30 min

Achieve comprehensive and real-time data on air movement with LHDULTRAM012UB3 and ATmega324P

Venture into the future of air flow monitoring

Air Flow Click with EasyAVR v7

Published Oct 14, 2023

Click board™

Air Flow Click

Development board

EasyAVR v7


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

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU




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

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

EasyAVR v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyAVR v7 Access DIP 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 DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step 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 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