Attain precise measurement of temperature and relative humidity with the SHT33-DIS-B2.5KS and PIC32MZ2048EFM100
High-reliability relative humidity and temperature sensing solution
Published Jul 08, 2024
Click board™
Temp&Hum 25 Click
Dev. board
Curiosity PIC32 MZ EF
Compiler
NECTO Studio
MCU
PIC32MZ2048EFM100
Useful for environmental monitoring stations, weather data collection, or agriculture applications where temperature and humidity are crucial factors
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Hardware Overview
How does it work?
Temp&Hum 25 Click is based on the SHT33-DIS-B2.5KS, a high-reliability, third-generation relative humidity and temperature sensor from Sensirion. This advanced sensor is part of Sensirion's new family of low drift digital calibrated and ISO17025-certified sensors, offering exceptional accuracy and reliability. The SHT33-DIS-B2.5KS integrates ISO17025-certified temperature sensing with highly precise humidity measurements, all within a single small package. Using the industry-proven CMOSens® technology, this sensor provides enhanced computational power, increased reliability, and superior accuracy compared to its predecessors. Its robust performance and reliability make it a versatile choice for a wide range of temperature and humidity-related applications in portable electronics and industrial, consumer, and environmental scenarios. Each SHT33 sensor is uniquely identifiable by its serial number and comes with an ISO17025-certified calibration certificate for temperature measurements. The SHT33-DIS-B2.5KS operates within a range of 0-100% RH and -40 to +125°C, with optimal performance achieved within the recommended temperature and humidity range of 5°C-60°C and
20%RH-80%RH, respectively. While long-term exposure to conditions outside these normal ranges, particularly high humidity, may temporarily offset the relative humidity signal, the sensor will re-calibrate itself upon returning to normal conditions. However, prolonged exposure to extreme environments can accelerate sensor aging. Additional notable features include its full functionality in condensing environments and true NIST-traceability, ensuring reliable and accurate measurements in various conditions. This Click board™ is designed in a unique format supporting the newly introduced MIKROE feature called "Click Snap." Unlike the standardized version of Click boards, this feature allows the main sensor area to become movable by breaking the PCB, opening up many new possibilities for implementation. Thanks to the Snap feature, the SHT33-DIS-B2.5KS can operate autonomously by accessing its signals directly on the pins marked 1-8. Additionally, the Snap part includes a specified and fixed screw hole position, enabling users to secure the Snap board in their desired location. Temp&Hum 25 Click uses a standard 2-Wire I2C interface to communicate with the host MCU with fast-mode support and
frequencies up to 1MHz. In addition to I2C pins, the device allows the selection of I2C addresses between 0x44 and 0x45 via an SMD jumper marked as ADDR SEL (0 set by default). The SHT33-DIS-B2.5KS can be reset via the RST pin of the mikroBUS™ socket, through a general call, or software as a soft reset. Resetting over the RST pin or through a general call (according to I2C specifications) achieves a full reset, while with the soft reset, the sensor resets the system controller and reloads calibration data from memory. In addition, this Click board™ comes with 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. 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 as a reference for further development.
Features overview
Development board
Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand
functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,
which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
2048
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
524288
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 Curiosity PIC32 MZ EF 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 25 Click driver.
Key functions:
temphum25_read_serial_num- This function reads the 4-bytes unique serial number by using I2C serial interfacetemphum25_start_measurement- This function starts the measurement by sending the selected measurement commandtemphum25_read_measurement- This function reads the temperature and humidity measurements results
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 25 Click example
*
* # Description
* This example demonstrates the use of TempHum 25 click board by reading
* the temperature and humidity data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver, performs the device reset, reads and displays
* the sensor unique serial number, and then starts the measurements with 1 MPS.
*
* ## 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 "temphum25.h"
static temphum25_t temphum25;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
temphum25_cfg_t temphum25_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.
temphum25_cfg_setup( &temphum25_cfg );
TEMPHUM25_MAP_MIKROBUS( temphum25_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == temphum25_init( &temphum25, &temphum25_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
temphum25_reset_device ( &temphum25 );
uint32_t serial_num = 0;
if ( TEMPHUM25_OK == temphum25_read_serial_num ( &temphum25, &serial_num ) )
{
log_printf ( &logger, " Serial number: 0x%.8LX\r\n", serial_num );
}
temphum25_start_measurement ( &temphum25, TEMPHUM25_CMD_MEAS_CONT_REP_HIGH_MPS_1 );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float temperature = 0;
float humidity = 0;
if ( TEMPHUM25_OK == temphum25_read_measurement ( &temphum25, &temperature, &humidity ) )
{
log_printf ( &logger, " Temperature: %.2f degC\r\n", temperature );
log_printf ( &logger, " Humidity: %.2f %%RH\r\n\n", humidity );
Delay_ms ( 1000 );
}
}
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
