30 min

Achieve comprehensive and real-time data on air movement with LHDULTRAM012UB3 and STM32L041C6

Venture into the future of air flow monitoring

Air Flow Click with UNI Clicker

Published Oct 14, 2023

Click board™

Air Flow Click

Development board

UNI Clicker


NECTO Studio



Our air flow monitoring solution is designed to provide accurate and real-time insights into air circulation, catering to a wide spectrum of industries from HVAC to cleanrooms



Hardware Overview

How does it work?

Air Flow Click is based on ses the LHDULTRAM012UB3, an LHD ULTRA series flow-based 2-in-1 differential pressure sensor from TE Connectivity Measurement Specialties. It comprises two combined calorimetric micro-flow channels and two sensor elements on a single chip. The first sensing element ensures precise measurement of low differential pressures with high resolution, and the second sensing element is optimized for pressures in the upper measuring range. A fast-response 24-bit onboard controller delivers precise measurements across the dynamic range from 0 to 1250Pa. The specific concept of the LHDULTRAM012UB3 ensures

continuous, highly reliable, economically efficient operation, outstanding long-term stability, and precision with patented real-time offset compensation and linearization techniques. The LHD ULTRA's high flow impedance ensures product-specific insensitivity to dust/moisture and minimal flow leakage. Air Flow Click allows for both I2C and SPI interfaces with a maximum frequency of 100kHz for I2C and 1MHz for SPI communication. The selection can be made by positioning SMD jumpers labeled COMM SEL to an appropriate position. Note that all the jumpers' positions must be on the same side, or the Click board™ may become unresponsive. While the I2C

interface is selected, the LHDULTRAM012UB3 allows the choice of the least significant bit (LSB) of its I2C slave address using the SMD jumpers labeled as A0 and A1 to an appropriate position marked as 0 and 1. Also, an additional ready signal, routed on the INT pin of the mikroBUS™ socket, is added, indicating that new data is ready for the host. 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.

Air Flow Click top side image
Air Flow Click bottom side image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI 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.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M0

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Clock
Power Supply
Data Ready
I2C Clock
I2C Data

Take a closer look


Air Flow Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker Access 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Air Flow Click driver.

Key functions:

  • airflow_reset_device - Reset device

  • airflow_get_differential_pressure - Reads differential pressure

  • airflow_get_atmospheric_pressure - Reads atmospheric pressure and temperature

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 AirFlow Click example
 * # Description
 * This example showcases ability for device to read differential 
 * pressure, atmospheric pressure and ambient temperature.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initialize host communication modules (UART, I2C/SPI). Read 
 * electric signature data from device and logs it to terminal.
 * ## Application Task
 * Reads differential pressure in Pa, atmospheric pressure in mBar 
 * and ambient temperature in C every 500ms and logs read data.
 * @author Luka Filipovic

#include "board.h"
#include "log.h"
#include "airflow.h"

static airflow_t airflow;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    airflow_cfg_t airflow_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 );
    Delay_ms( 100 );
    log_info( &logger, " Application Init " );

    // Click initialization.
    airflow_cfg_setup( &airflow_cfg );
    AIRFLOW_MAP_MIKROBUS( airflow_cfg, MIKROBUS_1 );
    err_t init_flag  = airflow_init( &airflow, &airflow_cfg );
    if ( ( init_flag == I2C_MASTER_ERROR ) || ( init_flag == SPI_MASTER_ERROR ) ) 
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    airflow_reset_device( &airflow );
    if ( airflow_default_cfg ( &airflow ) < 0 )
        log_error( &logger, " Read" );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
        log_printf( &logger, "Firmware version: %d.%d\r\n", ( int16_t )airflow.major_fw_ver, ( int16_t )airflow.minor_fw_ver );
        //part number
        log_printf( &logger, "Part number: " );
        for ( uint8_t pn = 0; pn < 11; pn++ )
            log_printf( &logger, "%c", airflow.part_number[ pn ] );
        log_printf( &logger, "\r\n" );
        //lot number
        log_printf( &logger, "Lot number: " );
        for ( uint8_t pn = 0; pn < 7; pn++ )
            log_printf( &logger, "%c", airflow.lot_number[ pn ] );
        log_printf( &logger, "\r\n" );
        //pressure range
        log_printf( &logger, "Pressure range: %d\r\n", airflow.pressure_range );
        //output type
        log_printf( &logger, "Output type: %c\r\n", airflow.output_type );
        //scale factor
        log_printf( &logger, "Scale factor: %d\r\n", airflow.scale_factor );
        //calibration id
        log_printf( &logger, "Calibration ID: %s\r\n", airflow.calibration_id );
        log_printf( &logger, "Week: %d\r\n", ( int16_t )airflow.week );
        log_printf( &logger, "Year: %d\r\n", ( int16_t )airflow.year );
        //sequence number
        log_printf( &logger, "Sequence number: %d\r\n", airflow.sequence_number );
    Delay_ms( 2000 );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    float pressure_data, temperature_data;
    airflow_get_differential_pressure( &airflow, &pressure_data );
    log_printf( &logger, "Differential pressure[Pa]: %.2f\r\n", pressure_data );
    airflow_get_atmospheric_pressure( &airflow, &pressure_data, &temperature_data );
    log_printf( &logger, "Atmospheric pressure[mBar]: %.2f\r\nTemperature[degC]: %.2f\r\n", pressure_data, temperature_data );
    log_printf( &logger, "***********************************************************\r\n" );
    Delay_ms( 500 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support