"Pins" are like gateways between the Arduino code running on the chip and the components attached to Arduino. It can refer either to the physical connectors on the board, or it can refer to the pins defined in the code.

"Pins" are like gateways between the Arduino code running on the chip and the components attached to Arduino. It can refer either to the physical connectors on the board, or it can refer to the pins defined in the code.

There are three main types of pins:

  • A digital pin is one that can detect and output a digital signal (i.e. either HIGH or LOW)
  • An analog pin works mostly like a digital pin, except that each one of them also includes an ADC (analogue to digital converter) which can give the Arduino values of 0 to 1024 that is proportional to the input voltage (i.e. 2.5V on a 5V board is 512).
  • A PWM pin (pulse width modulation) is a digital pin that can create a signals that goes on and off very fast. This can be used to create a dimming effect. For more questions related to PWM, see .

A pin can also refer to the physical pin header that you connect wires to. Connect the wire to the GND pin.

Arduino Uno

From http://arduino.cc/en/Main/ArduinoBoardUno

In the photo above, there are 14 digital pins (six of those are PWM), 6 analog pins, and 12 other pins (GND, 5V, 3.3V, etc.).

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