Ensure healthy air quality by monitoring humidity and temperature with HDC3021 and STM32F031K6
Your solution for accurate environmental data
Published Oct 01, 2024
Click board™
Temp&Hum 24 Click
Dev. board
Nucleo 32 with STM32F031K6 MCU
Compiler
NECTO Studio
MCU
STM32F031K6
By seamlessly integrating temperature and humidity measurement, this solution enables real-time insights for efficient climate control and environmental management
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Hardware Overview
How does it work?
Temp&Hum 24 Click is based on the HDC3021, an integrated interface digital sensor that incorporates both humidity and temperature sensing elements, an analog-to-digital converter, calibration memory, and an I2C compatible interface from Texas Instruments in one package. The sensor performs best when operated within the recommended average temperature and humidity range of 0-50°C and 10-50%RH, with each measurement in a 16-bit format. The HDC3021 also provides excellent measurement accuracy at low power (±0.5%RH and ±0.1°C over a wide operating temperature range). The HDC3021 measures relative humidity through variations in the capacitance of a polymer dielectric. This sensor has a polyimide tape to cover the opening of the humidity sensor element, which protects it from pollutants that can be produced as part of the manufacturing process. The tape must be removed after the final stages of assembly to measure the relative humidity in the ambient environment accurately. To remove the polyimide tape from the humidity sensor element, TI recommends using an ESD-safe tweezer to
grip the adhesive-free tab in the top right corner and slowly peel the adhesive from the top-right corner towards the bottom-left corner in an upward direction. This will help to reduce the risk of scratching the humidity sensor element. Due to contaminants, the natural aging of the sensor's polymer dielectric, and exposure to extreme operating conditions resulting in long-term drift, the HDC3021 accuracy can incur an offset. Thanks to the Offset Error Correction, the RH sensor offset reduces due to aging, exposure to extreme operating conditions, and contaminants to return the sensor to within accuracy specifications. This Click board™ communicates with an MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Fast Mode Plus up to 1MHz. The HDC3021 also has two measurement modes: Trigger-on-demand and Auto Measurement. Trigger-on Demand is a single temperature and relative humidity measurement reading triggered through an I2C command as needed. After the measurement is converted, the sensor remains in Sleep mode until another I2C command is
received. Auto Measurement mode is a recurring temperature and relative humidity measurement reading, eliminating the need to initiate a measurement request through an I2C command repeatedly. The HDC3021 wakes from Sleep to measurement mode in this mode based on the selected sampling rate. Besides, the HDC3021 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumpers labeled ADDR SEL. It also possesses an additional interrupt alert signal, routed on the ALR pin of the mikroBUS™ socket, to provide a notification of ambient temperature and relative humidity measurements that violate programmed thresholds and general reset function routed on the RST pin of the mikroBUS™ socket. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used for further development.
Features overview
Development board
Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The
board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,
and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
32
Silicon Vendor
STMicroelectronics
Pin count
32
RAM (Bytes)
4096
You complete me!
Accessories
Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.
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 Nucleo 32 with STM32F031K6 MCU 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 24 Click driver.
Key functions:
temphum24_read_temp_and_rh- This function reads the temperature in celsius and the relative humidity level in percentstemphum24_read_temp_history- This function reads the temperature minimum and maximum values since the beginning of the measurementstemphum24_read_rh_history- This function reads the relative humidity minimum and maximum values since the beginning of measurements
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 24 Click example
*
* # Description
* This example demonstrates the use of Temp & Hum 24 click board by reading
* the temperature and humidity data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration which
* resets the device and starts the auto measurement mode with data rate of 1 Hz.
*
* ## Application Task
* Reads the temperature (degrees C) and the relative humidity (%RH) data and
* displays the results on the USB UART approximately once per second. It also
* reads and displays the minimum and maximum values measured since the beginning
* of measurements.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "temphum24.h"
static temphum24_t temphum24;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
temphum24_cfg_t temphum24_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.
temphum24_cfg_setup( &temphum24_cfg );
TEMPHUM24_MAP_MIKROBUS( temphum24_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == temphum24_init( &temphum24, &temphum24_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( TEMPHUM24_ERROR == temphum24_default_cfg ( &temphum24 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float temp = 0, hum = 0;
if ( TEMPHUM24_OK == temphum24_read_temp_and_rh ( &temphum24, &temp, &hum ) )
{
float min_temp = 0, max_temp = 0;
float min_rh = 0, max_rh = 0;
log_printf ( &logger, " Temperature: %.2f C\r\n", temp );
if ( TEMPHUM24_OK == temphum24_read_temp_history ( &temphum24, &min_temp, &max_temp ) )
{
log_printf ( &logger, " MIN: %.2f C\r\n MAX: %.2f C\r\n", min_temp, max_temp );
}
log_printf ( &logger, "\r\n Humidity: %.1f %%RH\r\n", hum );
if ( TEMPHUM24_OK == temphum24_read_rh_history ( &temphum24, &min_rh, &max_rh ) )
{
log_printf ( &logger, " MIN: %.1f %%RH\r\n MAX: %.1f %%RH\r\n", min_rh, max_rh );
}
log_printf ( &logger, "----------------------\r\n" );
Delay_ms ( 1000 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Temperature & humidity
