10 min

Provide info of object presence or absence using GP2S700HCP and STM32F723ZE

Detect – Inform – React !

IR REFLECT Click with UNI-DS v8

Published Jun 22, 2023

Click board™


Development board



NECTO Studio



Uncover object presence and precise positioning through the analysis of reflected light



Hardware Overview

How does it work?

IR REFLECT is based on the GP2S700HCP, a phototransistor output reflective photo interrupter from Sharp Microelectronics. It consists of one infrared emitter and one receiver facing the same direction towards the object. When the infrared beam from the emitter bounces back to the emitter when an object is placed within range, it triggers the photo interrupter, thus activating the sensor. The board can set off a false alarm if the sensor is exposed to other infrared light sources, such as an ordinary incandescent light bulb.

Infrared light will not reflect from the black surface, so the Click board™ will not detect it either. Meanwhile, reflective metallic surfaces will trigger the sensor from a more extensive range. The IR Reflect Click board communicates with the host MCU by sending analog values over the AN pin of the mikroBUS™ socket. In addition, this Click board™ features an LM2903, a low-power dual voltage comparator from STMicroelectronics. With the help of a P1 potentiometer and this voltage comparator, it is possible to set an

interrupt threshold that can provide information over an INT pin of this Click board™. The interrupt will also trigger an INT LED as a visual indicator. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

IR REFLECT Click hardware overview 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-M7

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Analog Signal
Power Supply
Object Detection Interrupt
Power Supply

Take a closer look


IR REFLECT 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 IR REFLECT Click driver.

Key functions:

  • irreflect_reflect_status - Function detecting interrupt states of IR reflection

  • irreflect_analog_status - Function detecting states of analog pin of IR reflection

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 IR reflect Click example
 * # Description
 * Example demonstrates the use of IR Reflect Click board.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initialization driver enables - Start write log.
 * ## Application Task  
 * This is a example which demonstrates the use of IR Reflect Click board.
 * On this type of photointerrupter the infrared emitter and receiver are facing the same direction,
 * the infrared beam from the emitter gets bounced back to the receiver when an object 
 * is placed within the detecting range of the sensor ( optimal range is 3mm ).
 * These sensors are used to detect an object's presence or motion, such as a piece of paper passing through a printer
 * and counting when sensor is triggered.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * Data logs on usb uart when the sensor is triggered.
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "irreflect.h"

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

static irreflect_t irreflect;
static log_t logger;

static uint8_t ir_state;
static uint8_t ir_state_old;
static uint16_t counter;

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

void application_init ( void )
    log_cfg_t log_cfg;
    irreflect_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 ----\n");

    //  Click initialization.
    irreflect_cfg_setup( &cfg );
    irreflect_init( &irreflect, &cfg );
    ir_state = 0;
    ir_state_old = 0;
    counter = 1;

void application_task ( void )
    //  Task implementation.
    ir_state = irreflect_reflect_status( &irreflect );

    if ( ir_state_old != ir_state )
        if ( ir_state )
            log_printf( &logger, "  Counter = %u\n", counter);
        ir_state_old = ir_state;

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support