The Arduino Uno

The Aruino Uno has 32 accessible pins that can be used for connecting various components. The pinout diagram below provides a useful reference.

There are:

• power pins at 0V (or ground, GND), 5V and 3.3V
• 14 dedicated digital input/output (I/O) pins
• 6 analog I/O pins that can also be used a digital pins
• 2 digital pins that can be used to communicate directly with your computer via serial
• Digital pins that can be used to communicate with specialist sensors using I2C or SPI protocols

Some functions are available on more than one set of pins. For example pin 11 is available on the male header at the bottom of the diagram with a gnd and a 5V pin next to it. This is for the direct connection of a servo to the Arduino.