The DHT22 2 Click Board™ is used for measuring the environmental temperature and relative humidity. It uses the AM2322 sensor from Aosong, with very accurate thermal and humidity measuring capabilities. It can use either 1-Wire or I2C protocol to communicate with the integrated circuit.
Attributes like the ultra-small size, low power consumption, signal transmission distance up to 20 meters, make this sensor the perfect choice for all kinds of applications that require measurement of the temperature and humidity.
The DHT22 2 Click Board™ is used for measuring the environmental temperature and relative humidity. It uses the AM2322 sensor, with very accurate thermal and humidity measuring capabilities. It can use either 1-Wire or I2C protocol to communicate with the integrated circuit.
Attributes like the ultra-small size, low-power consumption, signal transmission distance up to 20 meters, make this sensor the perfect choice for all kinds of applications that require measurement of the temperature and humidity.
How Does The DHT22 2 Click Board™ Work?
The DHT22 2 Click Board™ is based on the AM2322 sensor. This sensor contains humidity and temperature measurement elements, compensated and calibrated in the accurate calibration chamber. The calibration coefficient is saved in the OTP memory of an integrated MCU. The integrated MCU also provides I2C or 1-Wire interface, selectable by the onboard SMD jumper selectors. The operating voltage can also be selected by the onboard SMD jumper.
Typical temperature accuracy is ±0.3°C, while relative humidity accuracy is 2% RH, with the resolution of 0.1 for both measured properties.
I2C/1-Wire interface is used to communicate with the host MCU, sending the measurement data every 2 seconds. Proprietary data collecting techniques are used to average the sampled values, after which the result is sent via the I2C/1-Wire bus.
Specifications
Type
Temperature & humidity
Applications
Weather stations, HVAC systems, humidity regulators and so on
On-board modules
AM2322 sensor with very accurate thermal and humidity measuring capabilities
Key Features
Great measuring accuracy: ±0.3°C, ±2%RH at 25°C, ultra-small size, low power consumption, signal transmission distance up to 20 meters.
Interface
1-Wire,I2C
Compatibility
mikroBUS
Click board size
M (42.9 x 25.4 mm)
Input Voltage
3.3V or 5V
Pinout diagram
This table shows how the pinout on the DHT22 2 Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
NC
1
AN
PWM
16
OW
1-wire
NC
2
RST
INT
15
NC
NC
3
CS
RX
14
NC
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
+5V
Power supply
Ground
GND
8
GND
GND
9
GND
Ground
DHT22 2 click maximum ratings
Description
Min
Typ
Max
Unit
Logic voltage level
3.3
5
5.5
V
SCL clock frequency
100
kHz
Measuring range (T)
-40
+80
°C
Measuring range (RH)
0%
99%
RH
Onboard settings and indicators
Label
Name
Default
Description
JP1
OW/SCL
Right
Digital interface selection. Left position 1-Wire, right position I2C.
JP2
OW/SDA
Right
Digital interface selection. Left position 1-Wire, right position I2C.
JP3
LOGIC SEL
Left
Logic level voltage selection. Left position 3.3V, right position 5V.
We provide a library for the DHT22 2 Click Board™ 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
Library contains key functions used to read temperature and humidity data from the DHT22 2 click.
float DHT22_2_getTemperature(); - Function for reading temperature from sensor
float DHT22_2_getHumidity() - Function for reading humidity from sensor
Example Description
The example uses the library functions to read the temperature and humidity from the sensor and sends the data to the user, via the UART interface. The two functions use I2C interface to communicate with the MCU. Both of these functions return data in floating format, which only needs to be converted to a string with the compiler function FloatToString, before it is sent to the UART module. After that, the temperature and the humidity data can be viewed using the UART terminal.
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
UART
I2C
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.
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