DHT22 Add-On Library for Arduino

Arduino Add-on library for the DHT22 Temperature and Humidity Sensor

This add-on allows MATLAB to interface with DHT22 temperature and humidity sensor connected to Arduino hardware. With the add-on, you can read the measured temperature from the device in degrees Celsius and humidity as a percentage.

This add-on is supported for MATLAB R2019a or higher.

Sample usage:

Create arduino object with the add-on library

a = arduino('COM8', 'Uno', 'Libraries', 'Adafruit/DHT22');

Create DHT22 sensor object

sensor = addon(a, 'Adafruit/DHT22', 'D6');

Read temperature measurement

temperature = readTemperature(sensor);

Important: Before using this add-on library in MATLAB, you need to install the Adafruit Sensor library and Adafruit DHT library. Here are the instructions:

Installation:

To install the Adafruit Sensor library:

1. Download the zip file from https://github.com/adafruit/Adafruit_Sensor
2. Unpackage the zip into local directory and rename the folder to ‘Adafruit_Sensor'.
3. Move the ‘Adafruit_Sensor’ folder into the "libraries" folder inside your Arduino sketchbook folder.

To install the Adafruit DHT library:

1. Download the zip file from https://github.com/adafruit/DHT-sensor-library
2. Unpackage the zip into local directory and rename the folder to ‘DHT’.
3. Move the ‘DHT’ folder into the "libraries" folder inside your Arduino sketchbook folder.

For R2019a the sketchbook folder path is:

• On Windows®, the default path is "Documents\Arduino\libraries\"
• On Mac®, the default path is "~/Documents/Arduino/libraries/"
• On Linux®, the default path is "/home/<username>/Arduino/libraries"

For R2019b and later the sketchbook folder path is:

• On Windows®, the default path is "Arduino IDE Path\portable\sketchbook\libraries\"
• On Mac®, the default path is "~/Documents/Arduino/libraries/"
• On Linux®, the default path is "Arduino IDE Path/portable/sketchbook/libraries/"

Note: Arduino IDE Path is returned by the following command in the MATLAB Command Window

arduinoio.IDERoot

For R2024a and later, across all operating systems, the library location can be determined by executing the following command:

fullfile(arduinoio.CLIRoot, 'user','libraries')

Troubleshooting tips:

1. After installing this add-on library and the required Arduino library, type "listArduinoLibraries" in MATLAB to see if the add-on is properly installed.
2. Wire up the Arduino board and the add-on device properly before creating the object to avoid a connection error in MATLAB.
3. Refer to the documentation for details on usage and syntax. It can be found under Supplemental Software in the product documentation.

Feel free to contact the MATLAB Hardware Team if you have questions about this add-on library:

http://www.mathworks.com/matlabcentral/profile/contact/4922363-mathworks-matlab-hardware-team