30 min

Make your personal weather monitor with HIH8130-021-001 and dsPIC33EP512MU810

Accurate weather monitoring

Temp&Hum 21 Click with Clicker 2 for dsPIC33

Published Apr 04, 2023

Click board™

Temp&Hum 21 Click

Development board

Clicker 2 for dsPIC33


NECTO Studio



In case the online weather forecast is not that accurate



Hardware Overview

How does it work?

Temp&Hum 21 Click is based on the HIH8130-021-001, a highly accurate, fully-calibrated digital humidity and temperature sensor from Honeywell Sensing and Productivity Solutions. The humidity can be measured within a range of 0 to 100%RH, while the temperature sensor is designed for a range of -40 to +120°C. The typical accuracy for humidity is ±2%RH in the measuring range of 10 up to 90%RH at ambient temperature and ±0.5°C for its operating temperature range with low power consumption. The HIH8130-021-001 communicates with MCU using the standard I2C 2-Wire interface to read and write data supporting

Fast Mode operation with a clock frequency up to 400kHz, providing factory-calibrated 14-bit data to the host controller. High 14-bit humidity and 14-bit temperature sensor resolution within the application help the user’s design detect the slightest relative humidity or temperature change. It also has an alarm feature with configurable alarm thresholds routed to the ALH and ALL pins of the mikroBUS™ socket for preset control at a minimum and maximum humidity and temperature. These alarm thresholds are set to generate alarms when the actual values in the devices cross the defined threshold values.

To activate the external setting of the alarm thresholds, it is necessary to populate resistors R4 and R5, which are not populated by default, to enable an external setting on an unpopulated header in the middle of the Click board™. 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. However, the 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.

Temp&Hum 21 Click top side image
Temp&Hum 21 Click lateral side image
Temp&Hum 21 Click bottom side image

Features overview

Development board

Clicker 2 for dsPIC33 is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 16-bit dsPIC33E family microcontroller, the dsPIC33EP512MU810 from Microchip, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a mikroProg programmer connector, and two 26-pin headers for interfacing with external electronics. Its compact design with clear and easily recognizable silkscreen markings allows you to build gadgets with unique

functionalities and features quickly. Each part of the Clicker 2 for dsPIC33 development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the Clicker 2 for dsPIC33 programming method, using a USB HID mikroBootloader or an external mikroProg connector for dsPIC33 programmer, the Clicker 2 board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Micro-B cable, where onboard voltage regulators provide the appropriate voltage levels to each

component on the board, or using a Li-Polymer battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several user-configurable buttons and LED indicators. Clicker 2 for dsPIC33 is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Clicker 2 for dsPIC33 dimensions image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Alarm Low Threshold
Power Supply
Alarm High Threshold
I2C Clock
I2C Data
Power Supply

Take a closer look


Temp&Hum 21 Click Schematic schematic

Step by step

Project assembly

Clicker 2 for PIC32MZ front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Clicker 2 for dsPIC33 as your development board.

Clicker 2 for PIC32MZ front image hardware assembly
Buck 22 Click front image hardware assembly
Prog-cut hardware assembly
Micro B Connector Clicker 2 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Flip&Click PIC32MZ MCU step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for TempHum 21 Click driver.

Key functions:

  • temphum21_read_measurementThis function requests measurement and waits for a measurement to complete and, after that, reads the temperature in Celsius and relative humidity in percents.

  • temphum21_get_all_pin This function returns the alarm low (ALL) pin logic state.

  • temphum21_get_alh_pin This function returns the alarm high (ALH) pin logic state.

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 TempHum21 Click example
 * # Description
 * This example demonstrates the use of Temp & Hum 21 click board by reading
 * the temperature and humidity data.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and logger.
 * ## Application Task
 * Reads the temperature (Celsius) and humidity (Percents) data and displays the
 * results on the USB UART approximately once per second.
 * @author Stefan Filipovic

#include "board.h"
#include "log.h"
#include "temphum21.h"

static temphum21_t temphum21;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    temphum21_cfg_t temphum21_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.
    temphum21_cfg_setup( &temphum21_cfg );
    TEMPHUM21_MAP_MIKROBUS( temphum21_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == temphum21_init( &temphum21, &temphum21_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    float temperature, humidity;
    if ( TEMPHUM21_STATUS_NORMAL_OP == temphum21_read_measurement ( &temphum21, &temperature, &humidity ) )
        log_printf ( &logger, " Temperature: %.2f C\r\n", temperature );
        log_printf ( &logger, " Humidity: %.2f %%\r\n\n", humidity );
        Delay_ms ( 1000 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

// ------------------------------------------------------------------------ END

Additional Support