Add Libraries¶
A library, gathering some function definitions and header files, usually contains two files: .h (header file, including function statement, Macro definition, constructor definition, etc.) and .cpp (execution file, with function implementation, variable definition, and so on). When you need to use a function in some library, you just need to add a header file (e.g. #include <dht.h>), and then call that function. This can make your code more concise. If you don’t want to use the library, you can also write that function definition directly. Though as a result, the code will be long and inconvenient to read.
Some libraries are already built in the Arduino IDE, when some others may need to be added. So now let’s see how to add one. There are 2 methods for that.
Method 1 Add .ZIP Library¶
Directly import the library in Arduino IDE (take Dht as an example below). The advantage of this method is easy to understand and operate, but on the other hand, only one library can be imported at a time. So it is inconvenient when you need to add quite a lot of libraries.
Step 1: Select Sketch -> Include Library -> Add ZIP Library.

Step 2: Find Library
folder, Click Open.

Step 3: When you see Library added to your libraries. Check “Include library” menu, it means you have added the library successfully. Please use the same method to add other libraries then.

Method 2 Manually Add¶
You can also try to put the library in the libraries
folder of your sketchbook by yourself. This method can
copy all libraries and add them at a time, but first you need to find the path where the libraries
folder is located.
Step 1: You can find or change the location of your libraries
folder at File > Preferences > Sketchbook location.

Step 2: Go to the directory 3in1-kit/learning_project/libraries
and unzip and copy all the folders inside.

Step 3: Go to the location of your libraries
folder(find from Arduino IDE), click to open it.

Step 4: Paste all the unzipped folders of libraries into the libraries
folder.

There is also a way to use the Library Manager, but the libraries added using this method are not necessarily compatible with the code we provide, so it is not recommended.
Here is the link to the official Arduino tutorial: https://docs.arduino.cc/software/ide-v1/tutorials/installing-libraries