiodes, amplifiers, and analog to digital conversion circuits into a single CMOS chip. Proximity 18 Click provides absolute distance measurement that is accurate up to 50cm. The VCNL3036X01 supports various basic proximity function settings such as duty ratio, integration time, interrupt, proximity enable, disable, and persistence, all handled by the register configurations. Besides Normal operation mode, it also simplifies the use of proximity detection mode that outputs

HIGH / LOW levels, saving loading from the host selected via register settings. Proximity 18 Click communicates with an MCU using the standard I2C 2-wire interface to read data and configure settings, supporting Fast Mode up to 400kHz. The command register controls all operations. The simple command structure helps users program the operation setting easily and latch the light data from VCNL3036X01. It is simple for the host MCU to access proximity output data via the I2C interface without extra software algorithms. A further benefit is that the VCNL3036X01 also provides a programmable interrupt feature of individual high and low thresholds, resulting in the best utilization of MCU resources and power routed to the INT pin on the mikroBUS™ socket. If the interrupt function is enabled, the host reads the proximity

output data from VCNL3036X01, which saves the host loading from periodically-read proximity data. More than that, an interrupt flag indicates the interrupt behavior triggered under different conditions. Once the host reads the result, the interrupt is cleared, and the ranging sequence can repeat. This Click board™ can operate with both 3.3V and 5V logic voltage levels. It should be highlighted that the VCNL3036X01 works exclusively at 3.3V, so it is necessary to perform appropriate logic voltage level conversion before using MCUs with different logic levels. 5V is used only for powering the LEDs. 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.

Proximity 18 Click top side image
Proximity 18 Click lateral side image
Proximity 18 Click bottom side image

Features overview

Development board

UNI-DS 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 STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR 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, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS 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. UNI-DS 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.

UNI-DS v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

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 18 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 UNI-DS 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 18 Click driver.

Key functions:

  • proximity18_start_measurement This function starts the measurement by setting the one-time trigger bit in the PS_CONF3_MS register.

  • proximity18_wait_for_data_ready This function waits for the MPX data ready interrupt flag.

  • proximity18_read_proximity This function reads the proximity data from all three sensors.

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 Proximity 18 Click example
 * # Description
 * This example demonstrates the use of Proximity 18 click board by reading and 
 * displaying the proximity data on the USB UART.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and logger, and performs the click default configuration.
 * ## Application Task
 * Reads the proximity data from 3 sensors in a multiplex mode and displays it on the USB UART 
 * approximately once per second. The higher the proximity value, the closer the detected object is.
 * @author Stefan Filipovic

#include "board.h"
#include "log.h"
#include "proximity18.h"

static proximity18_t proximity18;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    proximity18_cfg_t proximity18_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.
    proximity18_cfg_setup( &proximity18_cfg );
    PROXIMITY18_MAP_MIKROBUS( proximity18_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == proximity18_init( &proximity18, &proximity18_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( PROXIMITY18_ERROR == proximity18_default_cfg ( &proximity18 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    uint16_t ps1_data, ps2_data, ps3_data;
    if ( PROXIMITY18_ERROR == proximity18_start_measurement ( &proximity18 ) )
        log_error ( &logger, " Start measurement." );
        Delay_ms ( 5000 );
    if ( PROXIMITY18_ERROR == proximity18_wait_for_data_ready ( &proximity18 ) )
        log_error ( &logger, " Wait for data ready." );
        Delay_ms ( 5000 );
    if ( PROXIMITY18_ERROR == proximity18_read_proximity ( &proximity18, &ps1_data, &ps2_data, &ps3_data ) )
        log_error ( &logger, " Read proximity." );
        Delay_ms ( 5000 );
        log_printf ( &logger, " PS1 data: %u\r\n", ps1_data );
        log_printf ( &logger, " PS2 data: %u\r\n", ps2_data );
        log_printf ( &logger, " PS3 data: %u\r\n\n", ps3_data );
    Delay_ms ( 1000 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support