Measure temperature and humidity easily with SHT41A and STM32F405RG
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Published Mar 11, 2023
Click board™
Temp&Hum 22 Click
Dev Board
Fusion for ARM v8
Compiler
NECTO Studio
MCU
STM32F405RG
Reliable temperature and humidity data, even in the most challenging conditions
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Hardware Overview
How does it work?
Temp&Hum 22 Click is based on the SHT41A, high-accuracy automotive-grade 16-bit relative humidity and temperature sensor from Sensirion. The SHT41A builds on a wholly new and optimized CMOS chip, offering reduced power consumption, accuracy, and a digital I2C interface for the fastest data transfer. It covers extended operating humidity, and temperature ranges from 0 to 100%RH and from -40°C to 125°C with accuracies of ±1%RH and ±0.3°C. The SHT41A's integrated heater allows advanced on-board-diagnostics alongside reliable operation in harsh conditions such as condensing environments.
The sensor performs best when operated within the recommended average temperature and humidity range of 5-60°C and 20-80%RH. Long-term exposure to conditions outside recommended normal range, especially at high relative humidity, may temporarily offset the RH signal. After returning to the recommended average temperature and humidity range, the sensor will recover to within specifications. Also, to maximize the over-temperature when using the heater, reduced heat conduction and heat capacity of the mounted sensor is desired. For this reason, the sensor is placed on this Click board™ in a particular
position, a piece of a standard PCB with a cutout around the sensor area, increasing the decontamination yield and avoiding excess energy consumption. A PCB layout like this is optimized for minimal thermal heat sink influence. This Click board™ can only be operated 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
Fusion for ARM 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 ARM® Cortex®-M based 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, Fusion for ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the Fusion for ARM 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. Fusion for ARM 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.
Microcontroller Overview
MCU Card / MCU
Type
8th Generation
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
196608
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Fusion for ARM v8 as your development board.
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.
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.
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".
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.
Software Support
Library Description
This library contains API for Temp&Hum 22 Click driver.
Key functions:
temphum22_soft_resetThis function performs the software reset by sending the soft reset command.temphum22_read_serial_numThis function reads the 4-bytes unique serial number by using I2C serial interface.temphum22_read_measurement_high_precisionThis function reads the temperature and humidity measurements with high precision.
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 TempHum 22 Click example
*
* # Description
* This example demonstrates the use of Temp & Hum 22 click board by reading
* the temperature and humidity data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver, performs the sensor software reset and then reads
* and displays the sensor unique serial number.
*
* ## Application Task
* Reads the temperature (degC) and the relative humidity (%RH) data and
* displays the results on the USB UART approximately once per second.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "temphum22.h"
static temphum22_t temphum22;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
temphum22_cfg_t temphum22_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.
temphum22_cfg_setup( &temphum22_cfg );
TEMPHUM22_MAP_MIKROBUS( temphum22_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == temphum22_init( &temphum22, &temphum22_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( TEMPHUM22_OK == temphum22_soft_reset ( &temphum22 ) )
{
log_printf ( &logger, " Software reset\r\n" );
}
Delay_1sec ( );
uint32_t serial_num;
if ( TEMPHUM22_OK == temphum22_read_serial_num ( &temphum22, &serial_num ) )
{
log_printf ( &logger, " Serial number: 0x%.8LX\r\n", serial_num );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float temperature, humidity;
if ( TEMPHUM22_OK == temphum22_read_measurement_high_precision ( &temphum22, &temperature, &humidity ) )
{
log_printf ( &logger, " Temperature: %.2f degC\r\n", temperature );
log_printf ( &logger, " Humidity: %.2f %%RH\r\n\n", humidity );
Delay_ms ( 1000 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
