In Chapter 1, The Arduino, we saw that the Arduino has several digital pins that we can connect external sensors and other devices to. Before we use these pins, we should configure them for either input or output depending on what we are using them for. To do this, we use the pinMode() function that is built into the Arduino programming language. Usually for smaller sketches we call the pinMode() function within the setup() function; however, this is not required. The following code shows the syntax for the pinMode() function:
pinMode(pin, mode);
This function is called with two parameters. The first is the number of the pin that we are setting and the second is the mode for the pin. The mode for the pin can be either INPUT, to read the value from the pin (external sensor writes a value to the pin), or OUTPUT, to set the value for the pin. The following...