Receive accurate readings of air pressure with LPS25HB and ATmega328P
Your favorite weather forecaster
Published Feb 14, 2024
Click board™
Barometer Click
Dev. board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328P
With its ability to detect subtle pressure variations, this solution helps you make informed decisions regarding outdoor activities and travel plans
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Hardware Overview
How does it work?
Barometer Click is based on the LPS25HB, a high-resolution, digital output pressure sensor from STMicroelectronics. The LPS25HB includes a sensing element based on a piezoresistive Wheatstone bridge approach. When pressure is applied, the membrane deflection induces an imbalance in the Wheatstone bridge piezoresistance, whose output signal is converted into a 24-bit digital value by the selectable digital interface. The LPS25HB's interface is factory-calibrated at three temperatures and two pressures for sensitivity and accuracy. The LPS25HB delivers low-pressure noise with low power consumption and operates over an extended temperature range. It has a selectable
absolute pressure range, from 260 up to 1260hPa, with typical absolute pressure and temperature accuracy of ±0.2hPa and ±2°C, ideally suited for various pressure-based applications. Barometer Click allows the use of both I2C and SPI interfaces with a maximum frequency of 400kHz for I2C and 10MHz for SPI communication. The selection can be made by positioning SMD jumpers in an appropriate position marked as I2C or SPI. 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 LPS25HB allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled I2C ADR. This Click board™
also possesses an additional interrupt pin, routed to the INT pin on the mikroBUS™ socket labeled as RDY, indicating when a new measured pressure data is available, simplifying data synchronization in digital systems or optimizing system power consumption. 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. 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.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for Barometer Click driver.
Key functions:
barometer_get_temperature_c- Read temperature in degrees Celsius functionbarometer_get_pressure- Read pressure in milibars functionbarometer_check_status- Check sensor status function
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* \file
* \brief Barometer Click example
*
* # Description
* This application measures temperature and pressure data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization driver enable's - I2C, set default configuration and start write log.
*
* ## Application Task
* This is a example which demonstrates the use of Barometer Click board.
* ## NOTE
* External pull-up resistors are required on I2C lines, if the Click board is configured for I2C mode.
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "barometer.h"
// ------------------------------------------------------------------ VARIABLES
static barometer_t barometer;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
barometer_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.
barometer_cfg_setup( &cfg );
BAROMETER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
barometer_init( &barometer, &cfg );
barometer_default_cfg( &barometer );
// Check sensor id
if ( barometer_check_id( &barometer ) != BAROMETER_DEVICE_ID )
{
log_printf( &logger, " ERROR \r\n " );
}
else
{
log_printf( &logger, " Initialization \r\n" );
}
log_printf( &logger, "-------------------------------- \r\n" );
Delay_100ms( );
}
void application_task ( void )
{
float temperature_c;
float pressure;
temperature_c = barometer_get_temperature_c( &barometer );
Delay_100ms( );
pressure = barometer_get_pressure( &barometer );
Delay_100ms( );
log_printf( &logger, " Temperature : %.2f\r\n", temperature_c );
log_printf( &logger, " Pressure : %.2f\r\n", pressure );
log_printf( &logger, "-------------------------------- \r\n" );
Delay_1sec( );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Pressure
