Temp&Hum 2 Click
PID: MIKROE‐3085
Weight: 24 g
Temp‐Hum 2 click is a smart temperature and humidity sensor click board™, packed with
features, that allow easy and simple integration into any design that requires accurate and
reliable humidity and temperature measurements. It measures a wide range of
temperature and relative humidity values with a great accuracy. The Si7034 sensor IC from
Silicon labs used on this Click board™ utilizes the patented industry‐standard low‐K
polymeric dielectrics for humidity sensing. It allows low drift and, power consumption, low
hysteresis, and excellent long‐term stability.
The Si7034 IC also includes a thermal sensor, and all the sensor and thermal calibration
data is stored on‐chip, allowing interchangeability between the different samples of the IC
with no additional calibration steps. These features make Temp‐Hum 2 click a perfect
solution for a wide range of applications that depend on accurate temperature and
humidity readings. It is a perfect choice for various consumer and industry related
applications, such as the indoor weather stations, thermostats and humidistats,
microenvironment centers, respiratory therapy applications, and similar.
The sensor IC used on the Temp Hum 2 click is the Si7034, a digital humidity and
temperature sensor IC with I2C interface, from Silicon Labs. It is a digital relative humidity
and a temperature sensor that integrates temperature and humidity sensor elements, an
analog‐to‐digital converter, signal processing, calibration, and data correction on the chip.
Each chip is factory calibrated, and the calibration data is stored in its non‐volatile memory.
The maximum accuracy achieved with this sensor is ± 4% RH for the humidity range from 0 to
80%.Besides the humidity sensing element, this sensor includes an accurate thermal sensor,
which can achieve up to ±0.4 °C. It is used in conjunction with the humidity measurement,
to allow thermal compensation of the relative humidity measurements.
This sensor IC also has an integrated heating element that is used to evaporate
condensation reducing the effect of the offset accumulation when used in high humidity
conditions, or to implement dew‐point measurement when the Si7034 is used with a
separate temperature sensor. The heating element current can be adjusted by the
appropriate bits in the Humidity Control Register.
Due to the nature of the used sensors, a special care should be taken to reduce the sensor
contamination to a minimum. Particles, dirt or other artifacts collected on the surface of the
exposed polymer film will affect its ability to measure the humidity, and therefore, the
manufacturer recommends protecting the sensor against particles. The sensor otherwise
has a long aging period with minimal drift. Synthetic long‐term stability tests show less
than 0.25 %RH per year drift.
The data provided by the IC is ready to be used directly. Two measurements are done when
a command is received via the I2C. One is the humidity measurement, while the second is
temperature measurement, used for the compensation. By applying this simple formula,
the relative humidity can be directly represented in percentages:
Where RH_DATA is the 16bit value provided by the Si7034 sensor on the Click board™. The
temperature (given in degrees Celsius) reading can be calculated by applying this formula:
Where TEMP_DATA is the 16bit value provided by the Si7034 sensor on the Click board™.
Si7034 IC operates on 1.8V and therefore, a small LDO has to be used to convert 3.3V from
the mikroBUS™ power rail, down to 1.8V. In addition, the I2C signal voltage levels also have
to be converted so it can be used with the MCUs operated with 3.3V. For this purpose, the
Click board™ utilizes the PCA9306, a level shifting IC, made by Texas Instruments. It uses
1.8V as the first reference voltage and 3,3V from the mikroBUS™ power rail as the second
reference voltage, shifting the I2C communication signal levels, allowing this Click board™
to be used with MCUs operated at 3.3V.
The sensor IC is physically located away from other components on the Click board™, so
the heating influence of the surrounding components or PCB is reduced to a minimum,
allowing the accuracy of the Click board™ to stay within the specifications. The i2C lines of
the IC are routed to the mikroBUS™ and supplied by the pull‐up resistors, allowing this
Click board™ to be used right out of the box. Temp‐Hum 2 click uses only 3.3V rail from the
mikroBUS™.
Specifications
Type
Temperature / Humidity
It is a perfect choice for various consumer and industry related
Applications
applications, such as the indoor weather stations, thermostats and
humidistats, microenvironment centers, respiratory therapy applications,
and similar applications.
Si7034, a digital humidity and temperature sensor IC with I2C interface,
On-board modules
from Silicon Labs; PCA9306, a dual bidirectional I2C voltage level translator
from Texas Instruments; AP7331, an LDO regulator from Diodes
Incorporated.
Accurate low-K polymeric dielectric sensor used for capacitive
Key Features
measurement of the humidity, on-chip factory programmed calibration
parameters, operates in the range of 0% to 100% RH, low drift over time.
Interface
I2C
Input Voltage
3.3V
Click board size
M (42.9 x 25.4 mm)
Onboard jumpers and settings
Label
Name
Default
Description
PWR
PWR
-
Power LED indicator
Pinout diagram
This table shows how the pinout on Temp&Hum 2 click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
NC
1
AN
PWM
16
NC
NC
2
RST
INT
15
NC
NC
3
CS
RX
14
NC
Notes
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
SCL
I2C Clock
NC
6
MOSI
SDA
11
SDA
I2C Data
Power supply
3.3V
7
3.3V
5V
10
NC
Ground
GND
8
GND
GND
9
GND
Ground
Software support
We provide a demo application for Temp&Hum 2 click on our Libstock page, as well as a
demo application (example), developed using MikroElektronika compilers. The demo can
run on all the main MikroElektronika development boards.
Library Description
The library initializes and defines the I2C bus driver and drivers that offer a choice for
writing data in the register. The library includes the function for reads query device,
electronic ID, firmware revision, temperature and humidity data. The user can select the
measurement mode and set the Heater.
Key functions :
void temphum2_setMode(uint8_t selectMode, uint8_t speedMode) ‐ Functions for set
measurement mode
void temphum2_getMeasurement( float *dataBuffer ) ‐ Functions for measurement
void temphum2_writeByte(uint8_t reg, uint8_t _data) ‐ Functions for write one byte
in register
Example description
The application is composed of three sections:
System Initialization - Initializes I2C module.
Application Initialization - Initializes driver init, set work mode and Heater.
Application Task - (code snippet) - Reads temperature and humidity and logs values on usbuart
for every 500ms.
void applicationTask()
{
temphum2_getMeasurement( &dataBuffer[0] );
mikrobus_logWrite( " ‐‐‐ Temperature : ", _LOG_TEXT);
FloatToStr( dataBuffer[0] , dataText);
mikrobus_logWrite(dataText, _LOG_TEXT);
mikrobus_logWrite( " C", _LOG_LINE);
mikrobus_logWrite( " ‐‐‐ Humidity : ", _LOG_TEXT);
FloatToStr( dataBuffer[1] , dataText);
mikrobus_logWrite(dataText, _LOG_TEXT);
mikrobus_logWrite( " %RH", _LOG_LINE);
Delay_ms( 500 );
}
The full application pre, and ready to use projects can be found on our LibStock page.
mikroE Libraries used in the example:
Conversions
I2C
UART
Additional notes and information
Depending on the development board you are using, you may need USB UART click, USB
UART 2 click or RS232 click to connect to your PC, for development systems with no UART
to USB interface available on the board. The terminal available in all
MikroElektronika compilers, or any other terminal application of your choice, can be used
to read the message.
mikroSDK
This click board is supported with mikroSDK ‐ MikroElektronika Software Development
Kit. To ensure proper operation of mikroSDK compliant click board demo applications,
mikroSDK should be downloaded from the LibStock and installed for the compiler you are
using.
For more information about mikroSDK, visit the official page.
Downloads
mikroBUS™ Standard specification
LibStock: mikroSDK
Temp&Hum 2 click schematic
Temp&Hum 2 click: 2d and 3d files
Si7034 datasheet
LibStock: Temp&Hum2 click library
https://www.mikroe.com/temphum-2-click?search_query=MIKROE-3085&results=1 7-11-18