A node is a visual representation of some physical device (such as the ports on an Arduino) or some function (adding, subtracting and more complicated stuff).
led is a simple LED controlling node. It can control only a one-colored
LED. The node has input pins
LUM along with a few other pins you
can ignore for now.
The small colored circles on nodes are called pins. Pins are divided into inputs and outputs. Inputs are always on the top side of nodes, outputs — on the bottom.
Pins are used to transfer data between nodes. Nodes process these values and
take some action or give a result. In this example, the
led node transfers the
led brightnes value (set in
LUM) to the Arduino port (set in
You can change values of pins with a sidebar called Inspector. You will see the Inspector on the left under the list of projects.
lednode. It will make the node selected.