Measure temperature and humidity easily with SHT41A and ATmega328P
Feel comfortable at all times
Published Feb 14, 2024
Click board™
Temp&Hum 22 Click
Dev. board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328P
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
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
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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 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
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 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
