General Arduino I/O pin explanation
Air Manager and Air Player support the Arduino Uno, Nano, Leonardo, Micro and Mega 2560. To see what each pin can do, you can take a look at the Hardware_id_list.
5V Arduino's use a 5 volt input/output voltage. They have one or more 5 volt pins which can be used to power certain parts, like motors or displays. But do note that the output current of these pins is limited.
3.3V Most Arduino's have a 3.3 volt pin. In general this pin is not used, but can be used in case you have any devices requiring 3.3 volt.
Vin This pin is directly connected to the voltage regulator, and sometimes (for example in case of the Mega 2560) the barrel jack. The voltage regulator accepts a voltage from (recommended) 7-12 volt. It is not always necessary to use a remote power supply, in most cases USB power will be sufficient.
GND Ground pin. When you connect a power consuming device, you connect it between either 3.3 volt and ground or 5 volt and ground.
Functionality varies between pins. Note that D0 and D1 cannot be used in any case, as these serve communication. Only the analog pins have an ADC (Analog Digital Converter), but none of the analog pins can generate a PWM signal or drive LED's. To know what each pin can do, take a loot at the Hardware_id_list.
A hardware ID refers to a certain pin on the Arduino, an example would be ARDUINO_LEONARDO_A_D4.
It can be split up in three sections:
- Device type, in this case: ARDUINO_LEONARDO
- Channel: When connecting multiple Leonardo's in this case, they will have to be on different channels. So when connecting another Leonardo, this would be ARDUINO_LEONARDO_B_yourpin. Setting the channel is done with the Arduino Installer: Arduino#Installer.
- Pin number: In the example pin D4 was used.